diff --git a/.ai/CONVENTIONS.md b/.ai/CONVENTIONS.md
index 9a3f4dd..3cc14fe 100644
--- a/.ai/CONVENTIONS.md
+++ b/.ai/CONVENTIONS.md
@@ -7,6 +7,7 @@
 | Решение / сигнал | Читать |
 | --- | --- |
 | Новый файл/suffix/layer; поиск feature owner; progressive structure; перенос responsibility | [Architecture](conventions/backend-architecture.md) |
+| TS vocabulary, domain literals, magic values | [Domain literals](conventions/backend-architecture.md#domain-literals-and-magic-values) |
 | Controller, DTO, route/status, validation/exception, публичная HTTP-семантика | [HTTP API](conventions/backend-http-api.md) |
 | Repository/data access; Prisma/schema/query, transaction, migration, atomic write | [Data](conventions/backend-data.md) |
 | Тесты или behavior с testing risk | [Testing](conventions/backend-testing.md) |
diff --git a/.ai/conventions/backend-architecture.md b/.ai/conventions/backend-architecture.md
index 9614aea..a3e16f1 100644
--- a/.ai/conventions/backend-architecture.md
+++ b/.ai/conventions/backend-architecture.md
@@ -203,6 +203,56 @@ protobuf units/nano conversion — T-Bank integration. Domain используе
 `money.types.ts`, а не Swagger DTO; это общая форма денег для карт и портфеля.
 Давай функциям предметные имена; не создавай глобальные `utils.ts`/`helpers.ts`.
 
+## Domain literals and magic values
+
+Finite business vocabulary must be modeled explicitly; incidental implementation
+literals stay inline. Это относится к error codes, statuses, operation/account/
+instrument/transaction types, permissions, roles, feature states и бизнес-режимам.
+
+Перед новым определением найди existing owner/type/value. В branching и comparisons
+используй символическое значение владельца; не повторяй raw domain literals.
+Храни словарь у domain/module/entity с соблюдением границ слоёв, без глобальной
+свалки `constants.ts`. Сохраняй принятый pattern; для нового project-owned словаря
+без подходящего аналога используй `as const` с derived union:
+
+```ts
+const BankErrorCode = {
+  InvalidDate: "BANK_INVALID_DATE",
+  ImmutableOperation: "BANK_IMMUTABLE_OPERATION",
+} as const;
+type BankErrorCode = (typeof BankErrorCode)[keyof typeof BankErrorCode];
+
+// Вместо code === "BANK_INVALID_DATE":
+if (code === BankErrorCode.InvalidDate) { /* existing handling */ }
+```
+
+Значимые numeric policies (timeout, retry, page size, threshold, coefficient)
+называй по смыслу и единицам: `REQUEST_TIMEOUT_MS`, `CACHE_TTL_SECONDS`,
+`MAX_RETRY_COUNT`, `PAGE_SIZE`. Оставляй inline UI labels в принятом месте,
+log messages, индексы, `index + 1`, `Math.max(value, 0)`, `page ?? 1`,
+`percentage * 100` и очевидные локальные детали без semantic benefit.
+При неясном owner/смысле оставь значение и укажи ограничение в review.
+
+Не мигрируй корректные existing enum/union styles массово. Не добавляй ради
+правила factories, registries, schemas, loaders, abstraction layers, dependencies,
+custom lint/AST rules, generation/validation scripts или тесты существования
+констант. Semantic review проверяет ownership, единое написание и неизменность
+wire values; обычные behavior tests проверяют поведение.
+
+OpenAPI enum metadata и runtime validation должны читать тот же vocabulary,
+что application/domain. Например, `BankOperationKind` принадлежит bank-cards/domain,
+а DTO получает допустимые значения через `Object.values(BankOperationKind)`.
+Frontend переиспользует generated OpenAPI types/values по возможностям генератора,
+а не определяет независимый backend-owned словарь. Внешние/generated enums
+сохраняй; generated Prisma/protocol code вручную не меняй.
+
+`@typescript-eslint/no-magic-numbers` включён как error; базовое ESLint rule
+отключено в пользу TS-версии. Исключения для очевидных чисел и их bigint форм,
+индексов, default values, enum/type declarations и readonly properties заданы
+в ESLint config. Test fixtures/expected values остаются inline, остальные lint
+правила продолжают действовать. Numeric policy получает предметное имя и единицы;
+semantic magic strings проверяются conventions/review без нового инструмента.
+
 ## Logging
 
 Единственный logger — nestjs-pino; application events используют существующий
diff --git a/eslint.config.mjs b/eslint.config.mjs
index 1f292a7..537b840 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -26,6 +26,43 @@ export default tseslint.config(
   },
   {
     rules: {
+      'no-magic-numbers': 'off',
+      '@typescript-eslint/no-magic-numbers': [
+        'error',
+        {
+          ignore: [
+            -60,
+            -24,
+            -10,
+            -2,
+            -1,
+            0,
+            1,
+            2,
+            10,
+            24,
+            60,
+            '-60n',
+            '-24n',
+            '-10n',
+            '-2n',
+            '-1n',
+            '0n',
+            '1n',
+            '2n',
+            '10n',
+            '24n',
+            '60n',
+          ],
+          ignoreArrayIndexes: true,
+          ignoreDefaultValues: true,
+          ignoreEnums: true,
+          ignoreNumericLiteralTypes: true,
+          ignoreReadonlyClassProperties: true,
+          ignoreTypeIndexes: true,
+          enforceConst: true,
+        },
+      ],
       '@typescript-eslint/no-explicit-any': 'off',
       '@typescript-eslint/no-non-null-assertion': 'error',
       'no-restricted-syntax': [
@@ -39,7 +76,11 @@ export default tseslint.config(
       ],
       '@typescript-eslint/no-floating-promises': 'warn',
       '@typescript-eslint/no-unsafe-argument': 'warn',
-      "prettier/prettier": ["error", { endOfLine: "auto" }],
+      'prettier/prettier': ['error', { endOfLine: 'auto' }],
     },
   },
+  {
+    files: ['**/*.spec.ts', 'test/**/*.ts'],
+    rules: { '@typescript-eslint/no-magic-numbers': 'off' },
+  },
 );
diff --git a/src/common/decorators/api-safe-error-response.decorator.ts b/src/common/decorators/api-safe-error-response.decorator.ts
index 3b97dca..f62ab49 100644
--- a/src/common/decorators/api-safe-error-response.decorator.ts
+++ b/src/common/decorators/api-safe-error-response.decorator.ts
@@ -1,4 +1,4 @@
-import { applyDecorators } from '@nestjs/common';
+import { HttpStatus, applyDecorators } from '@nestjs/common';
 import {
   ApiExtraModels,
   ApiProperty,
@@ -35,10 +35,13 @@ function problemResponse(status: number, description: string) {
 export function ApiProblemResponses(): MethodDecorator & ClassDecorator {
   return applyDecorators(
     ApiExtraModels(ProblemDetailsDto),
-    problemResponse(400, 'Invalid request'),
-    problemResponse(401, 'Authentication required'),
-    problemResponse(404, 'Resource not found'),
-    problemResponse(503, 'Upstream service unavailable'),
-    problemResponse(500, 'Internal server error'),
+    problemResponse(HttpStatus.BAD_REQUEST, 'Invalid request'),
+    problemResponse(HttpStatus.UNAUTHORIZED, 'Authentication required'),
+    problemResponse(HttpStatus.NOT_FOUND, 'Resource not found'),
+    problemResponse(
+      HttpStatus.SERVICE_UNAVAILABLE,
+      'Upstream service unavailable',
+    ),
+    problemResponse(HttpStatus.INTERNAL_SERVER_ERROR, 'Internal server error'),
   );
 }
diff --git a/src/common/logging/request-logging.middleware.ts b/src/common/logging/request-logging.middleware.ts
index 312559d..fdfaf04 100644
--- a/src/common/logging/request-logging.middleware.ts
+++ b/src/common/logging/request-logging.middleware.ts
@@ -1,3 +1,4 @@
+import { constants as httpStatus } from 'node:http2';
 import { Injectable, NestMiddleware } from '@nestjs/common';
 import type { NextFunction, Request, Response } from 'express';
 import { randomUUID } from 'node:crypto';
@@ -46,11 +47,11 @@ export class RequestLoggingMiddleware implements NestMiddleware {
           : {}),
       };
       const level =
-        response.statusCode >= 500
+        response.statusCode >= httpStatus.HTTP_STATUS_INTERNAL_SERVER_ERROR
           ? 'error'
-          : response.statusCode === 429 ||
-              response.statusCode === 401 ||
-              response.statusCode === 403
+          : response.statusCode === httpStatus.HTTP_STATUS_TOO_MANY_REQUESTS ||
+              response.statusCode === httpStatus.HTTP_STATUS_UNAUTHORIZED ||
+              response.statusCode === httpStatus.HTTP_STATUS_FORBIDDEN
             ? 'warn'
             : 'info';
       this.logger.event(level, 'http.request.completed', context);
diff --git a/src/common/time.ts b/src/common/time.ts
new file mode 100644
index 0000000..48deb5b
--- /dev/null
+++ b/src/common/time.ts
@@ -0,0 +1,2 @@
+export const MILLISECONDS_PER_SECOND = 1_000;
+export const MILLISECONDS_PER_DAY = 86_400_000;
diff --git a/src/config/env.validation.ts b/src/config/env.validation.ts
index ae8b187..a15f0c5 100644
--- a/src/config/env.validation.ts
+++ b/src/config/env.validation.ts
@@ -1,3 +1,8 @@
+const DEFAULT_PORT = 3000;
+const DEFAULT_TBANK_RATE_LIMIT_PER_SECOND = 5;
+const MAX_PORT = 65_535;
+const MIN_JWT_SECRET_LENGTH = 32;
+const TOKEN_KEY_BYTES = 32;
 export interface Environment {
   DATABASE_URL: string;
   FRONTEND_ORIGIN: string;
@@ -13,12 +18,14 @@ export interface Environment {
 export function validateEnv(config: Record<string, unknown>): Environment {
   const databaseUrl = config['DATABASE_URL'];
   const frontendOrigin = config['FRONTEND_ORIGIN'];
-  const port = config['PORT'] ?? 3000;
+  const port = config['PORT'] ?? DEFAULT_PORT;
   const jwtSecret = config['JWT_SECRET'];
   const tokenEncryptionKey = config['TOKEN_ENCRYPTION_KEY'];
   const tbankEndpoint =
     config['TBANK_GRPC_ENDPOINT'] ?? 'invest-public-api.tbank.ru:443';
-  const tbankRateLimit = config['TBANK_RATE_LIMIT_PER_SECOND'] ?? 5;
+  const tbankRateLimit =
+    config['TBANK_RATE_LIMIT_PER_SECOND'] ??
+    DEFAULT_TBANK_RATE_LIMIT_PER_SECOND;
   const tbankCaCertPath = config['TBANK_CA_CERT_PATH'];
   const logLevel = config['LOG_LEVEL'] ?? 'info';
 
@@ -47,18 +54,25 @@ export function validateEnv(config: Record<string, unknown>): Environment {
   }
 
   const parsedPort = Number(port);
-  if (!Number.isInteger(parsedPort) || parsedPort < 1 || parsedPort > 65535) {
+  if (
+    !Number.isInteger(parsedPort) ||
+    parsedPort < 1 ||
+    parsedPort > MAX_PORT
+  ) {
     throw new Error('PORT must be a valid port number');
   }
 
-  if (typeof jwtSecret !== 'string' || jwtSecret.length < 32) {
+  if (
+    typeof jwtSecret !== 'string' ||
+    jwtSecret.length < MIN_JWT_SECRET_LENGTH
+  ) {
     throw new Error('JWT_SECRET must be at least 32 characters long');
   }
 
   if (
     typeof tokenEncryptionKey !== 'string' ||
     !/^[A-Za-z0-9+/]+={0,2}$/.test(tokenEncryptionKey) ||
-    Buffer.from(tokenEncryptionKey, 'base64').length !== 32
+    Buffer.from(tokenEncryptionKey, 'base64').length !== TOKEN_KEY_BYTES
   ) {
     throw new Error(
       'TOKEN_ENCRYPTION_KEY must be a base64-encoded 32-byte key',
diff --git a/src/integrations/moex/moex.client.ts b/src/integrations/moex/moex.client.ts
index 925407c..85351e6 100644
--- a/src/integrations/moex/moex.client.ts
+++ b/src/integrations/moex/moex.client.ts
@@ -1,5 +1,8 @@
+import { constants as httpStatus } from 'node:http2';
 import { Injectable, ServiceUnavailableException } from '@nestjs/common';
 
+const FALLBACK_PAGE_SIZE = 100;
+
 const baseUrl = 'https://iss.moex.com/iss';
 const timeoutMs = 10_000;
 
@@ -121,8 +124,8 @@ export class MoexClient {
       if (!paginated) return rows;
       const cursorBlock = response[`${block}.cursor`];
       if (!cursorBlock) {
-        if (current.length < 100) return rows;
-        start += 100;
+        if (current.length < FALLBACK_PAGE_SIZE) return rows;
+        start += FALLBACK_PAGE_SIZE;
         continue;
       }
       const cursor = parseRows(cursorBlock)[0];
@@ -145,7 +148,7 @@ export class MoexClient {
       const response = await fetch(url, {
         signal: AbortSignal.timeout(timeoutMs),
       });
-      if (response.status === 404) return null;
+      if (response.status === httpStatus.HTTP_STATUS_NOT_FOUND) return null;
       if (!response.ok) throw new Error(`MOEX HTTP ${response.status}`);
       const body: unknown = await response.json();
       if (!body || typeof body !== 'object')
diff --git a/src/integrations/ncr/ncr-ratings.client.ts b/src/integrations/ncr/ncr-ratings.client.ts
index 6b40676..ff3e47d 100644
--- a/src/integrations/ncr/ncr-ratings.client.ts
+++ b/src/integrations/ncr/ncr-ratings.client.ts
@@ -2,6 +2,12 @@ import { Injectable, ServiceUnavailableException } from '@nestjs/common';
 import { load } from 'cheerio';
 import { LRUCache } from 'lru-cache';
 
+const REGISTRY_CACHE_TTL_MS = 21_600_000;
+const REQUEST_TIMEOUT_MS = 10_000;
+const COLUMN_COUNT = 6;
+const ISIN_COLUMN = 3;
+const DATE_COLUMN = 5;
+
 const registryUrl = 'https://ratings.ru/ratings/issues/';
 export type NcrRating = {
   agency: 'NCR';
@@ -18,7 +24,7 @@ export class NcrRatingsClient {
   private readonly cache = new LRUCache<
     string,
     Promise<Map<string, NcrRating>>
-  >({ max: 1, ttl: 6 * 60 * 60_000 });
+  >({ max: 1, ttl: REGISTRY_CACHE_TTL_MS });
 
   async rating(isin: string): Promise<NcrRating | null> {
     const key = isin.trim().toUpperCase();
@@ -38,7 +44,7 @@ export class NcrRatingsClient {
 
   private async registry(): Promise<Map<string, NcrRating>> {
     const response = await fetch(registryUrl, {
-      signal: AbortSignal.timeout(10_000),
+      signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS),
     });
     if (!response.ok) throw new Error('NCR unavailable');
     const $ = load(await response.text());
@@ -49,18 +55,18 @@ export class NcrRatingsClient {
       .get();
     if (
       table.length !== 1 ||
-      headings.length !== 6 ||
+      headings.length !== COLUMN_COUNT ||
       headings[2] !== 'Рейтинг' ||
-      headings[3] !== 'ISIN' ||
-      headings[5] !== 'Дата'
+      headings[ISIN_COLUMN] !== 'ISIN' ||
+      headings[DATE_COLUMN] !== 'Дата'
     )
       throw new Error('NCR registry changed');
     const observedAt = new Date().toISOString();
     const result = new Map<string, NcrRating>();
     table.find('tbody tr').each((_, row) => {
       const cells = $(row).find('td');
-      if (cells.length !== 6) throw new Error('NCR row changed');
-      const isin = cells.eq(3).text().trim().toUpperCase();
+      if (cells.length !== COLUMN_COUNT) throw new Error('NCR row changed');
+      const isin = cells.eq(ISIN_COLUMN).text().trim().toUpperCase();
       // Unassigned issues cannot safely be matched to a held instrument.
       if (!/^[A-Z]{2}[A-Z0-9]{9}\d$/.test(isin)) return;
       const raw = cells.eq(2).text().replace(/\s+/g, ' ').trim();
@@ -73,9 +79,9 @@ export class NcrRatingsClient {
       )
         throw new Error('NCR rating changed');
       const dateParts = /^(\d{2})\.(\d{2})\.(\d{4})$/.exec(
-        cells.eq(5).text().trim(),
+        cells.eq(DATE_COLUMN).text().trim(),
       );
-      const href = cells.eq(3).find('a').attr('href');
+      const href = cells.eq(ISIN_COLUMN).find('a').attr('href');
       if (!dateParts || !href || !/^\/ratings\/issues\/\d+\/$/.test(href))
         throw new Error('NCR identity missing');
       const date = `${dateParts[3]}-${dateParts[2]}-${dateParts[1]}`;
diff --git a/src/integrations/tbank/tbank-account.policy.ts b/src/integrations/tbank/tbank-account.policy.ts
index c84ccf9..22c3aec 100644
--- a/src/integrations/tbank/tbank-account.policy.ts
+++ b/src/integrations/tbank/tbank-account.policy.ts
@@ -1,3 +1,4 @@
+import { MILLISECONDS_PER_SECOND } from '../../common/time';
 import { TbankAccount } from './tbank.client';
 
 const accountTypes = {
@@ -51,7 +52,7 @@ export function accessibleTbankAccount(
 
 function openedOn(seconds: string | number | undefined): string | null {
   if (seconds === undefined) return null;
-  const date = new Date(Number(seconds) * 1000);
+  const date = new Date(Number(seconds) * MILLISECONDS_PER_SECOND);
   if (Number.isNaN(date.valueOf())) return null;
   return date.toISOString().slice(0, 10);
 }
diff --git a/src/integrations/tbank/tbank.client.ts b/src/integrations/tbank/tbank.client.ts
index a995d17..14f52d4 100644
--- a/src/integrations/tbank/tbank.client.ts
+++ b/src/integrations/tbank/tbank.client.ts
@@ -1,3 +1,4 @@
+import { MILLISECONDS_PER_SECOND } from '../../common/time';
 import {
   ChannelCredentials,
   Client,
@@ -28,6 +29,13 @@ import type {
   TbankShare,
 } from './tbank-market.types';
 
+const RATE_WINDOW_MS = 1_000;
+const METADATA_MAX_ATTEMPTS = 3;
+const RPC_MAX_ATTEMPTS = 2;
+const MAX_QUEUE_SIZE = 50;
+const METADATA_RETRY_DELAY_MS = 2_000;
+const RPC_RETRY_DELAY_MS = 1_000;
+
 const requestDeadlineMs = 15_000;
 
 type Unary<Request, Response> = (
@@ -134,7 +142,7 @@ class RateLimiter {
 
   private drain(): void {
     const now = Date.now();
-    if (now - this.windowStartedAt >= 1000) {
+    if (now - this.windowStartedAt >= RATE_WINDOW_MS) {
       this.windowStartedAt = now;
       this.starts = 0;
     }
@@ -145,7 +153,7 @@ class RateLimiter {
     if (this.waiting.length && this.starts === this.perSecond) {
       setTimeout(
         () => this.drain(),
-        Math.max(1, 1000 - (now - this.windowStartedAt)),
+        Math.max(1, RATE_WINDOW_MS - (now - this.windowStartedAt)),
       );
     }
   }
@@ -422,8 +430,12 @@ export class TbankClient {
       'getCandles',
       {
         instrumentId: uid,
-        from: { seconds: String(Math.floor(from.valueOf() / 1000)) },
-        to: { seconds: String(Math.floor(to.valueOf() / 1000)) },
+        from: {
+          seconds: String(Math.floor(from.valueOf() / MILLISECONDS_PER_SECOND)),
+        },
+        to: {
+          seconds: String(Math.floor(to.valueOf() / MILLISECONDS_PER_SECOND)),
+        },
         interval: 'CANDLE_INTERVAL_DAY',
         limit: 2400,
       },
@@ -456,10 +468,10 @@ export class TbankClient {
     request: object,
   ): Promise<Response> {
     const metadataCall = method === 'getInstrumentBy';
-    const maxAttempts = metadataCall ? 3 : 2;
+    const maxAttempts = metadataCall ? METADATA_MAX_ATTEMPTS : RPC_MAX_ATTEMPTS;
     for (let attempts = 1; attempts <= maxAttempts; attempts += 1) {
       const startedAt = performance.now();
-      const queueFull = this.queue.size >= 50;
+      const queueFull = this.queue.size >= MAX_QUEUE_SIZE;
       try {
         if (queueFull)
           throw new ServiceUnavailableException({ code: 'TBANK_UNAVAILABLE' });
@@ -492,7 +504,12 @@ export class TbankClient {
             durationMs: Math.round(performance.now() - startedAt),
           });
           await new Promise((resolve) =>
-            setTimeout(resolve, metadataCall ? attempts * 2000 : 1000),
+            setTimeout(
+              resolve,
+              metadataCall
+                ? attempts * METADATA_RETRY_DELAY_MS
+                : RPC_RETRY_DELAY_MS,
+            ),
           );
           continue;
         }
@@ -537,5 +554,5 @@ export class TbankClient {
 }
 
 function utcSeconds(date: string): number {
-  return Math.floor(Date.parse(`${date}T00:00:00Z`) / 1000);
+  return Math.floor(Date.parse(`${date}T00:00:00Z`) / MILLISECONDS_PER_SECOND);
 }
diff --git a/src/integrations/tbank/tbank.crypto.ts b/src/integrations/tbank/tbank.crypto.ts
index 23c5cf5..6eebe25 100644
--- a/src/integrations/tbank/tbank.crypto.ts
+++ b/src/integrations/tbank/tbank.crypto.ts
@@ -1,5 +1,7 @@
 import { createCipheriv, createDecipheriv, randomBytes } from 'node:crypto';
 
+const KEY_SIZE_BYTES = 32;
+
 const VERSION = 1;
 const NONCE_SIZE = 12;
 const TAG_SIZE = 16;
@@ -9,7 +11,8 @@ export class TbankCrypto {
 
   static fromBase64(key: string): TbankCrypto {
     const decoded = Buffer.from(key, 'base64');
-    if (decoded.length !== 32) throw new Error('Invalid token encryption key');
+    if (decoded.length !== KEY_SIZE_BYTES)
+      throw new Error('Invalid token encryption key');
     return new TbankCrypto(decoded);
   }
 
diff --git a/src/modules/auth/application/auth.service.ts b/src/modules/auth/application/auth.service.ts
index ecbdf5d..2e611c2 100644
--- a/src/modules/auth/application/auth.service.ts
+++ b/src/modules/auth/application/auth.service.ts
@@ -10,6 +10,9 @@ import { Session, User } from '../../../../generated/prisma/client';
 import { PrismaService } from '../../../prisma/prisma.service';
 import { AuthUser, RefreshPayload } from './auth.types';
 
+const PASSWORD_HASH_ROUNDS = 12;
+const REFRESH_TTL_MS = 604_800_000;
+
 const ACCESS_TTL = '15m';
 const REFRESH_TTL = '7d';
 const DUMMY_PASSWORD_HASH =
@@ -39,7 +42,7 @@ export class AuthService {
         data: {
           id: randomUUID(),
           email: normalizedEmail,
-          passwordHash: await bcrypt.hash(password, 12),
+          passwordHash: await bcrypt.hash(password, PASSWORD_HASH_ROUNDS),
         },
       });
     } catch (error) {
@@ -162,7 +165,7 @@ export class AuthService {
     );
     const data = {
       refreshTokenHash: this.hash(refreshToken),
-      expiresAt: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000),
+      expiresAt: new Date(Date.now() + REFRESH_TTL_MS),
     };
     if (expectedRefreshTokenHash) {
       const updated = await this.prisma.session.updateMany({
diff --git a/src/modules/auth/presentation/auth.controller.ts b/src/modules/auth/presentation/auth.controller.ts
index 4d35801..3b44ca6 100644
--- a/src/modules/auth/presentation/auth.controller.ts
+++ b/src/modules/auth/presentation/auth.controller.ts
@@ -3,6 +3,7 @@ import {
   Controller,
   Get,
   HttpCode,
+  HttpStatus,
   Post,
   Req,
   Res,
@@ -49,7 +50,7 @@ export class AuthController {
   constructor(private readonly auth: AuthService) {}
 
   @Post('register')
-  @HttpCode(200)
+  @HttpCode(HttpStatus.OK)
   @ApiOkResponse({ type: AuthenticationDto })
   async register(
     @Body() credentials: CredentialsDto,
@@ -62,7 +63,7 @@ export class AuthController {
   }
 
   @Post('login')
-  @HttpCode(200)
+  @HttpCode(HttpStatus.OK)
   @ApiOkResponse({ type: AuthenticationDto })
   async login(
     @Body() credentials: CredentialsDto,
@@ -75,7 +76,7 @@ export class AuthController {
   }
 
   @Post('refresh')
-  @HttpCode(200)
+  @HttpCode(HttpStatus.OK)
   @ApiOkResponse({ type: AuthenticationDto })
   async refresh(
     @Req() request: Request,
@@ -92,7 +93,7 @@ export class AuthController {
   }
 
   @Post('logout')
-  @HttpCode(204)
+  @HttpCode(HttpStatus.NO_CONTENT)
   @ApiNoContentResponse()
   async logout(
     @Req() request: Request,
diff --git a/src/modules/auth/presentation/auth.dto.ts b/src/modules/auth/presentation/auth.dto.ts
index fa30110..b2e25ec 100644
--- a/src/modules/auth/presentation/auth.dto.ts
+++ b/src/modules/auth/presentation/auth.dto.ts
@@ -7,20 +7,26 @@ import {
   ValidatorConstraint,
 } from 'class-validator';
 
+const MAX_EMAIL_LENGTH = 254;
+const ASCII_SPACE = 32;
+const ASCII_DELETE = 127;
+const MIN_PASSWORD_LENGTH = 12;
+const MAX_PASSWORD_BYTES = 72;
+
 @ValidatorConstraint({ name: 'email' })
 class EmailConstraint {
   validate(value: unknown): boolean {
     return (
       typeof value === 'string' &&
-      value.length <= 254 &&
+      value.length <= MAX_EMAIL_LENGTH &&
       value.split('@').length === 2 &&
       !value
         .split('')
         .some(
           (character) =>
             /\s/.test(character) ||
-            character.charCodeAt(0) < 32 ||
-            character.charCodeAt(0) === 127,
+            character.charCodeAt(0) < ASCII_SPACE ||
+            character.charCodeAt(0) === ASCII_DELETE,
         ) &&
       value.split('@').every(Boolean)
     );
@@ -33,7 +39,10 @@ class EmailConstraint {
 @ValidatorConstraint({ name: 'passwordBytes' })
 class PasswordBytesConstraint {
   validate(value: unknown): boolean {
-    return typeof value === 'string' && Buffer.byteLength(value, 'utf8') <= 72;
+    return (
+      typeof value === 'string' &&
+      Buffer.byteLength(value, 'utf8') <= MAX_PASSWORD_BYTES
+    );
   }
   defaultMessage(): string {
     return 'must not exceed 72 UTF-8 bytes';
@@ -49,9 +58,13 @@ export class CredentialsDto {
   @Validate(EmailConstraint)
   declare email: string;
 
-  @ApiProperty({ minLength: 12, maxLength: 72, example: 'a secure password' })
+  @ApiProperty({
+    minLength: MIN_PASSWORD_LENGTH,
+    maxLength: MAX_PASSWORD_BYTES,
+    example: 'a secure password',
+  })
   @IsString()
-  @MinLength(12)
+  @MinLength(MIN_PASSWORD_LENGTH)
   @Validate(PasswordBytesConstraint)
   declare password: string;
 }
diff --git a/src/modules/banking/bank-cards/application/bank-card-input.ts b/src/modules/banking/bank-cards/application/bank-card-input.ts
index 2fdf64d..e62f380 100644
--- a/src/modules/banking/bank-cards/application/bank-card-input.ts
+++ b/src/modules/banking/bank-cards/application/bank-card-input.ts
@@ -1,3 +1,7 @@
+import {
+  MAX_CARD_NAME_LENGTH,
+  MAX_OPERATION_DESCRIPTION_LENGTH,
+} from '../domain/bank-card-limits';
 import {
   BadRequestException,
   ConflictException,
@@ -13,7 +17,26 @@ import {
 import { isCalendarDate, moscowToday } from '../domain/bank-card.calculations';
 import { parseRubMoney } from '../domain/rub-money';
 
-export function fail(code = 'BANK_INVALID_INPUT'): never {
+export const BankErrorCode = {
+  InvalidInput: 'BANK_INVALID_INPUT',
+  VersionConflict: 'BANK_VERSION_CONFLICT',
+  NotFound: 'BANK_NOT_FOUND',
+  InvalidMoney: 'BANK_INVALID_MONEY',
+  InvalidDate: 'BANK_INVALID_DATE',
+  ImmutableOperation: 'BANK_IMMUTABLE_OPERATION',
+  InvalidRefund: 'BANK_INVALID_REFUND',
+  RefundLimit: 'BANK_REFUND_LIMIT',
+  DependentRefunds: 'BANK_DEPENDENT_REFUNDS',
+  IntentConflict: 'BANK_INTENT_CONFLICT',
+  OperationDeleted: 'BANK_OPERATION_DELETED',
+  CardArchived: 'BANK_CARD_ARCHIVED',
+  OpeningDateConflict: 'BANK_OPENING_DATE_CONFLICT',
+  WriteConflict: 'BANK_WRITE_CONFLICT',
+  DuplicateCategory: 'BANK_DUPLICATE_CATEGORY',
+} as const;
+export type BankErrorCode = (typeof BankErrorCode)[keyof typeof BankErrorCode];
+
+export function fail(code: BankErrorCode = BankErrorCode.InvalidInput): never {
   throw new BadRequestException({ code });
 }
 export function periodBounds(query: BankPeriodQueryDto) {
@@ -35,11 +58,13 @@ export function periodBounds(query: BankPeriodQueryDto) {
     return fail();
   return { from: query.from, to: query.to };
 }
-export function conflict(code = 'BANK_VERSION_CONFLICT'): never {
+export function conflict(
+  code: BankErrorCode = BankErrorCode.VersionConflict,
+): never {
   throw new ConflictException({ code });
 }
 export function missing(): never {
-  throw new NotFoundException({ code: 'BANK_NOT_FOUND' });
+  throw new NotFoundException({ code: BankErrorCode.NotFound });
 }
 export const fingerprint = (value: unknown) =>
   createHash('sha256')
@@ -56,16 +81,16 @@ export function amount(
   try {
     return parseRubMoney(value, positive);
   } catch {
-    return fail('BANK_INVALID_MONEY');
+    return fail(BankErrorCode.InvalidMoney);
   }
 }
 export function calendar(value: string) {
-  if (!isCalendarDate(value)) fail('BANK_INVALID_DATE');
+  if (!isCalendarDate(value)) fail(BankErrorCode.InvalidDate);
   return value;
 }
 export function currentDate(value: string) {
   calendar(value);
-  if (value > moscowToday()) fail('BANK_INVALID_DATE');
+  if (value > moscowToday()) fail(BankErrorCode.InvalidDate);
 }
 export function name(value: string, max: number) {
   if (typeof value !== 'string' || !value.trim() || value.trim().length > max)
@@ -74,7 +99,7 @@ export function name(value: string, max: number) {
 }
 export function cardInput(dto: CreateBankCardDto) {
   const bankName = dto.bankName?.trim() || null;
-  if (bankName && bankName.length > 100) fail();
+  if (bankName && bankName.length > MAX_CARD_NAME_LENGTH) fail();
   if (dto.lastFour != null && !/^\d{4}$/.test(dto.lastFour)) fail();
   if (
     dto.paymentSystem != null &&
@@ -83,7 +108,7 @@ export function cardInput(dto: CreateBankCardDto) {
     fail();
   return {
     ...(dto.paymentSystem == null ? {} : { paymentSystem: dto.paymentSystem }),
-    name: name(dto.name, 100),
+    name: name(dto.name, MAX_CARD_NAME_LENGTH),
     bankName,
     lastFour: dto.lastFour || null,
     openingBalanceKopecks: amount(dto.openingBalance),
@@ -93,7 +118,8 @@ export function cardInput(dto: CreateBankCardDto) {
 export function operationInput(dto: CreateBankOperationDto) {
   if (
     dto.description != null &&
-    (typeof dto.description !== 'string' || dto.description.length > 500)
+    (typeof dto.description !== 'string' ||
+      dto.description.length > MAX_OPERATION_DESCRIPTION_LENGTH)
   )
     fail();
   return {
diff --git a/src/modules/banking/bank-cards/application/bank-cards.service.ts b/src/modules/banking/bank-cards/application/bank-cards.service.ts
index c83f8be..356c5a0 100644
--- a/src/modules/banking/bank-cards/application/bank-cards.service.ts
+++ b/src/modules/banking/bank-cards/application/bank-cards.service.ts
@@ -11,6 +11,7 @@ import { rubMoney } from '../domain/rub-money';
 
 import {
   cardInput,
+  BankErrorCode,
   conflict,
   currentDate,
   fail,
@@ -71,7 +72,7 @@ export class BankCardsService {
       if (existing) {
         if (existing.userId !== userId) missing();
         if (existing.createFingerprint !== hash)
-          conflict('BANK_INTENT_CONFLICT');
+          conflict(BankErrorCode.IntentConflict);
         return this.cardView(tx, existing);
       }
       currentDate(input.openingDate);
@@ -110,7 +111,8 @@ export class BankCardsService {
       const financial =
         input.openingBalanceKopecks !== previous.openingBalanceKopecks ||
         input.openingDate !== previous.openingDate;
-      if (financial && previous.archivedAt) conflict('BANK_CARD_ARCHIVED');
+      if (financial && previous.archivedAt)
+        conflict(BankErrorCode.CardArchived);
       currentDate(input.openingDate);
       if (
         await tx.bankCardOperation.findFirst({
@@ -122,7 +124,7 @@ export class BankCardsService {
           },
         })
       )
-        fail('BANK_OPENING_DATE_CONFLICT');
+        fail(BankErrorCode.OpeningDateConflict);
       const changed = await tx.bankCard.updateMany({
         where: { id, userId, version: dto.version },
         data: {
diff --git a/src/modules/banking/bank-cards/application/bank-operations.service.ts b/src/modules/banking/bank-cards/application/bank-operations.service.ts
index 3296be7..9b6cabd 100644
--- a/src/modules/banking/bank-cards/application/bank-operations.service.ts
+++ b/src/modules/banking/bank-cards/application/bank-operations.service.ts
@@ -1,3 +1,4 @@
+import { BankOperationKind } from '../domain/bank-operation-kind';
 import { GoneException, Injectable } from '@nestjs/common';
 import {
   BankCardOperation,
@@ -6,6 +7,7 @@ import {
 import { PrismaService } from '../../../../prisma/prisma.service';
 import {
   BankOperationDto,
+  DEFAULT_BANK_PAGE_SIZE,
   BankOperationsQueryDto,
   BankPageQueryDto,
   CreateBankOperationDto,
@@ -14,6 +16,7 @@ import {
 import { rubMoney } from '../domain/rub-money';
 
 import {
+  BankErrorCode,
   conflict,
   currentDate,
   fail,
@@ -48,7 +51,7 @@ export class BankOperationsService {
         })
       : null;
     const refunds =
-      row.kind === 'expense' || source
+      row.kind === BankOperationKind.Expense || source
         ? await tx.bankCardOperation.findMany({
             where: {
               userId: row.userId,
@@ -70,7 +73,7 @@ export class BankOperationsService {
       originalExpenseId: row.originalExpenseId,
       amount: rubMoney(row.amountKopecks),
       availableRefund:
-        row.kind === 'expense' || source
+        row.kind === BankOperationKind.Expense || source
           ? rubMoney(
               (source?.amountKopecks ?? row.amountKopecks) -
                 refunds.reduce((sum, r) => sum + r.amountKopecks, 0n),
@@ -100,15 +103,15 @@ export class BankOperationsService {
         (id === input.cardId || id === input.targetCardId) &&
         input.date < card.openingDate
       )
-        fail('BANK_INVALID_DATE');
+        fail(BankErrorCode.InvalidDate);
     }
     if (
       old &&
       (old.kind !== input.kind ||
         old.originalExpenseId !== input.originalExpenseId)
     )
-      fail('BANK_IMMUTABLE_OPERATION');
-    if (input.kind === 'transfer') {
+      fail(BankErrorCode.ImmutableOperation);
+    if (input.kind === BankOperationKind.Transfer) {
       if (
         !input.targetCardId ||
         input.targetCardId === input.cardId ||
@@ -117,7 +120,7 @@ export class BankOperationsService {
       )
         fail();
     } else if (input.targetCardId) fail();
-    if (input.kind === 'expense') {
+    if (input.kind === BankOperationKind.Expense) {
       if (input.originalExpenseId) fail();
       if (!input.categoryId) {
         const category = await tx.expenseCategory.findUnique({
@@ -133,8 +136,9 @@ export class BankOperationsService {
       )
         missing();
     } else if (input.categoryId) fail();
-    if (input.kind !== 'refund' && input.originalExpenseId) fail();
-    if (input.kind === 'refund') {
+    if (input.kind !== BankOperationKind.Refund && input.originalExpenseId)
+      fail();
+    if (input.kind === BankOperationKind.Refund) {
       if (!input.originalExpenseId) fail();
       const source = await this.repository.operation(
         tx,
@@ -143,10 +147,10 @@ export class BankOperationsService {
       );
       if (
         source.deletedAt ||
-        source.kind !== 'expense' ||
+        source.kind !== BankOperationKind.Expense ||
         source.cardId !== input.cardId
       )
-        fail('BANK_INVALID_REFUND');
+        fail(BankErrorCode.InvalidRefund);
       if (
         (
           await tx.bankCardOperation.updateMany({
@@ -169,15 +173,15 @@ export class BankOperationsService {
           ...(old ? { id: { not: old.id } } : {}),
         },
       });
-      if (input.date < source.date) fail('BANK_INVALID_DATE');
+      if (input.date < source.date) fail(BankErrorCode.InvalidDate);
       if (
         refunds.reduce((sum, r) => sum + r.amountKopecks, 0n) +
           input.amountKopecks >
         source.amountKopecks
       )
-        conflict('BANK_REFUND_LIMIT');
+        conflict(BankErrorCode.RefundLimit);
     }
-    if (old?.kind === 'expense') {
+    if (old?.kind === BankOperationKind.Expense) {
       const refunds = await tx.bankCardOperation.findMany({
         where: { userId, originalExpenseId: old.id, deletedAt: null },
       });
@@ -188,7 +192,7 @@ export class BankOperationsService {
           refunds.reduce((sum, row) => sum + row.amountKopecks, 0n) >
             input.amountKopecks)
       )
-        conflict('BANK_DEPENDENT_REFUNDS');
+        conflict(BankErrorCode.DependentRefunds);
     }
   }
   createOperation(userId: string, dto: CreateBankOperationDto) {
@@ -201,9 +205,9 @@ export class BankOperationsService {
       if (existing) {
         if (existing.userId !== userId) missing();
         if (existing.createFingerprint !== hash)
-          conflict('BANK_INTENT_CONFLICT');
+          conflict(BankErrorCode.IntentConflict);
         if (existing.deletedAt)
-          throw new GoneException({ code: 'BANK_OPERATION_DELETED' });
+          throw new GoneException({ code: BankErrorCode.OperationDeleted });
         return this.operationView(tx, existing);
       }
       const input = { ...normalized };
@@ -265,12 +269,12 @@ export class BankOperationsService {
       if (row.targetCardId)
         await this.repository.card(tx, userId, row.targetCardId, true);
       if (
-        row.kind === 'expense' &&
+        row.kind === BankOperationKind.Expense &&
         (await tx.bankCardOperation.findFirst({
           where: { userId, originalExpenseId: id, deletedAt: null },
         }))
       )
-        conflict('BANK_DEPENDENT_REFUNDS');
+        conflict(BankErrorCode.DependentRefunds);
       if (row.originalExpenseId) {
         const source = await this.repository.operation(
           tx,
@@ -310,14 +314,14 @@ export class BankOperationsService {
     return this.prisma.$transaction(async (tx) => {
       await this.repository.card(tx, userId, id);
       const page = query.page ?? 1,
-        limit = query.limit ?? 50;
+        limit = query.limit ?? DEFAULT_BANK_PAGE_SIZE;
       const where: Prisma.BankCardOperationWhereInput = {
         userId,
         deletedAt: null,
         OR: [{ cardId: id }, { targetCardId: id }],
         ...(period
           ? { date: { gte: period.from, lte: period.to } }
-          : { kind: 'expense' }),
+          : { kind: BankOperationKind.Expense }),
       };
       const total = await tx.bankCardOperation.count({ where });
       const rows = await tx.bankCardOperation.findMany({
diff --git a/src/modules/banking/bank-cards/application/expense-categories.service.ts b/src/modules/banking/bank-cards/application/expense-categories.service.ts
index 8c44a29..f110154 100644
--- a/src/modules/banking/bank-cards/application/expense-categories.service.ts
+++ b/src/modules/banking/bank-cards/application/expense-categories.service.ts
@@ -1,3 +1,4 @@
+import { MAX_CATEGORY_NAME_LENGTH } from '../domain/bank-card-limits';
 import { Injectable } from '@nestjs/common';
 import { randomUUID } from 'node:crypto';
 import { PrismaService } from '../../../../prisma/prisma.service';
@@ -24,7 +25,7 @@ export class ExpenseCategoriesService {
     }));
   }
   createCategory(userId: string, value: string) {
-    const label = name(value, 80);
+    const label = name(value, MAX_CATEGORY_NAME_LENGTH);
     return this.repository.write(async (tx) => {
       await this.repository.seed(tx, userId);
       const row = await tx.expenseCategory.create({
@@ -44,7 +45,7 @@ export class ExpenseCategoriesService {
     });
   }
   updateCategory(userId: string, id: string, value: string, version: number) {
-    const label = name(value, 80);
+    const label = name(value, MAX_CATEGORY_NAME_LENGTH);
     return this.repository.write(async (tx) => {
       const row = await tx.expenseCategory.findFirst({ where: { id, userId } });
       if (!row) missing();
diff --git a/src/modules/banking/bank-cards/domain/bank-card-limits.ts b/src/modules/banking/bank-cards/domain/bank-card-limits.ts
new file mode 100644
index 0000000..9483b9d
--- /dev/null
+++ b/src/modules/banking/bank-cards/domain/bank-card-limits.ts
@@ -0,0 +1,3 @@
+export const MAX_CARD_NAME_LENGTH = 100;
+export const MAX_CATEGORY_NAME_LENGTH = 80;
+export const MAX_OPERATION_DESCRIPTION_LENGTH = 500;
diff --git a/src/modules/banking/bank-cards/domain/bank-card.calculations.ts b/src/modules/banking/bank-cards/domain/bank-card.calculations.ts
index d727ff5..4ee045a 100644
--- a/src/modules/banking/bank-cards/domain/bank-card.calculations.ts
+++ b/src/modules/banking/bank-cards/domain/bank-card.calculations.ts
@@ -1,3 +1,6 @@
+import { BankOperationKind } from './bank-operation-kind';
+
+const ISO_MONTH_LENGTH = 7;
 export function moscowToday(now = new Date()): string {
   return new Intl.DateTimeFormat('en-CA', {
     timeZone: 'Europe/Moscow',
@@ -30,12 +33,21 @@ export function bankBalance(
   let balance = opening;
   for (const operation of operations) {
     if (operation.cardId === cardId) {
-      if (operation.kind === 'expense' || operation.kind === 'transfer')
+      if (
+        operation.kind === BankOperationKind.Expense ||
+        operation.kind === BankOperationKind.Transfer
+      )
         balance -= operation.amountKopecks;
-      else if (operation.kind === 'topup' || operation.kind === 'refund')
+      else if (
+        operation.kind === BankOperationKind.Topup ||
+        operation.kind === BankOperationKind.Refund
+      )
         balance += operation.amountKopecks;
     }
-    if (operation.kind === 'transfer' && operation.targetCardId === cardId)
+    if (
+      operation.kind === BankOperationKind.Transfer &&
+      operation.targetCardId === cardId
+    )
       balance += operation.amountKopecks;
   }
   return balance;
@@ -60,13 +72,23 @@ export function bankSummary(
   for (const operation of operations) {
     if (
       typeof period === 'string'
-        ? operation.date.slice(0, 7) !== period
+        ? operation.date.slice(0, ISO_MONTH_LENGTH) !== period
         : operation.date < period.from || operation.date > period.to
     )
       continue;
-    if (operation.kind !== 'expense' && operation.kind !== 'refund') continue;
-    const expense = operation.kind === 'expense' ? operation.amountKopecks : 0n;
-    const refund = operation.kind === 'refund' ? operation.amountKopecks : 0n;
+    if (
+      operation.kind !== BankOperationKind.Expense &&
+      operation.kind !== BankOperationKind.Refund
+    )
+      continue;
+    const expense =
+      operation.kind === BankOperationKind.Expense
+        ? operation.amountKopecks
+        : 0n;
+    const refund =
+      operation.kind === BankOperationKind.Refund
+        ? operation.amountKopecks
+        : 0n;
     expenses += expense;
     refunds += refund;
     if (operation.categoryId !== null) {
diff --git a/src/modules/banking/bank-cards/domain/bank-operation-kind.ts b/src/modules/banking/bank-cards/domain/bank-operation-kind.ts
new file mode 100644
index 0000000..28454d3
--- /dev/null
+++ b/src/modules/banking/bank-cards/domain/bank-operation-kind.ts
@@ -0,0 +1,8 @@
+export const BankOperationKind = {
+  Expense: 'expense',
+  Topup: 'topup',
+  Transfer: 'transfer',
+  Refund: 'refund',
+} as const;
+export type BankOperationKind =
+  (typeof BankOperationKind)[keyof typeof BankOperationKind];
diff --git a/src/modules/banking/bank-cards/domain/rub-money.ts b/src/modules/banking/bank-cards/domain/rub-money.ts
index 5113565..2bb1b67 100644
--- a/src/modules/banking/bank-cards/domain/rub-money.ts
+++ b/src/modules/banking/bank-cards/domain/rub-money.ts
@@ -1,6 +1,9 @@
 import { decimalFromString, formatDecimal } from '../../../../common/decimal';
 import type { Money } from '../../../../common/money.types';
 
+const MIN_KOPECKS = -9_223_372_036_854_775_808n;
+const MAX_KOPECKS = 9_223_372_036_854_775_807n;
+
 export function parseRubMoney(money: Money, positive = false): bigint {
   if (
     money?.currency !== 'RUB' ||
@@ -12,7 +15,7 @@ export function parseRubMoney(money: Money, positive = false): bigint {
   if (amount.scale > 2)
     throw new RangeError('RUB money supports at most two decimal places');
   const kopecks = amount.value * 10n ** BigInt(2 - amount.scale);
-  if (kopecks < -(2n ** 63n) || kopecks > 2n ** 63n - 1n)
+  if (kopecks < MIN_KOPECKS || kopecks > MAX_KOPECKS)
     throw new RangeError('RUB money is outside the signed 64-bit range');
   if (positive && kopecks <= 0n)
     throw new RangeError('Operation amount must be positive');
diff --git a/src/modules/banking/bank-cards/infrastructure/bank-cards.repository.ts b/src/modules/banking/bank-cards/infrastructure/bank-cards.repository.ts
index 98ef256..48fab86 100644
--- a/src/modules/banking/bank-cards/infrastructure/bank-cards.repository.ts
+++ b/src/modules/banking/bank-cards/infrastructure/bank-cards.repository.ts
@@ -1,10 +1,18 @@
+import { BankOperationKind } from '../domain/bank-operation-kind';
 import { Injectable } from '@nestjs/common';
 import { randomUUID } from 'node:crypto';
 import { Prisma } from '../../../../../generated/prisma/client';
 import { PrismaService } from '../../../../prisma/prisma.service';
 
-import { conflict, missing } from '../application/bank-card-input';
+import {
+  BankErrorCode,
+  conflict,
+  missing,
+} from '../application/bank-card-input';
 type Tx = Prisma.TransactionClient;
+const TRANSACTION_MAX_WAIT_MS = 10_000;
+const TRANSACTION_TIMEOUT_MS = 15_000;
+const MAX_WRITE_RETRY_COUNT = 2;
 const seeds = [
   'Продукты',
   'Кафе',
@@ -23,8 +31,8 @@ export class BankCardsRepository {
     for (let attempt = 0; ; attempt++) {
       try {
         return await this.prisma.$transaction(run, {
-          maxWait: 10000,
-          timeout: 15000,
+          maxWait: TRANSACTION_MAX_WAIT_MS,
+          timeout: TRANSACTION_TIMEOUT_MS,
         });
       } catch (error) {
         const code =
@@ -36,9 +44,10 @@ export class BankCardsRepository {
           code === 'P2028' ||
           (error instanceof Error &&
             /SQLITE_BUSY|database is locked/.test(error.message));
-        if ((busy || code === 'P2002') && attempt < 2) continue;
-        if (busy) conflict('BANK_WRITE_CONFLICT');
-        if (code === 'P2002') conflict('BANK_DUPLICATE_CATEGORY');
+        if ((busy || code === 'P2002') && attempt < MAX_WRITE_RETRY_COUNT)
+          continue;
+        if (busy) conflict(BankErrorCode.WriteConflict);
+        if (code === 'P2002') conflict(BankErrorCode.DuplicateCategory);
         throw error;
       }
     }
@@ -46,7 +55,7 @@ export class BankCardsRepository {
   async card(tx: Tx, userId: string, id: string, active = false) {
     const card = await tx.bankCard.findFirst({ where: { id, userId } });
     if (!card) return missing();
-    if (active && card.archivedAt) conflict('BANK_CARD_ARCHIVED');
+    if (active && card.archivedAt) conflict(BankErrorCode.CardArchived);
     return card;
   }
   async operation(tx: Tx, userId: string, id: string) {
@@ -56,7 +65,7 @@ export class BankCardsRepository {
   }
   async seed(tx: Tx, userId: string) {
     for (const [index, label] of seeds.entries()) {
-      const seedKey = index === 8 ? 'other' : String(index);
+      const seedKey = index === seeds.length - 1 ? 'other' : String(index);
       if (
         !(await tx.expenseCategory.findUnique({
           where: { userId_seedKey: { userId, seedKey } },
@@ -85,7 +94,7 @@ export class BankCardsRepository {
           userId,
           deletedAt: null,
           date: { gte: period.from, lte: period.to },
-          kind: { in: ['expense', 'refund'] },
+          kind: { in: [BankOperationKind.Expense, BankOperationKind.Refund] },
           ...(cardId ? { cardId } : {}),
         },
         include: { originalExpense: { select: { categoryId: true } } },
diff --git a/src/modules/banking/bank-cards/presentation/bank-card.dto.ts b/src/modules/banking/bank-cards/presentation/bank-card.dto.ts
index 5374707..bb23f56 100644
--- a/src/modules/banking/bank-cards/presentation/bank-card.dto.ts
+++ b/src/modules/banking/bank-cards/presentation/bank-card.dto.ts
@@ -1,3 +1,9 @@
+import {
+  MAX_CARD_NAME_LENGTH,
+  MAX_CATEGORY_NAME_LENGTH,
+  MAX_OPERATION_DESCRIPTION_LENGTH,
+} from '../domain/bank-card-limits';
+import { BankOperationKind } from '../domain/bank-operation-kind';
 import {
   ApiProperty,
   ApiPropertyOptional,
@@ -24,16 +30,13 @@ import {
 } from 'class-validator';
 import { MoneyDto } from '../../../../common/money.dto';
 
+export const DEFAULT_BANK_PAGE_SIZE = 50;
+const MAX_BANK_PAGE_SIZE = 100;
+
 const trim = ({ value }: { value: unknown }) =>
   typeof value === 'string' ? value.trim() : value;
 export const bankPaymentSystems = ['mir', 'visa', 'mastercard'] as const;
-export const bankOperationKinds = [
-  'expense',
-  'topup',
-  'transfer',
-  'refund',
-] as const;
-export type BankOperationKind = (typeof bankOperationKinds)[number];
+const bankOperationKinds = Object.values(BankOperationKind);
 export class RubMoneyInputDto {
   @ApiProperty({ enum: ['RUB'] }) @IsIn(['RUB']) declare currency: string;
   @ApiProperty({ pattern: '^-?[0-9]+(\\.[0-9]{1,2})?$' })
@@ -43,17 +46,21 @@ export class RubMoneyInputDto {
 }
 export class CreateBankCardDto {
   @ApiProperty({ format: 'uuid' }) @IsUUID() declare id: string;
-  @ApiProperty({ minLength: 1, maxLength: 100 })
+  @ApiProperty({ minLength: 1, maxLength: MAX_CARD_NAME_LENGTH })
   @Transform(trim)
   @IsString()
   @MinLength(1)
-  @MaxLength(100)
+  @MaxLength(MAX_CARD_NAME_LENGTH)
   declare name: string;
-  @ApiPropertyOptional({ type: String, nullable: true, maxLength: 100 })
+  @ApiPropertyOptional({
+    type: String,
+    nullable: true,
+    maxLength: MAX_CARD_NAME_LENGTH,
+  })
   @IsOptional()
   @Transform(trim)
   @IsString()
-  @MaxLength(100)
+  @MaxLength(MAX_CARD_NAME_LENGTH)
   bankName?: string | null;
   @ApiPropertyOptional({ type: String, nullable: true, pattern: '^[0-9]{4}$' })
   @IsOptional()
@@ -84,11 +91,11 @@ export class UpdateBankCardDto extends PartialType(
   archived?: boolean;
 }
 export class CategoryNameDto {
-  @ApiProperty({ minLength: 1, maxLength: 80 })
+  @ApiProperty({ minLength: 1, maxLength: MAX_CATEGORY_NAME_LENGTH })
   @Transform(trim)
   @IsString()
   @MinLength(1)
-  @MaxLength(80)
+  @MaxLength(MAX_CATEGORY_NAME_LENGTH)
   declare name: string;
 }
 export class UpdateExpenseCategoryDto extends CategoryNameDto {
@@ -121,10 +128,10 @@ export class CreateBankOperationDto {
   @IsString()
   @Matches(/^\d{4}-\d{2}-\d{2}$/)
   declare date: string;
-  @ApiPropertyOptional({ maxLength: 500 })
+  @ApiPropertyOptional({ maxLength: MAX_OPERATION_DESCRIPTION_LENGTH })
   @ValidateIf((_object, value: unknown) => value !== undefined)
   @IsString()
-  @MaxLength(500)
+  @MaxLength(MAX_OPERATION_DESCRIPTION_LENGTH)
   description?: string;
 }
 export class UpdateBankOperationDto extends PartialType(
@@ -146,12 +153,16 @@ export class BankPageQueryDto {
   @IsInt()
   @Min(1)
   page?: number;
-  @ApiPropertyOptional({ minimum: 1, maximum: 100, default: 50 })
+  @ApiPropertyOptional({
+    minimum: 1,
+    maximum: MAX_BANK_PAGE_SIZE,
+    default: DEFAULT_BANK_PAGE_SIZE,
+  })
   @IsOptional()
   @Type(() => Number)
   @IsInt()
   @Min(1)
-  @Max(100)
+  @Max(MAX_BANK_PAGE_SIZE)
   limit?: number;
 }
 export class BankPeriodQueryDto {
diff --git a/src/modules/banking/bank-cards/presentation/bank-cards.controller.ts b/src/modules/banking/bank-cards/presentation/bank-cards.controller.ts
index 91d6353..e484e23 100644
--- a/src/modules/banking/bank-cards/presentation/bank-cards.controller.ts
+++ b/src/modules/banking/bank-cards/presentation/bank-cards.controller.ts
@@ -4,6 +4,7 @@ import {
   Delete,
   Get,
   HttpCode,
+  HttpStatus,
   Param,
   Patch,
   Post,
@@ -143,7 +144,7 @@ export class BankCardsController {
     return this.operations.updateOperation(req.user.sub, id, body);
   }
   @Delete('operations/:id')
-  @HttpCode(204)
+  @HttpCode(HttpStatus.NO_CONTENT)
   @ApiNoContentResponse()
   deleteOperation(
     @Req() req: AuthRequest,
diff --git a/src/modules/investments/income/income-period.ts b/src/modules/investments/income/income-period.ts
index 72b35bd..e6e242e 100644
--- a/src/modules/investments/income/income-period.ts
+++ b/src/modules/investments/income/income-period.ts
@@ -1,3 +1,4 @@
+import { MILLISECONDS_PER_DAY } from '../../../common/time';
 import { BadRequestException } from '@nestjs/common';
 import {
   DateOnlyRange,
@@ -6,6 +7,12 @@ import {
   utcDate,
 } from '../investment-calendar';
 
+const DAILY_BUCKET_MAX_DAYS = 45;
+const WEEKLY_BUCKET_MAX_DAYS = 180;
+const DAYS_PER_WEEK = 7;
+const ISO_MONTH_LENGTH = 7;
+const ISO_YEAR_LENGTH = 4;
+
 export type IncomeBucketGranularity = 'day' | 'week' | 'month';
 
 export function planIncomePeriod(
@@ -36,9 +43,9 @@ export function planIncomePeriod(
     previous,
     yearAgo: yearAgoRange,
     granularity:
-      rangeDays(selected) <= 45
+      rangeDays(selected) <= DAILY_BUCKET_MAX_DAYS
         ? 'day'
-        : rangeDays(selected) <= 180
+        : rangeDays(selected) <= WEEKLY_BUCKET_MAX_DAYS
           ? 'week'
           : 'month',
   };
@@ -53,11 +60,19 @@ export function rangeBuckets(
   const buckets: DateOnlyRange[] = [];
   let cursor =
     granularity === 'week'
-      ? addDays(range.from, -((utcDate(range.from).getUTCDay() + 6) % 7))
-      : `${range.from.slice(0, 7)}-01`;
+      ? addDays(
+          range.from,
+          -(
+            (utcDate(range.from).getUTCDay() + DAYS_PER_WEEK - 1) %
+            DAYS_PER_WEEK
+          ),
+        )
+      : `${range.from.slice(0, ISO_MONTH_LENGTH)}-01`;
   while (cursor <= range.to) {
     const end =
-      granularity === 'week' ? addDays(cursor, 6) : endOfMonth(cursor);
+      granularity === 'week'
+        ? addDays(cursor, DAYS_PER_WEEK - 1)
+        : endOfMonth(cursor);
     buckets.push({
       from: cursor < range.from ? range.from : cursor,
       to: end > range.to ? range.to : end,
@@ -71,7 +86,7 @@ export function rangeDays(range: DateOnlyRange): number {
   return (
     Math.round(
       (utcDate(range.to).valueOf() - utcDate(range.from).valueOf()) /
-        86_400_000,
+        MILLISECONDS_PER_DAY,
     ) + 1
   );
 }
@@ -100,7 +115,7 @@ function dates(range: DateOnlyRange): string[] {
 }
 
 function firstOfMonth(value: string): string {
-  return `${value.slice(0, 7)}-01`;
+  return `${value.slice(0, ISO_MONTH_LENGTH)}-01`;
 }
 
 function endOfMonth(value: string): string {
@@ -126,7 +141,7 @@ function shiftDays(range: DateOnlyRange, days: number): DateOnlyRange {
 function yearAgo(range: DateOnlyRange): DateOnlyRange | null {
   const shift = (value: string) => {
     const [year, month, day] = dateParts(value);
-    const result = `${String(year - 1).padStart(4, '0')}-${String(month).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
+    const result = `${String(year - 1).padStart(ISO_YEAR_LENGTH, '0')}-${String(month).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
     return utcDate(result).toISOString().slice(0, 10) === result
       ? result
       : null;
diff --git a/src/modules/investments/instruments/application/instrument-market.ts b/src/modules/investments/instruments/application/instrument-market.ts
index 8bdf05b..a74e55e 100644
--- a/src/modules/investments/instruments/application/instrument-market.ts
+++ b/src/modules/investments/instruments/application/instrument-market.ts
@@ -1,16 +1,21 @@
+import { MILLISECONDS_PER_SECOND } from '../../../../common/time';
 import { ServiceUnavailableException } from '@nestjs/common';
 import type {
   TbankCandle,
   TbankTimestamp,
 } from '../../../../integrations/tbank/tbank.api';
+
+const MOSCOW_OFFSET_MS = 10_800_000;
 export function timestamp(value?: TbankTimestamp): string | null {
   const seconds = Number(value?.seconds);
   return Number.isFinite(seconds) && seconds > 0
-    ? new Date(seconds * 1000).toISOString()
+    ? new Date(seconds * MILLISECONDS_PER_SECOND).toISOString()
     : null;
 }
 export function moscowDay(iso: string): string {
-  return new Date(Date.parse(iso) + 3 * 3_600_000).toISOString().slice(0, 10);
+  return new Date(Date.parse(iso) + MOSCOW_OFFSET_MS)
+    .toISOString()
+    .slice(0, 10);
 }
 export function previousClose(
   candles: TbankCandle[],
diff --git a/src/modules/investments/instruments/application/instrument-position.ts b/src/modules/investments/instruments/application/instrument-position.ts
index c6479dd..2c84ff4 100644
--- a/src/modules/investments/instruments/application/instrument-position.ts
+++ b/src/modules/investments/instruments/application/instrument-position.ts
@@ -13,6 +13,9 @@ import {
 } from '../../portfolio/portfolio.api';
 import { StockPositionDto } from '../stocks/presentation/stock.dto';
 
+const PRICE_DECIMAL_PLACES = 9;
+const RETURN_PERCENT_DECIMAL_PLACES = 6;
+
 export function instrumentPosition(
   portfolio: PortfolioDto,
   uid: string,
@@ -41,7 +44,11 @@ export function instrumentPosition(
         ? {
             currency: totalCost.currency,
             value: formatDecimal(
-              divide(decimalFromString(totalCost.value), quantity, 9),
+              divide(
+                decimalFromString(totalCost.value),
+                quantity,
+                PRICE_DECIMAL_PLACES,
+              ),
             ),
           }
         : null,
@@ -103,7 +110,7 @@ function percent(
     divide(
       multiply(decimalFromString(result.value), decimalFromString('100')),
       decimalFromString(base.value),
-      6,
+      RETURN_PERCENT_DECIMAL_PLACES,
     ),
   );
 }
diff --git a/src/modules/investments/instruments/bonds/application/bond-catalog.service.ts b/src/modules/investments/instruments/bonds/application/bond-catalog.service.ts
index a69d169..2b0db17 100644
--- a/src/modules/investments/instruments/bonds/application/bond-catalog.service.ts
+++ b/src/modules/investments/instruments/bonds/application/bond-catalog.service.ts
@@ -19,6 +19,8 @@ import { BondDto, BondSearchResultDto } from '../presentation/bond.dto';
 type IdentifiedBond = TbankBond & { uid: string };
 
 import { money } from '../infrastructure/bond-money.mapper';
+
+const SEARCH_RESULTS_LIMIT = 30;
 @Injectable()
 export class BondCatalogService {
   private readonly cache = new LRUCache<string, Promise<object>>({
@@ -33,7 +35,7 @@ export class BondCatalogService {
     return this.cached(userId, `search:${query}`, async (connection) => {
       const { token } = connection;
       const found = await this.tbank.findBonds(token, query);
-      const bonds = selectBonds(found, query).slice(0, 30);
+      const bonds = selectBonds(found, query).slice(0, SEARCH_RESULTS_LIMIT);
       if (!bonds.length) return [];
       // Batch prices and share metadata with detail sections. Resolve readable
       // aliases only when an issue is opened, not for every search result.
diff --git a/src/modules/investments/instruments/bonds/application/bond-income.service.ts b/src/modules/investments/instruments/bonds/application/bond-income.service.ts
index 5033a14..beafae8 100644
--- a/src/modules/investments/instruments/bonds/application/bond-income.service.ts
+++ b/src/modules/investments/instruments/bonds/application/bond-income.service.ts
@@ -27,6 +27,10 @@ import {
 import { BondMarketService } from './bond-market.service';
 import { money } from '../infrastructure/bond-money.mapper';
 import { BondCatalogService } from './bond-catalog.service';
+
+const ISO_YEAR_LENGTH = 4;
+const INCOME_HISTORY_YEARS = 5;
+const COUPON_YIELD_DECIMAL_PLACES = 4;
 @Injectable()
 export class BondIncomeService {
   constructor(
@@ -42,8 +46,8 @@ export class BondIncomeService {
       const instrument = await this.catalog.bond(userId, connection, uid);
       const { ticker, isin, classCode } = instrument;
       const today = moscowDay(new Date().toISOString());
-      const from = `${Number(today.slice(0, 4)) - 5}${today.slice(4)}`;
-      const to = `${Number(today.slice(0, 4)) + 1}${today.slice(4)}`;
+      const from = `${Number(today.slice(0, ISO_YEAR_LENGTH)) - INCOME_HISTORY_YEARS}${today.slice(ISO_YEAR_LENGTH)}`;
+      const to = `${Number(today.slice(0, ISO_YEAR_LENGTH)) + 1}${today.slice(ISO_YEAR_LENGTH)}`;
       const unavailable: string[] = [];
       const [events, quote, effectiveYield, creditRating] = await Promise.all([
         optional(
@@ -94,7 +98,7 @@ export class BondIncomeService {
                   decimalFromString(String(couponPeriodDays)),
                   decimalFromString(clean.value),
                 ),
-                4,
+                COUPON_YIELD_DECIMAL_PLACES,
               ),
             )
           : null;
@@ -137,8 +141,8 @@ export class BondIncomeService {
     return this.catalog.cached(userId, `coupons:${uid}`, async (connection) => {
       await this.catalog.bond(userId, connection, uid);
       const today = moscowDay(new Date().toISOString());
-      const from = `${Number(today.slice(0, 4)) - 5}${today.slice(4)}`;
-      const to = `${Number(today.slice(0, 4)) + 1}${today.slice(4)}`;
+      const from = `${Number(today.slice(0, ISO_YEAR_LENGTH)) - INCOME_HISTORY_YEARS}${today.slice(ISO_YEAR_LENGTH)}`;
+      const to = `${Number(today.slice(0, ISO_YEAR_LENGTH)) + 1}${today.slice(ISO_YEAR_LENGTH)}`;
       const unavailable: string[] = [];
       const [events, position] = await Promise.all([
         this.couponEvents(userId, connection, uid, from, to),
diff --git a/src/modules/investments/instruments/bonds/application/bond-market.service.ts b/src/modules/investments/instruments/bonds/application/bond-market.service.ts
index 30f8abd..db7a57b 100644
--- a/src/modules/investments/instruments/bonds/application/bond-market.service.ts
+++ b/src/modules/investments/instruments/bonds/application/bond-market.service.ts
@@ -24,6 +24,12 @@ const dayMs = 86_400_000;
 
 import { money } from '../infrastructure/bond-money.mapper';
 import { BondCatalogService } from './bond-catalog.service';
+
+const PREVIOUS_CLOSE_LOOKBACK_DAYS = 20;
+const HALF_YEAR_MONTHS = 6;
+const YEAR_MONTHS = 12;
+const CANDLE_WINDOW_DAYS = 365;
+const PRICE_DECIMAL_PLACES = 9;
 @Injectable()
 export class BondMarketService {
   constructor(
@@ -66,7 +72,7 @@ export class BondMarketService {
                     decimalFromString(nominal.value),
                   ),
                   decimalFromString('100'),
-                  9,
+                  PRICE_DECIMAL_PLACES,
                 ),
               ),
             }
@@ -90,7 +96,9 @@ export class BondMarketService {
                 await this.tbank.getCandles(
                   token,
                   uid,
-                  new Date(Date.parse(priceAt) - 20 * dayMs),
+                  new Date(
+                    Date.parse(priceAt) - PREVIOUS_CLOSE_LOOKBACK_DAYS * dayMs,
+                  ),
                   new Date(priceAt),
                 ),
                 priceAt,
@@ -134,7 +142,11 @@ export class BondMarketService {
         const from = new Date(to);
         from.setUTCMonth(
           from.getUTCMonth() -
-            (period === 'month' ? 1 : period === 'halfYear' ? 6 : 12),
+            (period === 'month'
+              ? 1
+              : period === 'halfYear'
+                ? HALF_YEAR_MONTHS
+                : YEAR_MONTHS),
         );
         if (period === 'all') {
           if (!historyFrom)
@@ -147,7 +159,10 @@ export class BondMarketService {
         const collected = new Map<string, BondCandlesDto['candles'][number]>();
         // Conservative one-year windows also work with older deployed RPC limits.
         for (let start = from.valueOf(); start < to.valueOf();) {
-          const end = Math.min(start + 365 * dayMs, to.valueOf());
+          const end = Math.min(
+            start + CANDLE_WINDOW_DAYS * dayMs,
+            to.valueOf(),
+          );
           for (const candle of await this.tbank.getCandles(
             token,
             uid,
diff --git a/src/modules/investments/instruments/stocks/application/stock-catalog.service.ts b/src/modules/investments/instruments/stocks/application/stock-catalog.service.ts
index 0455a76..a41aa84 100644
--- a/src/modules/investments/instruments/stocks/application/stock-catalog.service.ts
+++ b/src/modules/investments/instruments/stocks/application/stock-catalog.service.ts
@@ -15,6 +15,8 @@ import { decimal } from '../../../../../integrations/tbank/decimal';
 import { optional, timestamp } from '../../application/instrument-market';
 import { StockDto, StockSearchResultDto } from '../presentation/stock.dto';
 
+const SEARCH_RESULTS_LIMIT = 30;
+
 type IdentifiedShare = TbankShare & { uid: string };
 
 @Injectable()
@@ -30,7 +32,7 @@ export class StockCatalogService {
   search(userId: string, query: string): Promise<StockSearchResultDto[]> {
     return this.cached(userId, `search:${query}`, async (token) => {
       const found = await this.tbank.findShares(token, query);
-      const shares = selectShares(found, query).slice(0, 30);
+      const shares = selectShares(found, query).slice(0, SEARCH_RESULTS_LIMIT);
       if (!shares.length) return [];
       // One market-data request for the list; failed enrichment must not hide a catalog result.
       const [details, prices] = await Promise.all([
diff --git a/src/modules/investments/instruments/stocks/application/stock-income.service.ts b/src/modules/investments/instruments/stocks/application/stock-income.service.ts
index 8e65d93..a2432f0 100644
--- a/src/modules/investments/instruments/stocks/application/stock-income.service.ts
+++ b/src/modules/investments/instruments/stocks/application/stock-income.service.ts
@@ -20,6 +20,9 @@ import {
 } from '../presentation/stock.dto';
 
 import { StockCatalogService } from './stock-catalog.service';
+
+const ISO_YEAR_LENGTH = 4;
+const INCOME_HISTORY_YEARS = 5;
 @Injectable()
 export class StockIncomeService {
   constructor(
@@ -36,8 +39,8 @@ export class StockIncomeService {
     return this.catalog.cached(userId, `dividends:${uid}`, async (token) => {
       await this.catalog.share(token, uid);
       const today = moscowDay(new Date().toISOString());
-      const from = `${Number(today.slice(0, 4)) - 5}${today.slice(4)}`;
-      const to = `${Number(today.slice(0, 4)) + 1}${today.slice(4)}`;
+      const from = `${Number(today.slice(0, ISO_YEAR_LENGTH)) - INCOME_HISTORY_YEARS}${today.slice(ISO_YEAR_LENGTH)}`;
+      const to = `${Number(today.slice(0, ISO_YEAR_LENGTH)) + 1}${today.slice(ISO_YEAR_LENGTH)}`;
       const unavailable: string[] = [];
       const [events, position] = await Promise.all([
         this.tbank.getDividends(token, uid, from, to),
diff --git a/src/modules/investments/instruments/stocks/application/stock-market.service.ts b/src/modules/investments/instruments/stocks/application/stock-market.service.ts
index 4dc80c9..3ea2464 100644
--- a/src/modules/investments/instruments/stocks/application/stock-market.service.ts
+++ b/src/modules/investments/instruments/stocks/application/stock-market.service.ts
@@ -22,6 +22,12 @@ import {
 const dayMs = 86_400_000;
 
 import { StockCatalogService } from './stock-catalog.service';
+
+const PREVIOUS_CLOSE_LOOKBACK_DAYS = 20;
+const HALF_YEAR_MONTHS = 6;
+const YEAR_MONTHS = 12;
+const CANDLE_WINDOW_DAYS = 365;
+const CHANGE_PERCENT_DECIMAL_PLACES = 6;
 @Injectable()
 export class StockMarketService {
   constructor(
@@ -58,7 +64,9 @@ export class StockMarketService {
                 await this.tbank.getCandles(
                   token,
                   uid,
-                  new Date(end.valueOf() - 20 * dayMs),
+                  new Date(
+                    end.valueOf() - PREVIOUS_CLOSE_LOOKBACK_DAYS * dayMs,
+                  ),
                   end,
                 ),
                 priceAt,
@@ -97,7 +105,7 @@ export class StockMarketService {
                 divide(
                   multiply(difference, decimalFromString('100')),
                   decimalFromString(previousPrice.value),
-                  6,
+                  CHANGE_PERCENT_DECIMAL_PLACES,
                 ),
               )
             : null,
@@ -121,7 +129,11 @@ export class StockMarketService {
         const from = new Date(to);
         from.setUTCMonth(
           from.getUTCMonth() -
-            (period === 'month' ? 1 : period === 'halfYear' ? 6 : 12),
+            (period === 'month'
+              ? 1
+              : period === 'halfYear'
+                ? HALF_YEAR_MONTHS
+                : YEAR_MONTHS),
         );
         if (period === 'all') {
           if (!historyFrom)
@@ -134,7 +146,10 @@ export class StockMarketService {
         const collected = new Map<string, StockCandlesDto['candles'][number]>();
         // Conservative one-year windows also work with older deployed RPC limits.
         for (let start = from.valueOf(); start < to.valueOf();) {
-          const end = Math.min(start + 365 * dayMs, to.valueOf());
+          const end = Math.min(
+            start + CANDLE_WINDOW_DAYS * dayMs,
+            to.valueOf(),
+          );
           for (const candle of await this.tbank.getCandles(
             token,
             uid,
diff --git a/src/modules/investments/instruments/stocks/presentation/stock.dto.ts b/src/modules/investments/instruments/stocks/presentation/stock.dto.ts
index 4683041..405e255 100644
--- a/src/modules/investments/instruments/stocks/presentation/stock.dto.ts
+++ b/src/modules/investments/instruments/stocks/presentation/stock.dto.ts
@@ -11,25 +11,27 @@ import {
 import { MoneyDto } from '../../../../../common/money.dto';
 import { PortfolioPositionDto } from '../../../portfolio/portfolio.api';
 
+const MAX_INSTRUMENT_QUERY_LENGTH = 80;
+
 export class StockSearchQueryDto {
-  @ApiProperty({ minLength: 2, maxLength: 80 })
+  @ApiProperty({ minLength: 2, maxLength: MAX_INSTRUMENT_QUERY_LENGTH })
   @Transform(({ value }: { value: unknown }) =>
     typeof value === 'string' ? value.trim() : value,
   )
   @IsString()
   @MinLength(2)
-  @MaxLength(80)
+  @MaxLength(MAX_INSTRUMENT_QUERY_LENGTH)
   declare query: string;
 }
 export class StockTickerParamsDto {
   @ApiProperty({
     minLength: 1,
-    maxLength: 80,
+    maxLength: MAX_INSTRUMENT_QUERY_LENGTH,
     pattern: '^[A-Za-z0-9][A-Za-z0-9._@+-]*$',
   })
   @IsString()
   @MinLength(1)
-  @MaxLength(80)
+  @MaxLength(MAX_INSTRUMENT_QUERY_LENGTH)
   @Matches(/^[A-Za-z0-9][A-Za-z0-9._@+-]*$/)
   declare ticker: string;
 }
diff --git a/src/modules/investments/investment-calendar.ts b/src/modules/investments/investment-calendar.ts
index e7ff410..051bfbd 100644
--- a/src/modules/investments/investment-calendar.ts
+++ b/src/modules/investments/investment-calendar.ts
@@ -1,3 +1,10 @@
+const MOSCOW_UTC_OFFSET_HOURS = 3;
+const MOSCOW_DAY_END_UTC = {
+  hours: 20,
+  minutes: 59,
+  seconds: 59,
+  milliseconds: 999,
+};
 export type DateOnlyRange = { from: string; to: string };
 const moscow = 'Europe/Moscow';
 export function moscowDate(value: Date): string {
@@ -14,9 +21,21 @@ export function moscowDate(value: Date): string {
 export function dateOnlyBounds(range: DateOnlyRange): { from: Date; to: Date } {
   const from = dateParts(range.from);
   const end = dateParts(range.to);
-  const to = new Date(Date.UTC(end[0], end[1] - 1, end[2], 20, 59, 59, 999));
+  const to = new Date(
+    Date.UTC(
+      end[0],
+      end[1] - 1,
+      end[2],
+      MOSCOW_DAY_END_UTC.hours,
+      MOSCOW_DAY_END_UTC.minutes,
+      MOSCOW_DAY_END_UTC.seconds,
+      MOSCOW_DAY_END_UTC.milliseconds,
+    ),
+  );
   return {
-    from: new Date(Date.UTC(from[0], from[1] - 1, from[2], -3)),
+    from: new Date(
+      Date.UTC(from[0], from[1] - 1, from[2], -MOSCOW_UTC_OFFSET_HOURS),
+    ),
     to: to > new Date() ? new Date() : to,
   };
 }
diff --git a/src/modules/investments/operations/application/brokerage-operations.service.ts b/src/modules/investments/operations/application/brokerage-operations.service.ts
index 73f0ce7..8b4270a 100644
--- a/src/modules/investments/operations/application/brokerage-operations.service.ts
+++ b/src/modules/investments/operations/application/brokerage-operations.service.ts
@@ -1,3 +1,4 @@
+import { MILLISECONDS_PER_SECOND } from '../../../../common/time';
 import {
   BadRequestException,
   Injectable,
@@ -15,6 +16,7 @@ import { AccountReferenceDto } from '../../account-reference.dto';
 import { DateOnlyRange, dateOnlyBounds } from '../../investment-calendar';
 import {
   BrokerageOperationDto,
+  DEFAULT_OPERATIONS_PAGE_SIZE,
   BrokerageOperationsPageDto,
   BrokerageOperationsQueryDto,
 } from '../presentation/brokerage-operation.dto';
@@ -23,6 +25,8 @@ import {
   operationCategory,
 } from '../infrastructure/brokerage-operation.mapper';
 
+const CONTINUATION_TTL_MS = 300_000;
+
 type OperationStream = {
   account: AccountReferenceDto;
   pending: BrokerageOperationDto[];
@@ -54,7 +58,7 @@ export class BrokerageOperationsService {
     AllOperationsContinuation
   >({
     max: 100,
-    ttl: 5 * 60_000,
+    ttl: CONTINUATION_TTL_MS,
     ttlAutopurge: true,
   });
 
@@ -86,7 +90,10 @@ export class BrokerageOperationsService {
           query.instrumentUid && !query.from
             ? {
                 ...range,
-                from: new Date(Number(account.openedDate?.seconds ?? 0) * 1000),
+                from: new Date(
+                  Number(account.openedDate?.seconds ?? 0) *
+                    MILLISECONDS_PER_SECOND,
+                ),
               }
             : range,
         ),
@@ -108,7 +115,7 @@ export class BrokerageOperationsService {
           from: query.from ?? null,
           to: query.to ?? null,
           categories: [...new Set(query.categories ?? [])].sort(),
-          limit: query.limit ?? 100,
+          limit: query.limit ?? DEFAULT_OPERATIONS_PAGE_SIZE,
         });
         const continuation = query.cursor
           ? this.continuations.get(query.cursor)
@@ -178,7 +185,7 @@ export class BrokerageOperationsService {
   ): Promise<BrokerageOperationsPageDto> {
     const items: BrokerageOperationDto[] = [];
     // Each stream retains unconsumed rows. A page boundary never discards them.
-    while (items.length < (query.limit ?? 100)) {
+    while (items.length < (query.limit ?? DEFAULT_OPERATIONS_PAGE_SIZE)) {
       for (const stream of streams) {
         while (!stream.pending.length && !stream.finished) {
           const page = await this.page(
@@ -324,7 +331,9 @@ export class BrokerageOperationsService {
       accountId,
       async ({ token, generation, account }) => {
         const accountOpenedAt = account.openedDate?.seconds
-          ? new Date(Number(account.openedDate.seconds) * 1000)
+          ? new Date(
+              Number(account.openedDate.seconds) * MILLISECONDS_PER_SECOND,
+            )
           : undefined;
         const selected =
           typeof ranges === 'function' ? ranges(accountOpenedAt) : ranges;
@@ -395,7 +404,7 @@ export class BrokerageOperationsService {
       from: seconds(range.from),
       to: seconds(range.to, /^\d{4}-\d{2}-\d{2}$/.test(query.to ?? '')),
       cursor: query.cursor,
-      limit: query.limit ?? 100,
+      limit: query.limit ?? DEFAULT_OPERATIONS_PAGE_SIZE,
       state: 'OPERATION_STATE_EXECUTED',
       ...(query.instrumentUid ? { instrumentId: query.instrumentUid } : {}),
     });
@@ -480,7 +489,7 @@ function cacheKey(
     categories,
     instrumentUid: query.instrumentUid ?? null,
     cursor: query.cursor ?? null,
-    limit: query.limit ?? 100,
+    limit: query.limit ?? DEFAULT_OPERATIONS_PAGE_SIZE,
   });
 }
 
@@ -493,7 +502,7 @@ function dateBoundary(value: string | undefined, end: boolean): Date | null {
 
 function seconds(value: Date, endOfSecond = false) {
   return {
-    seconds: Math.floor(value.valueOf() / 1000).toString(),
+    seconds: Math.floor(value.valueOf() / MILLISECONDS_PER_SECOND).toString(),
     ...(endOfSecond ? { nanos: 999_999_999 } : {}),
   };
 }
diff --git a/src/modules/investments/operations/infrastructure/brokerage-operation.mapper.ts b/src/modules/investments/operations/infrastructure/brokerage-operation.mapper.ts
index d2f9911..35fc796 100644
--- a/src/modules/investments/operations/infrastructure/brokerage-operation.mapper.ts
+++ b/src/modules/investments/operations/infrastructure/brokerage-operation.mapper.ts
@@ -1,3 +1,4 @@
+import { MILLISECONDS_PER_SECOND } from '../../../../common/time';
 import { formatDecimal } from '../../../../common/decimal';
 import {
   TbankMoney,
@@ -84,5 +85,7 @@ function money(value: TbankMoney | undefined) {
 function timestamp(
   value: { seconds?: string | number; nanos?: number } | undefined,
 ) {
-  return new Date(Number(value?.seconds ?? 0) * 1000).toISOString();
+  return new Date(
+    Number(value?.seconds ?? 0) * MILLISECONDS_PER_SECOND,
+  ).toISOString();
 }
diff --git a/src/modules/investments/operations/presentation/brokerage-operation.dto.ts b/src/modules/investments/operations/presentation/brokerage-operation.dto.ts
index 927f68e..c9756a2 100644
--- a/src/modules/investments/operations/presentation/brokerage-operation.dto.ts
+++ b/src/modules/investments/operations/presentation/brokerage-operation.dto.ts
@@ -16,6 +16,10 @@ import { MoneyDto } from '../../../../common/money.dto';
 
 import { AccountReferenceDto } from '../../account-reference.dto';
 
+const MAX_CURSOR_LENGTH = 4096;
+const MAX_OPERATIONS_PAGE_SIZE = 1000;
+export const DEFAULT_OPERATIONS_PAGE_SIZE = 100;
+
 export const operationCategories = [
   'trade',
   'income',
@@ -58,15 +62,19 @@ export class BrokerageOperationsQueryDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsString()
-  @MaxLength(4096)
+  @MaxLength(MAX_CURSOR_LENGTH)
   cursor?: string;
 
-  @ApiPropertyOptional({ minimum: 1, maximum: 1000, default: 100 })
+  @ApiPropertyOptional({
+    minimum: 1,
+    maximum: MAX_OPERATIONS_PAGE_SIZE,
+    default: DEFAULT_OPERATIONS_PAGE_SIZE,
+  })
   @IsOptional()
   @Type(() => Number)
   @IsInt()
   @Min(1)
-  @Max(1000)
+  @Max(MAX_OPERATIONS_PAGE_SIZE)
   limit?: number;
 }
 
diff --git a/src/modules/investments/portfolio/domain/portfolio-structure.ts b/src/modules/investments/portfolio/domain/portfolio-structure.ts
index d60f518..514f167 100644
--- a/src/modules/investments/portfolio/domain/portfolio-structure.ts
+++ b/src/modules/investments/portfolio/domain/portfolio-structure.ts
@@ -6,6 +6,9 @@ import {
 
 import type { Money } from '../../../../common/money.types';
 
+const SHARE_PERCENT_DECIMAL_PLACES = 6;
+const PERCENT_SCALED_FACTOR = 100_000_000n;
+
 const categoryTypes = ['STOCK', 'BOND', 'OTHER', 'CASH'] as const;
 
 // Build from positions and cash, never from totals (which already include cash).
@@ -59,10 +62,10 @@ export function portfolioStructure(
                 value:
                   (value.value *
                     10n ** BigInt(total.scale - value.scale) *
-                    100_000_000n +
+                    PERCENT_SCALED_FACTOR +
                     total.value / 2n) /
                   total.value,
-                scale: 6,
+                scale: SHARE_PERCENT_DECIMAL_PLACES,
               })
             : null,
         }));
diff --git a/src/modules/investments/tbank-connection/tbank-connection.controller.ts b/src/modules/investments/tbank-connection/tbank-connection.controller.ts
index 9247d1a..4e7943b 100644
--- a/src/modules/investments/tbank-connection/tbank-connection.controller.ts
+++ b/src/modules/investments/tbank-connection/tbank-connection.controller.ts
@@ -4,6 +4,7 @@ import {
   Delete,
   Get,
   HttpCode,
+  HttpStatus,
   Put,
   Req,
   UseGuards,
@@ -47,7 +48,7 @@ export class TbankConnectionController {
   }
 
   @Delete()
-  @HttpCode(204)
+  @HttpCode(HttpStatus.NO_CONTENT)
   @ApiNoContentResponse()
   delete(@Req() request: Request & { user: AccessPayload }): Promise<void> {
     return this.connection.delete(request.user.sub);
diff --git a/src/modules/investments/tbank-connection/tbank-connection.dto.ts b/src/modules/investments/tbank-connection/tbank-connection.dto.ts
index 32a8aae..fd0dcb8 100644
--- a/src/modules/investments/tbank-connection/tbank-connection.dto.ts
+++ b/src/modules/investments/tbank-connection/tbank-connection.dto.ts
@@ -1,11 +1,13 @@
 import { ApiProperty } from '@nestjs/swagger';
 import { IsNotEmpty, IsString, MaxLength } from 'class-validator';
 
+const MAX_TOKEN_LENGTH = 4096;
+
 export class PutTbankConnectionDto {
   @ApiProperty({ writeOnly: true })
   @IsString()
   @IsNotEmpty()
-  @MaxLength(4096)
+  @MaxLength(MAX_TOKEN_LENGTH)
   declare token: string;
 }
 
diff --git a/src/modules/investments/upcoming-events/upcoming-events.service.ts b/src/modules/investments/upcoming-events/upcoming-events.service.ts
index 530d3e8..d169990 100644
--- a/src/modules/investments/upcoming-events/upcoming-events.service.ts
+++ b/src/modules/investments/upcoming-events/upcoming-events.service.ts
@@ -1,3 +1,4 @@
+import { MILLISECONDS_PER_SECOND } from '../../../common/time';
 import { BadRequestException, Injectable } from '@nestjs/common';
 import {
   add,
@@ -25,12 +26,14 @@ import {
   UpcomingEventsQueryDto,
 } from './upcoming-events.dto';
 
+const DEFAULT_EVENT_WINDOW_DAYS = 30;
+
 type Position = NonNullable<TbankPortfolio['positions']>[number];
 type CachedEntry<T> = { expiresAt: number; promise: Promise<T> };
 
 const positionsBatchSize = 5;
-const dividendCacheTtlMs = 15 * 60_000;
-const instrumentCacheTtlMs = 24 * 60 * 60_000;
+const dividendCacheTtlMs = 900_000;
+const instrumentCacheTtlMs = 86_400_000;
 
 @Injectable()
 export class UpcomingEventsService {
@@ -242,7 +245,9 @@ export class UpcomingEventsService {
     return {
       ...metadata,
       type: 'dividend',
-      date: new Date(Number(event.recordDate?.seconds) * 1000)
+      date: new Date(
+        Number(event.recordDate?.seconds) * MILLISECONDS_PER_SECOND,
+      )
         .toISOString()
         .slice(0, 10),
       dateKind: 'registry',
@@ -287,7 +292,7 @@ function supported(position: Position): boolean {
 function dateWindow(query: UpcomingEventsQueryDto) {
   const from = query.from ?? new Date().toISOString().slice(0, 10);
   const end = new Date(`${from}T00:00:00.000Z`);
-  end.setUTCDate(end.getUTCDate() + 30);
+  end.setUTCDate(end.getUTCDate() + DEFAULT_EVENT_WINDOW_DAYS);
   const to = query.to ?? end.toISOString().slice(0, 10);
   if (from > to)
     throw new BadRequestException({ code: 'INVALID_EVENTS_PERIOD' });