Formatters & Code
Chrome Extension Manifest Validator & MV3 Preflight Tool
Audit Chrome extension ZIP packages locally. Check Manifest V3 schemas, detect remote hosted scripts, inspect sensitive permissions, and prevent rejections.
Extension package or manifest
or click to browse your computer (all scans run locally, up to 25 MB)
Results
What the result means
This tool performs client-side preflight audits on Chrome extension ZIP packages and manifest.json files before submission to the Chrome Web Store. It validates required Manifest V3 structures, flagging deprecated background scripts and browser action declarations that cause instant store rejection. The scanner inspects your permissions array, alerting you to host match patterns that must reside in host_permissions, flags sensitive APIs such as tabs and cookies that require single-purpose justification, scans packaged HTML and JavaScript files for banned remote script tags and dynamic eval calls, and confirms all declared icons, popups, and service workers exist inside the uploaded archive.
Related tools
Guides
Questions
Why does Chrome Web Store reject extensions using Manifest V2?
Google has officially deprecated Manifest V2 in favor of Manifest V3 to enhance user security, privacy, and performance. Submissions using manifest_version 2 are blocked automatically during dashboard upload.
What is the difference between permissions and host_permissions in Manifest V3?
In Manifest V3, host match patterns like https://*.example.com/* must be declared under host_permissions rather than permissions. Misplacing host patterns under permissions causes manifest validation errors.
What is the remote hosted code policy in Manifest V3?
Manifest V3 strictly mandates that all code executed by the extension must be contained directly within the packaged ZIP archive. Loading scripts dynamically via external CDN URLs or running eval() triggers immediate store rejection.