Free Manifest V3 Generator
Generate a valid Chrome extension manifest.json in seconds. Pick permissions, content scripts, and pages — copy the result, drop it in your extension.
{
"manifest_version": 3,
"name": "My Awesome Extension",
"version": "1.0.0",
"description": "A Chrome extension built with PlugThis",
"permissions": [
"storage",
"activeTab"
],
"action": {
"default_popup": "popup.html"
},
"background": {
"service_worker": "background.js",
"type": "module"
}
}A working extension also needs the JS, HTML, and CSS that the manifest points to. PlugThis generates the whole bundle.
Build the full extension →Build the rest of your Chrome extension with PlugThis
Describe what you want in plain English. PlugThis generates a working Manifest V3 Chrome extension in under two minutes.
Open the builderWhat is manifest.json?
The manifest.json file is the heart of every Chrome extension. It tells Chrome the extension's name, version, what permissions it needs, which files run as content scripts, and what UI elements (popup, options page, icons) it provides.
Without a valid manifest, Chrome will not load the extension. Manifest V3 is the current standard — Chrome stopped accepting Manifest V2 extensions in the Web Store in 2024.
What this generator does
This tool produces a syntactically correct Manifest V3 file based on the options you select. It handles the formatting, structure, and required fields — you don't need to remember the exact JSON syntax.
The output is the same format Chrome expects: drop the generated content into a file named manifest.json at the root of your extension folder, and Chrome will recognize it on load.
When to use a manifest generator
- You're starting a new Chrome extension from scratch
- You're converting a Manifest V2 extension and want to see the V3 equivalent of your old config
- You're modifying an extension built by someone else (or by an AI tool like PlugThis) and want a clean baseline to compare against
- You're learning Manifest V3 and want to see how different options affect the output
Beyond the manifest
The manifest is one file. A working Chrome extension is usually 5–15 files including content scripts, popup HTML, popup JavaScript, background workers, icons, and stylesheets — plus the wiring between them.
This tool produces the manifest. To produce the full extension, you can either write the rest of the code yourself, or describe what you want in plain English and let PlugThis generate everything (manifest plus all the supporting code) in under five minutes.
Manifest V3 Generator — FAQ
Is the manifest this tool produces valid?
Yes. The output conforms to the Chrome Manifest V3 schema. You can drop it directly into an extension folder and Chrome will load it.
Do I need to include all permissions or just the ones I'll use?
Just the ones you'll use. Asking for permissions you don't need triggers a more aggressive Chrome Web Store review and discourages users from installing.
Will this work for Edge and Firefox extensions?
Edge yes — it uses the same Manifest V3 format as Chrome. Firefox supports Manifest V3 with some differences; most fields work, but a few advanced features differ. The generator output is Chrome-first.
What's the difference between activeTab and tabs permission?
activeTab grants access to the current tab only when the user clicks the extension. tabs grants access to all tabs all the time. Use activeTab whenever possible — it requires no permission warning.
Can I embed this generator on my own site?
Yes. Click the Embed button on the generator to get an iframe code snippet you can paste into any site.
Other free tools
Permissions Explainer
Pick a Chrome extension permission and see exactly what it allows, the risk level, and less invasive alternatives. Or paste a manifest to audit it.
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Describe a workflow you want to improve. Get 3 tailored Chrome extension ideas you can build in under 10 minutes.