GitHub ReadMe Stats vs Shields

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.

Shields.io serves status badges as SVG by default from `img.shields.io`, with `.png` requests 301-redirected to a raster-conversion host and a `.json` suffix returning the same badge's label/value/color as plain JSON — all three confirmed live. A live unauthenticated GET returned `Access-Control-Allow-Origin: *` on every format, resolving cors "unknown" to "yes". Free, open-source, and keyless, funded by sponsorships rather than a paid tier.