Web Manifest Validator — Free Online Tool Validate PWA web manifests locally for core names, icons, display, start URL, and theme metadata.
Use this free online Web Manifest Validator directly in your browser. No signup required, no data leaves your device. Part of Utilier — a collection of 133+ developer utilities.
What is Web Manifest Validator? A web app manifest is JSON metadata that tells browsers how a site should appear when installed as a Progressive Web App. It defines names, icons, start URL, display mode, theme colors, and related installation behavior. This validator checks a pasted manifest for the common fields required for a credible install experience, entirely in the browser.
A manifest affects an installed app's name, icon, launch behavior, and browser chrome, but it is only one part of a PWA. A production-ready install experience also needs correctly served icons, HTTPS, an appropriate start URL, and often a service worker. Validate the deployed file in DevTools after this local structural check.
Why use manifest validator? A PWA can install with incomplete metadata but look unpolished or fail to meet expectations on different devices. Checking key fields and common icon sizes before deployment helps catch an avoidable configuration mistake.
When to use manifest validator Use it when creating manifest.webmanifest, preparing installable web-app assets, or reviewing a PWA release. Test the final deployed manifest in browser DevTools because URL paths and MIME types are server concerns.
How to use manifest validator Paste the complete manifest JSON, then review each reported item before deployment.
Paste the manifest: Include the complete icons array rather than a partial snippet.Review core fields: Provide name, short_name, start_url, display, and icons.Check icon coverage: Include a 192x192 icon and verify every source URL in the deployed app.Test production: Use the browser Application panel to inspect the served manifest and installation experience.Key features Local JSON parsing: Processes the pasted manifest without uploading it.Core-field checks: Reports missing name, short_name, start_url, display, and icons values.Install-icon check: Flags an icons array without a common 192x192 source.Common use cases PWA release review: Catch incomplete installation metadata before releasing a site.New app setup: Build an initial manifest with a concise structural checklist.Asset migration: Review manifest settings after moving icons or changing a deployment base path.Examples Core manifest name, short_name, start_url, display, iconsReports that core fields are present.Missing icon Manifest without a 192x192 iconSuggests adding a common install icon size.Standalone app display: standalone with a root start_urlProvides metadata expected for a browser-app-style launch.Technical reference Fields checked directly, plus metadata worth confirming in the deployed application.
name The full application name used where space permits. short_name A compact name for launcher and icon surfaces. start_url The page launched from an installed app shortcut. display The intended browser-chrome presentation, commonly standalone. icons Image objects with a source, sizes, and optionally type or purpose. theme_color A browser-chrome color where supported. Common mistakes to avoid Using an icon path that works only locally Why it happens: The deployed app can have a different base path or asset location.
How to avoid it: Open the production manifest and icon URLs directly before release.
Providing only one small icon Why it happens: Installed surfaces use different dimensions and may scale a small source poorly.
How to avoid it: Provide appropriate sizes and test target devices.
Equating valid JSON with an installable PWA Why it happens: HTTPS, service workers, browser criteria, and server headers also matter.
How to avoid it: Use this structural check, then test the deployed app in supported browsers.
Frequently asked questions Does this install my PWA? No. It validates configuration text only.
Are icons required? They are strongly recommended for installed experiences.
Does it support JSON? Yes. Web manifests use JSON syntax.
Does it verify icon URLs exist? No. Inspect deployed URLs and the browser Application panel separately.
Which display value should I choose? Choose the installed experience the app supports; standalone is a common choice.
Is the manifest uploaded? No. Validation runs locally in the browser.
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