The Marvellous Suspender is a free, open-source Chrome extension for anyone who keeps too many tabs open and wants their browser's memory and CPU given back, without ads or tracking of any kind.

What it is

The Marvellous Suspender is a browser extension, written in JavaScript and released under the GNU General Public License v2, that lives inside Google Chrome and watches how long each open tab has gone unused. Once a tab crosses a default or user-configurable idle interval, the extension suspends it. Suspension tears down the resources the tab was holding, so the memory and CPU it occupied are returned to the machine. The project is built on Manifest V3 and requires Chrome 110 or later.

The concrete problem it solves is tab bloat. A browser with dozens of open tabs keeps every one of them resident, and the machine slows down even though most of those tabs are not being looked at. This extension replaces The Great Suspender, the extension it was derived from: the codebase was cleaned up and is actively maintained, with the source published under GPL-2.0 so anyone can audit or fork it. It sits in the Chrome extension ecosystem, distributed both through the official Chrome Web Store and as buildable source.

Key capabilities

• Automatic suspension of tabs after a default or user-configurable idle interval, freeing the memory and CPU those tabs were consuming.
• Manifest V3 build, requiring Google Chrome 110 or later.
• Distribution through the official Chrome Web Store under extension ID noogafoofpebimajpfpamcfhoaifemoa.
• Manual install path: load the src directory unpacked via chrome://extensions/ with Developer mode enabled.
• Reproducible build from source using npm install, npm run generate-key, and npm run build, producing output in build/crx/ and build/zip/.
• Localization through Crowdin at crowdin.com/project/tms, covering browser-extension internationalization.
• A documented permission model, with the required permissions explained at kb.marvellouscode.works/docs/TMS/permissions.

Who uses it and how

• Individuals running Chrome with many tabs open on memory-constrained machines, where suspended tabs return RAM and CPU to the rest of the system.
• Users who want a maintained alternative to The Great Suspender and prefer an extension with no advertising and no tracking.
• Privacy-conscious or policy-constrained users who install the unpacked build from source rather than pulling from the Chrome Web Store.
• Contributors submitting pull requests for features and bug fixes; the project asks that new features start as an issue so the approach can be discussed first.
• Translators working through Crowdin to close localization gaps, with English and Italian maintained directly and other languages open for native-speaker review.

Getting started

Install from the official Chrome Web Store, or download the latest release, unarchive it, enable Developer mode at chrome://extensions/, and use Load unpacked extension pointing at the src directory. Building locally needs openssl and npm, then npm install, npm run generate-key, and npm run build, which leaves a .crx in build/crx/.

How it compares

Against The Great Suspender, which it is explicitly based on, the distinguishing claims are a cleaned-up codebase and active maintenance. It is licensed GPL-2.0 and self-hostable from source, so the code can be inspected and built independently rather than taken on trust. No price applies: it is free, with no ads and no tracking.

When to use it — and when not to

A self-hoster needs Node and openssl to run the build, and then must manage Chrome's refusal to enable an unpacked .crx by extracting the .zip from build/zip/ instead — friction that users of the Chrome Web Store listing avoid entirely. Only English and Italian translations are maintained directly and can be relied upon; other languages were recently filled in with AI assistance and have not had a native-speaker review pass. Anyone who cannot tolerate those caveats, or who needs a tree of suspended tabs preserved across an uninstall, should look elsewhere — the README warns that suspended tabs are removed permanently if the extension is uninstalled without unsuspending them first.

npm install
npm run generate-key
npm run build

Done, without errors.