Hi everyone, this is Web App Manifest Checker API. Give it a page URL and it finds the site's Web App Manifest, fetches it and validates it against the W3C Web App Manifest spec, returning JSON: coded issues, an overall grade (A+ to F), a score out of 100 and an installability verdict with the blockers that stop Chrome from offering install. The installability verdict follows Chrome's manifest-level install criteria only (name or short_name, same-origin start_url inside scope, installable display mode, a 192px icon, no prefer_related_applications, HTTPS). Everything else (512px and maskable icons, colors, lang, shortcuts, screenshots) is quality advice. The grade and score use our own weighting; this is not a Lighthouse score and does not guarantee that a browser will show an install prompt. Two endpoints: - GET /v1/check?url= reads the page (up to 5 redirects, first 512 KB of HTML), follows its manifest link and checks the manifest. Cached for 6 hours per URL; fresh=1 bypasses the cache. - POST /v1/validate checks manifest JSON you paste in, offline, with no outbound request. Limits: service workers, offline support and whether icon files actually load are not checked. Manifest tags injected by JavaScript and manifests declared only in an HTTP Link header are not detected. Sites that block datacenter traffic return grade unchecked. Private-network targets are rejected. Examples measured on 2026-10-13: web.dev scored B (86) and installable; starbucks.com was reported not installable because display is missing. Where to find it: RapidAPI (public, https://rapidapi.com/tossneon0/a...), API.Market and APIHub; Zyla is in review. Product site: https://web-manifest.glowhalo.org Feedback on the checks and the scoring is welcome.

Web App Manifest Checker API

PWA manifest and installability report as JSON

PWA manifest and installability report as JSON