Summary Core Architecture & Backend Setup
1. Design system architecture using microservices in Go (auth, wallet, engine, user, etc.)
2. Set up PostgreSQL database (schemas for users, orders, balances, KYC)
3. Configure Redis for rate limiting, caching, and queues
4. Implement JWT-based authentication and refresh tokens
5. Build role-based access control (RBAC) for admin/user/support roles
6. Develop secure OAuth2 flows using Go (password grant, token issuance)
7. Build user registration/login, password reset, session handling
8. Add Google Authenticator (TOTP) for 2FA login security
9. Implement audit logging for logins, actions, KYC changes, withdrawals

  Wallets & Crypto Functionality
10. Integrate native wallet support for ETH, BTC, BSC, Polygon (or use APIs like BlockCypher, Tatum)
11. Create hot wallet management service (sending, receiving, monitoring)
12. Create cold wallet withdrawal process with admin override (optional)
13. Build automated deposit address generation per user
14. Implement transaction monitoring to detect incoming deposits
15. Queue and process outgoing withdrawals with security checks
16. Calculate and apply deposit/withdrawal fees
17. Store wallet secrets securely using HashiCorp Vault or envvars

Trading & Exchange Logic
18. Build a lightweight trading engine (limit & market orders, FIFO match)
19. Create APIs for placing/canceling orders
20. Track user balances and reserved funds per open order
21. Maintain live order books (optional: in-memory or persisted)
22. Store executed trades and user trading history
23. Expose market data via REST (order book, ticker, volume)
24. Optional: Set up real-time WebSocket feed for market events

KYC & Compliance
25. Integrate KYC provider (Sumsub or similar) via REST API
26. Handle applicant creation, document upload, and status polling
27. Enforce withdrawal limits based on KYC tier (configurable)
28. Log KYC status and verification metadata per user
29. Block risky or flagged accounts based on KYC response
30. Optional: add IP geofencing, device fingerprinting hooks

Security Hardening
31. Apply TLS (HTTPS) to all services via NGINX or Caddy
32. Add HTTP security headers: CSP, HSTS, X-Frame-Options
33. Enable CSRF protection (for frontend forms)
34. Prevent XSS in API responses
35. Set API rate limits per endpoint/IP/user (via Redis or middleware)
36. Secure JWT tokens (expiry, revocation, blacklist if needed)
37. Store all secrets in a secure store (Vault or Kubernetes secrets)

  DevOps & Launch Readiness
38. Dockerize all backend services with Docker Compose
39. Write deployment scripts (bash or Terraform)
40. Configure PostgreSQL backups and recovery policy
41. Set up logging (e.g., Logrus or Zap) and rotating logs
42. Write simple CI/CD pipeline (GitHub Actions or GitLab CI)
43. Provide basic API documentation (Swagger or Postman collection)
44. Write admin CLI or API for user/block/withdraw/approve
45. Prepare for penetration testing using OWASP checklist
46. Optional: set up Prometheus/Grafana or UptimeRobot for health checks