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web validator

Web App Manifest Validator

Validate web app manifests (manifest.json) client-side: names, start_url, display, and icons.

Results

Processing…
Status
Processing...
Details
Processing...
Icons
Processing...
start_url
Processing...
display
Processing...

How to use this validator

  1. Paste the manifest.json content.
  2. Run validate to check required fields, display, and icon entries.
  3. If invalid, add missing fields or sizes, then re-run.

Rules & checks

Requires name or short_name.

Requires start_url.

display must be one of fullscreen, standalone, minimal-ui, or browser.

icons should include src and sizes; counts icons present.

Inputs explained

  • Manifest JSON

    Paste manifest.json content. Include name/short_name, start_url, display, and icons with src/sizes.

When to use it

  • QA PWA manifests before deployment
  • Validate CMS-generated manifest.json outputs
  • Check icons metadata before packaging for stores

Common errors

  • Missing name/short_name
  • Missing start_url
  • Invalid display value
  • Icons without sizes/src

Limitations

  • Structure validation only; does not fetch or render icons or verify service worker setup.
  • Does not validate related_applications or shortcuts deeply.

Tips

  • Provide multiple icon sizes (e.g., 192x192, 512x512) with type=image/png
  • Use absolute or root-relative paths for start_url and icons
  • Keep name and short_name concise for install surfaces

Examples

Valid manifest

  • { "name": "App", "start_url": "/", "display": "standalone", "icons": [{ "src": "/icon-192.png", "sizes": "192x192" }] }

Missing icon sizes

  • icons without sizes -> flagged

Invalid display

  • display: "foo" -> flagged

Deep dive

This web app manifest validator checks required fields, display mode, and icon entries entirely in your browser.

Use it to validate manifest.json from CMS/static builds before launch without uploading files.

FAQs

Is anything uploaded?
No. Validation runs in-browser and clears on refresh.
Do you fetch icons?
No. This checks manifest structure only; it does not fetch assets.

Related validators

web

URL Validator

Validate HTTP/HTTPS URLs locally—parse host/path and catch malformed links before publishing or sending to APIs.

All validation happens in your browser. No data is sent, logged, or stored.

Structure validation only; does not fetch or render icons or verify service worker setup.