Middleware & Policies

Rate Limiting

Rate limits are enforced per-tenant using a Redis sliding window counter.

Scope	Window	Limit
Authenticated requests	60 seconds	300 per tenant
Unauthenticated requests	60 seconds	30 per IP

Rate limit headers are included on every authenticated response:

X-RateLimit-Limit: 300
X-RateLimit-Remaining: 285
X-RateLimit-Reset: 1738900860

When the limit is exceeded, the API returns 429 Too Many Requests with a Retry-After header indicating seconds until the next window.

Request Tracing

Every request receives a unique request ID for distributed tracing:

• If the client sends an X-Request-Id header, the server uses that value
• Otherwise, the server generates req_{ULID} (e.g., req_01ARZ3NDEKTSV4RRFFQ69G5FAV)
• The request ID appears in the response X-Request-Id header and in the instance field of all error responses

Idempotency

POST endpoints that create resources accept an optional Idempotency-Key header (UUID). Duplicate requests with the same key return the stored response without re-executing. Keys are stored for 24 hours.

PUT, DELETE, and GET are naturally idempotent.

CORS

Setting	Value
Allowed origins	Configurable via AKILI_CORS_ORIGINS env var
Allowed methods	GET, POST, PUT, PATCH, DELETE, OPTIONS
Allowed headers	Authorization, Content-Type, X-Request-Id, X-Tenant-Id
Exposed headers	X-Request-Id, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset
Max age	3600 seconds
Credentials	true