🔧 Tech Debt & Code Quality

API v1 endpoints deprecated 18 months ago but still serving 12% of traffic. Old mobile apps (v1.x) still hitting these endpoints. Plan: 1) Identify all v1 users (analytics) 2) Force update for apps older than v2.0 (released 12 months ago) 3) Show deprecation warning in-app (30 days) 4) Redirect v1 to v2 endpoints with transformation layer (60 days) 5) Remove v1 completely (90 days). Issues: breaking changes in v2, some users never update apps. Alternatives: maintain v1 forever (cost), sunset old apps (user loss). Communication plan: email notifications, in-app banners, App Store update prompts. Document migration guide for API consumers. Est: 8 story points. Reduces maintenance burden.

Remove deprecated API endpoints still used by old mobile app versions

`npm audit` shows 47 vulnerabilities (23 high, 8 critical). Dependencies outdated: React 17, Express 4.16, lodash 4.17.15. Known CVEs: prototype pollution, regex DoS, XSS vulnerabilities. Update plan: 1) Update patch versions (low risk) 2) Update minor versions with testing 3) Major version updates (may require code changes) 4) Remove unused dependencies. Test thoroughly: regression tests, security scans, performance testing. Problem deps: node-sass (deprecated, switch to dart-sass), request (deprecated, switch to axios). Setup Dependabot for automated PR updates. Document: breaking changes, migration notes. Priority: P1 - security risk. Est: 8 story points.

Update outdated dependencies with security vulnerabilities

Codebase has 200+ console.log statements, no structured logging, can't filter or search logs effectively. Production logs full of debug messages. Implement proper logging: 1) Winston or Pino for backend 2) LogRocket or custom for frontend 3) Log levels (error, warn, info, debug) 4) Structured logging (JSON format) 5) Context (user ID, request ID, timestamp). Features: log rotation, log shipping to ELK, PII redaction, performance impact minimal. Remove all console.log, replace with logger.debug(). Configure: production = error/warn only, staging = info, dev = debug. Add logging guidelines to docs. Quick win, 5 story points.

Replace console.log debugging with proper logging framework

Several classes violating single responsibility principle: UserService (3200 lines), OrderController (2800 lines), DataProcessor (4500 lines). Unmaintainable, hard to test, merge conflicts common. Refactor plan: 1) Identify separate responsibilities 2) Extract into focused classes 3) Dependency injection for testability 4) Update tests. Example: UserService → UserAuth, UserProfile, UserSettings, UserNotifications. Benefits: easier testing, better code organization, reduced merge conflicts, clearer responsibilities. Challenges: breaking internal APIs, updating all imports, maintaining backward compatibility. Use SOLID principles. Incremental refactor with feature flags. Est: 13 story points. High value for maintainability.

Refactor god classes with 3000+ lines into smaller modules

Code analysis shows 35% code duplication. Same logic repeated in multiple components: form validation (12 places), API error handling (20 places), date formatting (30 places), permission checks (15 places). Create shared utilities: 1) Common hooks (useForm, useApi, usePagination) 2) Utility functions (formatters, validators) 3) Shared components (ErrorBoundary, LoadingSpinner) 4) Constants file (API URLs, config). Use: extract common patterns, DRY principle, composition over duplication. Benefits: consistency, easier updates, reduced bundle size, fewer bugs. Tools: jscpd for duplicate detection. Est: 13 story points. Improves maintainability.

Eliminate duplicate code across frontend components (DRY violations)

Error handling all over the place: try-catch in some places, callbacks in others, errors thrown vs returned, inconsistent error objects. No standard error handling pattern. Create: 1) Centralized error handling middleware 2) Custom error classes (ValidationError, AuthError, NotFoundError) 3) Standard error response format 4) Error codes for client handling 5) Error logging to Sentry. Patterns: async/await with try-catch, never swallow errors, always propagate with context. Frontend: global error handler, axios interceptors, React error boundaries. Backend: Express error middleware. Document: error handling guidelines. Est: 8 story points. Improves reliability.

Fix inconsistent error handling patterns across codebase

Legacy code using callbacks causing pyramid of doom, hard to read and maintain. Example: 8 nested callbacks in payment processing, error handling nightmare. Convert to async/await: cleaner, easier error handling with try-catch, better debugging. Files to update: legacy API routes (30 files), database operations (20 files), file operations (10 files). Challenges: converting callback-based libraries (promisify), handling parallel operations (Promise.all), error propagation. Use: util.promisify for Node callbacks. Benefits: readable code, easier debugging, modern JavaScript. Est: 8 story points. Developer experience improvement.

Migrate callback hell to async/await for better readability

Inconsistent code style across team: tabs vs spaces, semicolons vs none, single vs double quotes, inconsistent indentation. Code reviews waste time on style discussions. Setup: 1) Prettier for auto-formatting 2) ESLint for code quality rules 3) Pre-commit hooks (Husky) 4) CI checks for formatting 5) VS Code settings for team. Rules: 2 spaces, single quotes, trailing commas, semicolons. Format entire codebase (one big commit). Also: EditorConfig file, .prettierrc shared config. Benefits: consistent code, no style debates, auto-fix on save. Team training: using formatters. 3 story points. Quick win.

Standardize code formatting with Prettier and ESLint

Code full of magic values: if (status === 'active'), timeout = 5000, maxRetries = 3, port 8080. Unclear what numbers mean, hard to change values. Extract to constants: 1) Create constants file per module 2) Named exports with SCREAMING_SNAKE_CASE 3) Add JSDoc comments explaining purpose 4) Group related constants. Examples: USER_STATUS_ACTIVE, API_TIMEOUT_MS, MAX_RETRY_ATTEMPTS, DEFAULT_PORT. Benefits: self-documenting code, single source of truth, easier to change. Review: all hardcoded numbers/strings except obvious ones (0, 1, empty string). Est: 5 story points. Code quality improvement.

Replace magic numbers and strings with named constants

Internal APIs have zero documentation. New developers can't understand services, lots of 'how does this work?' questions, tribal knowledge problem. Create documentation: 1) OpenAPI/Swagger for REST APIs 2) GraphQL schema docs 3) Service architecture diagrams 4) Integration guides 5) Example requests/responses. Include: authentication, error codes, rate limits, versioning. Use: Swagger UI for interactive docs, host on internal wiki. Also document: database schema, event system, message queues, cron jobs. Benefits: faster onboarding, reduced interruptions, knowledge preservation. Est: 8 story points. Investment in team productivity.

Document undocumented internal APIs and services

Database changes via manual SQL scripts, no version control, no rollback mechanism, production schema drift from dev/staging. Implement proper migrations: 1) Migration framework (Sequelize, TypeORM, or Knex) 2) Version controlled migrations 3) Up/down migrations for rollback 4) Automatic execution in deployment 5) Migration status tracking. Features: schema versioning, data migrations, safe rollbacks, consistent environments. Workflow: create migration, test locally, review in PR, auto-apply in deployment. Backfill: document current schema, create initial migration. Est: 8 story points. Reduces deployment risk.

Implement database migrations instead of manual SQL scripts

Feature flag system cluttered with 45 old flags for features fully released. Dead code paths, confusion for new developers, A/B test flags still in code. Cleanup: 1) Identify flags for features fully rolled out (>6 months) 2) Remove flag checks from code 3) Keep winning variant for A/B tests 4) Update feature flag service 5) Document which flags removed. Flags to remove: newDashboard (shipped 8 months ago), betaSearch (GA 10 months ago), experimentalUI (sunset 1 year ago). Use: git grep to find all usages. Test thoroughly: might still be referenced. Benefits: cleaner code, faster execution, reduced complexity. 5 story points.

Remove feature flags for features shipped 6+ months ago

Current test coverage: 45% (backend), 30% (frontend). Critical paths untested, recent bugs would've been caught by tests. Goal: 80% coverage. Focus: 1) Critical business logic (payments, auth, data processing) 2) Regression-prone areas 3) Edge cases and error conditions 4) Integration tests for key flows. Use: Jest, React Testing Library, Supertest for API. Strategy: test when fixing bugs (regression tests), test before refactoring, test new features. Add: coverage gates in CI (fail if drops), coverage reports in PR. Not chasing 100% - diminishing returns. Est: 21 story points. Ongoing effort.

Improve test coverage from 45% to 80%+

Slow query log shows 15 queries taking 2-10 seconds. Examples: dashboard aggregation (8s), user search (5s), report generation (12s). Analysis: 1) Missing indexes on foreign keys 2) Full table scans 3) N+1 queries 4) Inefficient joins 5) No query result caching. Optimizations: add indexes (immediate win), rewrite queries with proper joins, implement caching, paginate large results, use database views for complex queries. Use EXPLAIN ANALYZE to understand query plans. Monitor: query performance before/after. Create: database performance guidelines. Target: all queries <500ms. Est: 8 story points. High impact on performance.

Optimize slow SQL queries identified in performance profiling

Global CSS file 5000+ lines, specificity wars, !important everywhere, unclear what styles used where. Can't safely remove CSS - fear of breaking something. Migrate to component-scoped CSS: 1) CSS Modules or styled-components 2) One stylesheet per component 3) Use CSS variables for theming 4) Remove global styles gradually. Benefits: style isolation, no class name conflicts, co-located with components, safe to delete. Challenges: visual regressions, time-consuming. Use: visual regression testing, start with isolated components. Also: remove unused CSS (PurgeCSS). Est: 13 story points. Improves maintainability.

Inbox

🔧 Tech Debt & Code Quality

Identified

Prioritized

In Progress

Review

Done