Datamuse vs Metabase

Datamuse is a free word-finding query engine for autocomplete, rhyme, and meaning-based lookups; a live unauthenticated GET against `api.datamuse.com/words` returned a 200 JSON array with `Access-Control-Allow-Origin` echoing the request Origin plus `Access-Control-Allow-Credentials: true`, resolving cors "unknown" to "yes". Its own homepage now states that starting January 1, 2027 an API key will be required on every request (capped at 100,000/day per key) after more than a decade of fully free access — as of this check the API still works with no key at all.

Metabase is a self-hosted (or Metabase Cloud) open-source BI tool whose REST API is documented via an interactive OpenAPI/Scalar reference at `/docs/latest/api`; current docs describe generating an `x-api-key` from Admin settings for programmatic access, correcting auth from "None" to "API Key" (the older session-cookie login flow still exists but keyed API access is now the documented path). Its own `MB_DISABLE_CORS_ON_LOCALHOST` config option (default `false`) confirms the server sends CORS headers by default, consistent with cors "yes". The core server is free and open-source to self-host, with paid Pro, Enterprise, and hosted Cloud tiers layered on top.