I'm building an API platform and need routing, auth, and rate limiting

Here’s a solid, practical way to think about building an API platform with routing, auth, and rate limiting.

1) Routing

What you need

• Path routing: /v1/users, /v1/orders/:id
• Method routing: GET, POST, PUT, DELETE
• Versioning: /v1/... or header-based versioning
• Middleware chain: auth, logging, rate limiting, validation

Recommended structure

• API Gateway / Edge Router
  • Handles public entry point
  • Terminates TLS
  • Applies coarse rate limits
  • Authenticates requests
  • Routes to internal services
• Service-level router
  • Handles business endpoints
  • Applies resource-specific checks

Best practices

• Use consistent resource naming:
  • /users
  • /users/{userId}
  • /users/{userId}/sessions
• Keep verbs out of paths unless it’s an action:
  • Prefer POST /payments
  • Avoid /createPayment
• Centralize route registration to avoid drift

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2) Authentication

Common options

API Keys

• Simple and good for machine-to-machine integrations
• Usually sent via header:
  • X-API-Key: ...
• Pros: easy to implement
• Cons: weak if leaked; no user identity granularity unless paired with scopes

OAuth 2.0 / OpenID Connect

• Best for third-party access and user-based authorization
• Use:
  • Authorization Code flow for user login
  • Client Credentials flow for service-to-service
• Supports scopes and token expiration

JWT

• Useful as an access token format
• Self-contained, stateless verification
• Use short-lived access tokens plus refresh tokens
• Validate:
  • signature
  • issuer
  • audience
  • expiry
  • scope/roles

Auth design suggestions

• For public APIs: API keys + HMAC signing or OAuth2
• For internal service-to-service: mTLS or OAuth2 client credentials
• For user-facing APIs: OIDC + JWT access tokens

Authorization vs authentication

• Authentication: who are you?
• Authorization: what can you do?
• Don’t mix them.

Security practices

• Store secrets hashed where possible
• Rotate keys regularly
• Support key revocation
• Log auth failures without leaking secrets
• Use HTTPS everywhere

---

3) Rate limiting

Why it matters

• Prevent abuse
• Protect backend systems
• Enforce plan tiers
• Ensure fair usage

Common algorithms

Token bucket

• Best general-purpose choice
• Allows bursts while enforcing long-term rate
• Example:
  • 100 tokens/minute
  • burst up to 20
• Good for APIs where short bursts are acceptable

Leaky bucket

• Smooths traffic
• More rigid than token bucket

Fixed window

• Easy to implement
• Can allow burst at window boundaries
• Less precise

Sliding window

• More accurate than fixed window
• More expensive to implement

What to rate limit by

• API key
• User ID
• IP address
• Endpoint
• Tenant/org
• Combination of the above

Recommended policy layering

1. Global edge limit per IP/API key
2. Per-tenant limit
3. Per-endpoint limit
4. Sensitive endpoint stricter limits
   • login
   • password reset
   • OTP verification

Responses

• Return 429 Too Many Requests
• Include:
  • Retry-After
  • rate limit headers if useful:
    • X-RateLimit-Limit
    • X-RateLimit-Remaining
    • X-RateLimit-Reset

Implementation note

• Use a shared store like:
  • Redis
  • Memcached
  • distributed rate-limit service
• Avoid in-memory limits if you run multiple instances unless you only need best-effort local limits

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4) Suggested request flow

A strong default flow:

1. Request hits gateway
2. TLS terminated
3. Basic request validation
4. Rate limit check
5. Authenticate request
6. Authorize scope/role
7. Route to backend service
8. Service handles business logic
9. Return response with audit/logging

---

5) Example architecture

• Client
• API Gateway
  • TLS
  • routing
  • rate limiting
  • auth validation
• Auth service / IdP
  • issues tokens
  • manages users/clients
• Microservices
  • users
  • billing
  • orders
• Redis
  • rate limiting counters
  • sessions / token revocation lists if needed
• Observability
  • logs
  • metrics
  • tracing

---

6) Practical recommendation by platform type

If you’re early-stage

Use:

• API Gateway or reverse proxy like Nginx, Envoy, Kong, or Traefik
• JWT auth
• Redis-backed token bucket rate limiting

If you need developer-friendly public APIs

Use:

• API keys for app identification
• OAuth2 for user auth
• Per-plan quotas
• Good dashboards and key rotation

If you need enterprise-grade controls

Use:

• OIDC/OAuth2
• mTLS for internal traffic
• fine-grained scopes
• tenant-aware rate limiting
• audit logs

---

7) Minimal endpoint policy example

• GET /v1/items
  • auth required
  • read scope
  • 300 req/min per API key
• POST /v1/items
  • auth required
  • write scope
  • 60 req/min per API key
• POST /v1/auth/login
  • no token required
  • 10 req/min per IP
• POST /v1/auth/otp/verify
  • 5 req/min per user + IP

---

8) My recommendation

If you want a sane default stack:

• Routing: API Gateway with versioned REST routes
• Auth: OAuth2/OIDC + JWT access tokens
• Rate limiting: Redis-backed token bucket
• Authorization: scopes/roles/tenant checks
• Observability: structured logs + request IDs + tracing

If you want, I can also give you:

1. a reference architecture diagram,
2. a database schema for API keys/tokens/quotas, or
3. implementation examples in Node.js, Go, Python, or Rust.