Privacy policy

What CommentLayer stores, and where

Effective November 6, 2026. This policy covers the CommentLayer browser extension and the hosted layer service at commentlayer.summitml.com, both run by Summit ML. CommentLayer is open source, so everything described here can be checked against the code.

What stays in your browser

The extension keeps these in Chrome's local extension storage on your device. They are not sent to us except where noted below.

• The layers you created or joined, including each layer's invite key, and the admin key for layers you created.
• The list of sites you turned each layer on for.
• The display name you typed, your theme colors, and an admin token if you entered one.
• A random identifier generated on your device. It lets you edit and delete your own notes without an account.

What a hosted layer stores on our server

When you create a layer, we store its name and one-way hashes of its invite key and admin key. When you leave a note on it, we store:

• The text of the note and the display name you chose.
• The address of the page (host and path) the note is on.
• Where the pin sits: a CSS selector for the element you clicked, the position inside it, the element's tag, a label or text snippet from that element of up to 120 characters, and your viewport size.
• Timestamps, the review round, whether the note is resolved, and up and down votes.
• A one-way hash of your random identifier, to record which notes and votes are yours. Other people see vote counts, not who voted.

The extension does not read or send anything else from the pages you visit: no browsing history, no page contents beyond the snippet above, no form data, no cookies.

When the extension contacts our server

• When you create, join, or delete a hosted layer.
• On sites where you turned a hosted layer on: to load the layer's notes, to check for new ones about every twenty seconds, and to save what you write.

On every other site the extension sends nothing and adds nothing to the page.

Who can see your notes

Anyone who has a layer's invite link can read every note on that layer and add their own. The link is the access control, the same way a shared document link works, so send it only to people who should see the notes. Nothing is posted to the site being reviewed, and layers are not listed or searchable anywhere.

The notes are drawn on top of the page you are reviewing, in your browser. That means the page's own scripts, including any analytics or session-recording tools it runs, could technically read the notes shown there, and the full list of a layer's notes when you open it. Keep that in mind before reviewing a site you don't trust.

Opening an invite link does not join anything. The invite page shows the layer's name and waits for you to click Join.

How long we keep it

A hosted layer and everything on it is deleted automatically 30 days after the last change to it. A change is a new note, an edit, a vote, a resolve, or a new or renamed review round; opening or reading a layer does not count. The person who created a layer can delete it sooner from the extension's options page, and anyone on a layer can export its notes as CSV or JSON first. You can edit or delete your own notes at any time.

Who processes it

The hosted service runs on Cloudflare Workers and stores each layer in Cloudflare's Durable Object storage. Cloudflare handles network-level data such as IP addresses in order to deliver and protect the service; our code does not record IP addresses or build profiles of visitors. The join page and this page load their fonts from Google Fonts, which involves a request from your browser to Google. We do not sell or share your data with anyone else, and we do not use it for advertising, for creditworthiness or lending decisions, or for anything other than showing review notes to the people on a layer.

The use of information received by the extension adheres to the Chrome Web Store User Data Policy, including its Limited Use requirements.

Your own backend, and the embed

If you point the extension at a CommentLayer backend you host yourself, your notes go to that backend and never reach us. The same is true when a site embeds CommentLayer with its own backend: whoever runs that backend is responsible for the data.

Removing your data

Delete your notes from the overlay, or delete the whole layer if you created it. Removing the extension clears everything it stored in your browser. If you need a layer removed and can't do it yourself, email hello@summitml.com with the layer's invite link so we can find it.

Changes

If this policy changes, the new version will be posted here with a new effective date. Questions: hello@summitml.com.