Who makes Simmer

Simmer is made by Addo Bari, in Tokyo.

Simmer started as Tab Butler, a small extension for keeping my own tabs in order. It grew into something else: instead of asking you to sort tabs into groups and folders, it works out what you're in the middle of and lets you put a whole task away and bring it back later. Version 4.0, renamed Simmer, went up on the Chrome Web Store on 4 November 2026.

How it's built

No account, no server. There is nothing to sign up for, and nothing of yours is sent to me. Your tabs stay in Chrome on your computer.
The model is in the box. The model that compares tab titles ships inside the extension and runs on your computer, in English and Japanese. No code is loaded from the internet.
Free, with no ads. Simmer has no paid plan and nothing to upsell.
Everything can be undone. Every action is listed under Recently with Undo, and Simmer never deletes your bookmarks.

Get in touch

Questions, bugs and ideas go to addobari31@gmail.com. If Simmer helps you, a review on the Chrome Web Store is the best way to help other people find it.