Rate limits and cache

Rate limit

120 requests / 60 seconds / key (kid). Over the limit:

{ "error": { "code": "rate_limited", "message": "…" } }

Status 429. MCP calls count against the same budget (they hit the API over a service binding).

/health and /openapi.json are not rate-limited.

Point-lookup cache

These GETs are cached at the Worker after auth. The cache key is the URL only (24h).

• GET /v1/isbn/:isbn
• GET /v1/books/:id
• GET /v1/works/:id
• GET /v1/authors/:id

Response header: X-Cache: HIT or MISS.

Hot ISBN lookups should land well under 200ms on a hit. Misses pay Hyperdrive + join.

Search, match, recommend, author search, and changes are short-TTL and hit Postgres.

Metering

Authenticated /v1 calls are written to usage_events asynchronously. Do not expect a usage field on the response.

See also

• Errors
• Known gaps