Datamuse vs GitHub ReadMe Stats

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.

GitHub Readme Stats generates SVG stat/language/pin cards for GitHub profile READMEs; its handler explicitly sets `Content-Type: image/svg+xml` and, per its own README, the shared public demo at `github-readme-stats.vercel.app/api` is "best-effort and can be unreliable due to rate limits and traffic spikes" (confirmed today: it returned a `DEPLOYMENT_PAUSED` 503) — the project itself is very much alive (58k+ GitHub stars, commits within the last week) and explicitly recommends self-hosting or a GitHub Actions workflow instead of relying on the shared instance. Neither the Vercel serverless handlers nor Vercel's platform add a CORS header by default, correcting cors from "yes" to "no". Free and open-source, self-hostable.