Heat Signature

Demonstrate human authorship by analyzing keystrokes without ever seeing the text. Works with Google Docs, more platforms soon to follow.

Instead of judging authorship from writing style, Heat Signature examines the timing of the keystrokes and revision patterns without ever seeing the words themselves. Because these signals are already present in Google Docs revision history, it works for documents composed before the extension was installed. The extension is never recording and does not need to be activated at the time of composition.

The result is a sharable URL that can verify the authorship of your text without exposing any of the editing history. We also offer an SDK to seamlessly include a badge and a link next to your content.

The goal is to help writers proactively indicate that they did not use AI in their work. It also works on documents shared with the user and can indicate if the original author used outside assistance. In cases where the model detects any issues, it can provide private feedback on the specific reason for its reservations.

Private by design. Verifiable without exposing edit history. We can help you show you did the work.

— How to Use —

After installing in Chrome:

1️⃣ Click the puzzle-piece Extensions icon
2️⃣ Pin Heat Signature
3️⃣ Open any Google Doc in Chrome
4️⃣ Click the Heat Signature icon while viewing your doc
5️⃣ Follow the prompts in the extension page

— How It Works—

• Analyzes Google Docs revision history, first removing the characters in each keystroke
• Words cut and paste from other parts of the document retain their provenance as original
• Before evaluation, provides an opportunity to source any external pasted blocks (e.g., quotations, excerpts)
• Uses a transparent scoring system powered by a proprietary model to verify human authorship
• Provides a private analysis of results, including specific reasons if a document does not pass
• Generates a sharable URL that others can use to verify a text is human authored

Heat Signature does NOT see or store the text of your documents. For verification, it saves only cryptographic fingerprints derived from the text.

Research submission is optional. You can review a report locally without submitting a document for analysis by the model.

— What Heat Signature may access —

When you run the extension on a Google Doc, it accesses revision-history data needed for analysis, including edit timing, edit order, insert/delete operations, edit positions, edit sizes, and a Google Docs document identifier that is hashed into a unique ID that does not identify the original document without explicit consent.

The extension only runs on Google Docs document edit pages.

— Who it is for —

Heat Signature is currently intended for writers, editors, researchers, teachers, and early testers who want a more transparent way to evaluate writing provenance.

This is pre-release software. Results should be treated as evidence to review, not as an automatic accusation or final judgment. Heat Signature is designed to support human review, not replace it.

— Current limitations —

Heat Signature currently works with Google Docs. It depends on the revision data available from the document and may not be suitable for every writing workflow. Reports can surface suspicious patterns, but they cannot prove every possible explanation for how a document was written.

— Learn more —

Privacy Policy: https://heatsig.io/privacy/
Plain-language privacy overview: https://heatsig.io/your-privacy/
Website: https://heatsig.io/
Contact: chris@heatsig.io