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Web App Manifest Validator

Validate your manifest.json against the W3C Web App Manifest spec and the Chrome and Edge install criteria. Find errors, warnings, and PWA install blockers.

Paste your manifest.json826 chars

Paste the contents of your manifest.json or .webmanifest file. The validator runs every check locally in your browser. Nothing is uploaded.

Summary

Errors
0
Warnings
0
Notes
1
Installable
Yes

Install criteria

The first five rows must pass for Chrome and Edge to show the browser install prompt. A maskable icon is recommended for adaptive Android home screens.

Has a name or short_name
Browsers will use this as the home screen label.
Has a start_url
Browsers will navigate to this URL when the app launches.
display is standalone, fullscreen, or minimal-ui
Display mode qualifies for the browser install prompt.
Has a 192x192 icon with purpose any (or larger)
Home screen icon is covered.
Has a 512x512 icon with purpose any (or larger)
Splash and install dialog icon is covered.
Has a maskable icon (recommended)
Adaptive Android home screen tiles will render cleanly.

Notes (1)

screenshots
screenshots is missing. Recommended; Chrome shows a richer install dialog when screenshots are declared.

Normalized manifest

Keys reordered into the conventional PWA documentation order. Unknown and deprecated keys are appended at the end so they remain visible until you remove them.

{
  "$schema": "https://json.schemastore.org/web-manifest-combined.json",
  "id": "/",
  "name": "Zero Signup Tools",
  "short_name": "ZS Tools",
  "description": "Free browser tools for developers, writers, and designers.",
  "start_url": "/?source=pwa",
  "scope": "/",
  "display": "standalone",
  "orientation": "portrait",
  "theme_color": "#0b1220",
  "background_color": "#05070b",
  "icons": [
    {
      "src": "/icons/icon-192.png",
      "sizes": "192x192",
      "type": "image/png",
      "purpose": "any"
    },
    {
      "src": "/icons/icon-512.png",
      "sizes": "512x512",
      "type": "image/png",
      "purpose": "any"
    },
    {
      "src": "/icons/icon-maskable.png",
      "sizes": "512x512",
      "type": "image/png",
      "purpose": "maskable"
    }
  ],
  "shortcuts": [
    {
      "name": "All tools",
      "url": "/tools"
    },
    {
      "name": "Categories",
      "url": "/categories"
    }
  ]
}

Plain-text report

A summary you can paste into a pull request, ticket, or changelog so reviewers can see the same findings.

# Web App Manifest validation report

Findings: 0 error(s), 0 warning(s), 1 info note(s).

Install criteria: 5 of 5 required, 6 of 6 total.
Installable: yes.

## Notes
- screenshots: screenshots is missing. Recommended; Chrome shows a richer install dialog when screenshots are declared.

## Install checklist
[x] Has a name or short_name 
[x] Has a start_url 
[x] display is standalone, fullscreen, or minimal-ui 
[x] Has a 192x192 icon with purpose any (or larger) 
[x] Has a 512x512 icon with purpose any (or larger) 
[x] Has a maskable icon (recommended)

How to use

Paste the contents of your manifest.json or .webmanifest file into the input area. Use Load valid sample to see a passing manifest, or Load sample with issues to see what every kind of finding looks like.
Read the Summary cards for the count of errors, warnings, and notes, and whether the manifest passes the install criteria.
Work through the Install criteria checklist. The first five rows must pass for Chrome and Edge to show the install prompt. The maskable icon row is a recommendation for adaptive Android tiles.
Fix each Error, then Warning, then Note finding. Each row shows the field path, a plain-language explanation, and where available a suggested fix.
Use Copy JSON to grab the normalized manifest with keys reordered into the documented PWA order. Use Copy report to grab a plain-text summary for a pull request, ticket, or changelog.

About this tool

Web App Manifest Validator runs a complete check of your manifest.json (also called .webmanifest) against the W3C Web App Manifest specification and the install criteria Chrome and Edge actually enforce before showing the browser install prompt. Paste the file contents into the input and the validator parses the JSON, then walks every documented member: name, short_name, description, start_url, scope, id, display, display_override, orientation, theme_color, background_color, icons, screenshots, shortcuts, categories, lang, dir, prefer_related_applications, related_applications, share_target, file_handlers, protocol_handlers, launch_handler, handle_links, edge_side_panel, iarc_rating_id, scope_extensions, note_taking, widgets, and tab_strip. Type mismatches (string expected, got number), enum violations (display must be standalone, fullscreen, minimal-ui, or browser; orientation must be one of eight documented values), invalid CSS colors (theme_color and background_color accept named colors, hex, rgb, rgba, hsl, hsla, hwb, lab, lch, oklab, oklch, and color()), URL parsability problems, and cross-field consistency issues (start_url must be inside scope; icons must include both a 192x192 and a 512x512 entry with purpose any for installability) are all reported with the exact field path, a plain-language explanation, and a copy-ready fix. The install checklist mirrors the Chrome and Edge criteria: name or short_name set, start_url set, display one of standalone, fullscreen, or minimal-ui, plus the 192x192 and 512x512 icon coverage, and recommends a maskable icon for adaptive Android home screen tiles. Deprecated keys (serviceworker, gcm_sender_id, permissions, splash_screens) are surfaced with the modern replacement so old manifests can be migrated cleanly. A normalized JSON output reorders keys into the conventional PWA documentation order, ready to paste back. Everything runs locally on your device. The manifest you paste, including app names, URLs, brand colors, shortcut targets, and screenshot paths, never leaves your browser.

Free to use. Works in your browser. No signup, no login.

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