Sidecar Grammar — Privacy Policy
Last updated: 17 August 2026
Sidecar Grammar is a browser extension that checks grammar entirely on your device.
Summary
Nothing you type is ever collected, stored remotely, or transmitted. The only information that ever leaves your device is a small, non-identifying record sent if you uninstall the extension, described in full below.
How your text is handled
All grammar checking runs locally in your browser using an on-device engine (the open-source Harper WASM engine). The text you type into fields is analysed on your own device and is never sent to any server, and never leaves your browser.
What is stored
Three things, all in your browser's local extension storage:
- your settings — whether the extension is enabled, and which sites you have turned it off for
- the date the extension was installed
- whether you have ever applied a correction
The first never leaves your device at all. The other two are used only to populate the uninstall feedback page described below.
While the extension is running
No analytics, no telemetry, no tracking. No account, no sign-in. The extension makes no external network requests while running — the grammar engine is bundled with the extension itself, not downloaded.
If you uninstall the extension
When you remove Sidecar Grammar, Chrome opens a short feedback page. Opening that page sends the following to a server operated by the developer:
- the extension version
- how many days the extension was installed
- whether you ever applied a correction
That is all. It does not include any identifier, any account, anything you typed, or which sites you used it on. There is no way to link this record to you or to any other record.
The feedback page itself asks one optional multiple-choice question and offers an optional free-text box. It requires no email address, no account, and no personal details. You can close the page without answering, and nothing further is sent.
This information is stored in a database operated by the developer, hosted with Supabase in Sydney, Australia. It is used only to understand why people stop using the extension.
Permissions
Site access is requested only after you explicitly click Enable. This access is used solely to read text from editable fields so grammar checking can run on your device. Nothing you type is persisted or transmitted.
Changes
Any change to this policy will be published at this address, with the date above updated.