GitHub Contribution Chart Generator vs Shields

This is a keyless JSON API (not an image-rendering service, despite the name) with a single route, `/api/v1/{username}`, that returns a GitHub user's daily/yearly contribution counts — confirmed by inspecting the project's own source tree, which contains only one API file (`src/pages/api/v1/[username].js`); the actual chart image is drawn client-side from that JSON by a separate canvas library. A live unauthenticated GET returned a 200 JSON payload with no `Access-Control-Allow-Origin` header at all, correcting cors from "yes" to "no" (the header only appears on Vercel's default 404 page, not on the real route). Free and open-source, self-hostable on Vercel.

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.