Web App Manifest Validator

How to use this developer tool

1. Paste the manifest json or load the sample.
2. Adjust any options shown below the editor.
3. Select Validate Manifest or press Ctrl/Cmd + Enter.
4. Review diagnostics before copying or downloading the result.

What this developer tool does

The result panel shows the processed manifest json, a concise status, and measurements that describe this specific run.

Warnings identify conditions worth reviewing; they do not replace testing in the browser or service that consumes the output.

Example

The included sample demonstrates a representative input. Running it produces the exact format shown in the output panel, including any relevant diagnostics.

{"name":"Example Tasks","short_name":"Tasks","start_url":"/app/","scope":"/app/","display":"standalone","theme_color":"#7c3aed","background_color":"#ffffff","icons":[{"src":"/icons/icon-192.png","sizes":"192x192","type":"image/png"},{"src":"/icons/icon-512.png","sizes":"512x512","type":"image/png"}]}

Use cases

• Prepare metadata or server-facing files before a release.
• Audit a copied head fragment during an SEO review.
• Turn structured notes into consistent deployment markup.

Tips for reliable output

• Use absolute URLs where a crawler must resolve the resource.
• Keep values aligned with the final production origin.
• Act on warnings before copying the result.
• Test generated output in a staging page.
• Re-run the tool after changing filenames or routes.

Processing details

All parsing and generation happens in the current browser tab. Values are normalized only where the relevant format permits it, and the original input is never uploaded.

Live fetch results, crawler caches, HTTP response headers, and platform-specific acceptance checks are outside this page’s browser-only scope.