SaaS Starter Architecture

Production-ready SaaS backend with authentication, user management, billing, and transactional email.

Services

• API Gateway (api_gateway) — Routes and rate-limits API requests — Express, Node.js
• Auth Service (service) — Handles authentication and token management — Node.js, Passport
• AWS Cognito (external) — Manages user identity pools — AWS Cognito
• User Service (service) — Manages user profiles and preferences — Node.js, TypeScript
• Billing Service (service) — Manages subscriptions and invoicing — Node.js, TypeScript
• Stripe (external) — Processes subscription payments — Stripe API
• Email Service (service) — Sends transactional and marketing emails — Python, SendGrid
• PostgreSQL (database) — Stores users, subscriptions, and app data — PostgreSQL
• Redis (database) — Caches sessions and rate-limit counters — Redis

Connections

• API Gateway → Auth Service (sync_http)
• API Gateway → User Service (sync_http)
• API Gateway → Billing Service (sync_http)
• Auth Service → AWS Cognito (sync_http)
• Billing Service → Stripe (sync_http)
• Billing Service → Email Service (async_event)
• Auth Service → Redis (db_access)
• User Service → PostgreSQL (db_access)
• Billing Service → PostgreSQL (db_access)