Privacy Policy

Last updated: 8 October 2026

ProofKey is a browser extension published by Jiru Labs. This policy describes what it does with your data. It is short because the extension does very little.

ProofKey has no backend. There is no ProofKey server, no ProofKey account, and no analytics. Jiru Labs does not receive your text, your API keys, or any record that you used the extension.

When you run an action, ProofKey sends the text you selected — or the sentence you just finished typing — to the LLM provider you configured, at the base URL you configured, using your own API key. That request goes directly from your browser to that provider. It does not pass through any machine operated by Jiru Labs.

Which provider that is, is entirely your choice. If you point ProofKey at a local model such as Ollama, nothing leaves your machine at all.

Chrome's built-in model sends nothing. In Google Chrome, a fresh install of ProofKey uses the language model Chrome keeps on your computer. Your text is handed to Chrome on the same machine and the check runs there; ProofKey makes no network request for it. Chrome downloads that model once, from Google, when you click Download model. What Chrome itself records about the download or about using its model is governed by Google's Chrome privacy notice, not by this policy.

A model inside the browser sends nothing either (since version 0.1.11). For browsers without Chrome's model, such as Brave, ProofKey can run a language model itself, on your computer's GPU. Your text never leaves the browser for it. The model's files are downloaded once — 2.4 GB, from huggingface.co, pinned to one published revision — and only when you click Download model in settings; ProofKey says the size and the host on that button before anything is fetched. That download is a request from your browser to Hugging Face, which sees it as any website sees a visit, under Hugging Face's own privacy policy. No text you check is part of it, and nothing is fetched again after it.

Your text is then subject to that provider's privacy policy, not this one. Providers differ enormously in whether they retain prompts or train on them. That is worth reading before you paste anything confidential into a field on a site where ProofKey is enabled.

Stored using the browser's own extension storage, on your device:

• your API keys and connection settings (base URL, model, headers);
• your actions and their prompts, including any you wrote;
• your keyboard shortcuts and the list of origins they run on;
• your writing profile: style guide, terms never to flag, first language;
• if you downloaded the in-browser model, its files, in the browser's storage for the extension. Remove the downloaded model in settings deletes them.

All of the settings above — your API keys included — are kept in chrome.storage.sync (src/core/storage.ts). If you are signed in to the browser with Chrome Sync switched on for extensions, the browser copies them through your Google account's sync servers to your other signed-in browsers. That is the browser's mechanism and its provider's policy; ProofKey neither operates nor can read that channel. With Sync off, or not signed in, they stay on this computer. The downloaded in-browser model never syncs.

Your API keys are also copied to chrome.storage.local, by connection, and the copy is removed when you clear a key (since 0.1.14). This copy is the first step in keeping keys off the browser's sync: sync still holds them for now, so this changes nothing about where they travel. Since 0.1.16, the copy is also kept when settings arriving from sync carry the mark a later release will write when it stops putting keys there, so a computer that receives those settings keeps its key instead of losing it.

One more thing is kept, in chrome.storage.local, which never syncs: how many suggestions you have applied, when you applied the first, and whether ProofKey has asked you to rate it (src/core/review.ts). It exists for one purpose — asking once, after at least 10 applied suggestions over at least two days, whether you would leave a rating in the Chrome Web Store — and it is never sent anywhere. Clicking Rate ProofKey opens the store's reviews page in a new tab; nothing else happens, and ignoring it means it is not asked again.

Nothing is stored anywhere else. Uninstalling the extension removes it.

• No telemetry, analytics, crash reporting, or usage statistics. The one count described above stays on your device and is only read by ProofKey itself.
• No advertising, and no data sold, rented, or shared with third parties.
• No reading of pages you have not enabled it on.
• No collection of browsing history, credentials, or form data.

What ProofKey protects you from, and what it does not, in the terms Privacy Guides uses for common threats.

It protects against:

• Surveillance as a business model, on the part of the tool itself. Jiru Labs runs no server for ProofKey: no text, key, setting or usage count reaches us, because there is nowhere for it to go. The code is MIT licensed, so this can be checked rather than taken on trust.
• Privacy from service providers, as far as you choose it. With Chrome's built-in model or the in-browser model, ProofKey sends your text nowhere: the check runs on your computer. With a llama.cpp server you host, it goes only to that server. Nothing in between is ours.
• Pages reading more than you meant. No site access is granted at install. ProofKey reads a page only where you switched it on, one site at a time.

It does not protect against:

• The provider you pick. With an API key, the text you check goes to that provider, under its own privacy policy, tied to your account and billing.
• Your browser's own sync. Settings, API keys included, travel through your Google account's sync servers if Chrome Sync is on for extensions (see above).
• The browser and the page. Chrome's built-in model is Chrome's code; the site you type into already sees what you type there; another extension, or malware on the device, can read the same fields ProofKey does.
• Being identified. ProofKey is not an anonymity tool. A provider knows who holds the key, and the one model download from Hugging Face is seen by Hugging Face like any visit.

If Jiru Labs ever offers an optional paid or hosted feature, it would be exactly that — optional, off by default, and described here before it ships. The extension's default behaviour, as described above, is not going to start sending your writing somewhere else. If that ever changed, it would be a new major version, announced in the changelog, and it would still require you to turn it on.

Questions, or a privacy problem to report: open an issue, or email help@jirulabs.com if you would rather not do it in public.

The extension is open source and MIT licensed. If you would rather verify this policy than trust it, the code is at github.com/jiru-labs/proofkey.

The same text, with its history: PRIVACY.md on GitHub.