About textgrain.si

textgrain.si is a small independent site about AI text watermarks. We make free tools that run in your browser, and we write simple guides about what watermarks like textGrain can and cannot do.

Why this site exists

When OpenAI announced textGrain on 5 October 2026, people had questions right away. Is my text marked? Can someone check it? Can I remove it? Do I need to label things now? Many answers online were wrong. Some sites even sell tools that say they detect a watermark only OpenAI can read. We wanted one place with honest answers.

Our rules

• We never claim to detect textGrain. Only OpenAI’s detector, with its secret key, can.
• Every number has a source. Numbers from OpenAI are marked as OpenAI’s. Our own estimates are marked as estimates.
• Your text stays with you. Every tool runs in your browser. Nothing is uploaded.
• No tools to beat watermarks. We explain how watermarks hold up, but we do not build tools to get around them.

Where our facts come from

OpenAI’s announcement and technical report, as covered by TechCrunch, BleepingComputer, 9to5Mac and Search Engine Journal. The text of the EU AI Act and the European Commission’s guidance on Article 50. Google DeepMind’s SynthID Text paper. And the 2023 paper by Kirchenbauer and others for the method used in our demo.

We are independent

We are not affiliated with OpenAI, Google or Anthropic, and they do not support or pay us. textGrain is the name OpenAI uses for its watermark. We only use the name to talk about it.

Found a mistake?

This topic changes fast. If something here is wrong or old, email [email protected] with a link to your source, and we will fix it.