VoriTools

Inspect a web app manifest’s declared settings

Paste manifest.webmanifest content to inspect its settings. The tool does not fetch icons, check a service worker or certify that a browser will offer installation.

Runs locally in your browser
View category: Frontend & Design (34)
This tool processes all data locally in your browser.
Web App Manifest JSONPaste manifest.webmanifest content. The checker reads it locally and never requests its assets.

How to inspect a web app manifest

Paste the JSON of a manifest.webmanifest file and the page reports what a browser would read from it: the name, the start URL, the display mode, the declared icons and the theme colours, plus the normalized JSON you can copy back into your project.

Everything runs in this browser. The page never fetches the manifest URL, the icons or the site behind it, so a passing result means the declared fields are sound — not that the install prompt will appear.

  1. Paste the manifest JSON into Web App Manifest JSON, or press Load example for a complete sample.
  2. Press Inspect manifest. The parser message is shown when the text is not valid JSON, so a trailing comma or a stray character is easy to find.
  3. Read Manifest fields: name, start_url, display, icon count and theme colour, each exactly as the manifest declares them.
  4. Read the findings list: red rows make the manifest invalid for browsers, yellow rows are worth fixing, grey rows are review notes such as a missing purpose.
  5. Copy or Download the normalized JSON (2-space indentation, saved as manifest.webmanifest); Clear empties both panes.

What this page reads, and what it leaves to you

Fields the checker validates

name and short_name must be strings, and at least one of them has to be present. start_url must be a string and must parse as a URL; a non-string value is reported because browsers ignore it and fall back to the document URL.

display must be a string and one of fullscreen, standalone, minimal-ui or browser. icons must be an array; every entry needs a src, sizes must be "any" or a width x height list, and purpose accepts only any, maskable and monochrome. theme_color and background_color are checked with the browser’s own CSS colour parser.

How the result is graded

The banner follows the worst finding: green only when the findings list is empty, yellow when there are warnings, red for errors such as invalid JSON, a non-object root, a non-string start_url, icons that are not an array or an icon without src.

Findings name the field or the icon index, and the value that caused them, so the manifest can be fixed without guessing.

What this page does not do

It does not request the manifest, the icons or any other asset, does not look at a service worker and does not test installation. relative start_url values are checked for syntax only; nothing is resolved against your real manifest URL.

A UTF-8 byte order mark at the start of the pasted text is tolerated, because editors add them; anything else that is not plain JSON is reported with the parser message.

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