Chrome extension Manifest v3 — check your manifest free

Checks manifest.json against Manifest V3 and Chrome Web Store upload rules: MV2 leftovers, host patterns in permissions, remote code, field limits. Runs entirely in your browser — nothing is uploaded.

{
  "manifest_version": 2,
  "name": "Tab Saver Pro - save, sync and restore every open tab across all of your Chrome windows and devices",
  "short_name": "Tab Saver Pro Sync",
  "version": "1.0.0-beta",
  "description": "Saves and restores your open tabs.",
  "icons": { "16": "icons/16.png", "48": "icons/48.png" },
  "browser_action": { "default_popup": "popup.html", "default_title": "Tab Saver" },
  "background": { "scripts": ["background.js"], "persistent": false },
  "content_security_policy": "script-src 'self' https://cdn.jsdelivr.net; object-src 'self'",
  "permissions": [
    "tabs",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "*://*/*",
    "https://api.tabsaver.example/*"
  ],
  "optional_permissions": ["https://*.googleapis.com/*"],
  "web_accessible_resources": ["injected.js", "icons/48.png"],
  "content_scripts": [
    {
      "js": ["https://cdn.jsdelivr.net/npm/jquery@3/dist/jquery.min.js", "content.js"],
      "run_at": "document_idle"
    }
  ],
  "externally_connectable": { "matches": ["*://*/*"] },
  "update_url": "https://clients2.google.com/service/update2/crx",
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA"
}

as of

Free here: Open any manifest.json and see every Manifest V3 and Chrome Web Store upload blocker in it, with the exact replacement for each line.. In the editor: Scan every manifest.json in the workspace in one run and export the pre-submission report as a file you keep (Markdown + JSON) for CI and for your reviewer. — that part asks for a licence key.

Same engine as the VS Code extension, byte for byte.