OpenAI is adding text watermarking in ChatGPT and Codex

The Verge News

Summary

OpenAI is introducing invisible text watermarks called textGrain to ChatGPT and Codex for EU users to comply with the EU AI Act, with opt-in watermarking for API customers worldwide and detector access for approved researchers.

<figure> <img alt="Open AI logo on a graphic green backround." data-caption="" data-portal-copyright="Image: The Verge" data-has-syndication-rights="1" src="https://platform.theverge.com/wp-content/uploads/sites/2/2025/10/STK155_OPEN_AI_CVirginia__C.jpg?quality=90&#038;strip=all&#038;crop=0,0,100,100" /> <figcaption> </figcaption> </figure> <p class="wp-block-paragraph">An <a href="https://openai.com/index/eu-text-provenance/">invisible, machine-readable watermark</a> in text output is rolling out to ChatGPT and Codex, but only for users in the European Union at first. </p> <p class="wp-block-paragraph">OpenAI says its textGrain watermarking "matched or exceeded" other approaches like Google DeepMind's SynthID for text, which is also the basis for the watermarking Anthropic <a href="https://www.theverge.com/ai-artificial-intelligence/980869/anthropic-claude-watermarks-synthid-text-system">announced in August</a>. Like OpenAI, Anthropic made the move to meet the requirements of the <a href="https://www.theverge.com/ai-artificial-intelligence/974571/eu-ai-act-transparency-labels-rules-deepfakes">EU's AI Act</a>; however, not everyone was happy to learn about the addition.</p> <p class="wp-block-paragraph">OpenAI also included scores from AI benchmarks showing similar performance from watermarked and unwatermarked text. But it notes that textGrain "does not guarantee …</p> <p><a href="https://www.theverge.com/ai-artificial-intelligence/1004880/openai-chatgpt-text-watermarks-eu-ai-act">Read the full story at The Verge.</a></p>
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# OpenAI is adding text watermarking in ChatGPT and Codex Source: [https://www.theverge.com/ai-artificial-intelligence/1004880/openai-chatgpt-text-watermarks-eu-ai-act](https://www.theverge.com/ai-artificial-intelligence/1004880/openai-chatgpt-text-watermarks-eu-ai-act) [![Stevie Bonifield](https://platform.theverge.com/wp-content/uploads/sites/2/2025/10/STEVIE_BONIFIELD_BLURPLE.jpg?quality=90&strip=all&crop=0%2C0%2C100%2C100&w=96)](https://www.theverge.com/authors/stevie-bonifield) Stevie Bonifield is a news writer covering all things consumer tech\. Stevie started out at Laptop Mag writing news and reviews on hardware, gaming, and AI\. An[invisible, machine\-readable watermark](https://openai.com/index/eu-text-provenance/)in text output is rolling out to ChatGPT and Codex, but only for users in the European Union at first\. OpenAI says its textGrain watermarking “matched or exceeded” other approaches like Google DeepMind’s SynthID for text, which is also the basis for the watermarking Anthropic[announced in August](https://www.theverge.com/ai-artificial-intelligence/980869/anthropic-claude-watermarks-synthid-text-system)\. Like OpenAI, Anthropic made the move to meet the requirements of the[EU’s AI Act](https://www.theverge.com/ai-artificial-intelligence/974571/eu-ai-act-transparency-labels-rules-deepfakes); however, not everyone was happy to learn about the addition\. OpenAI also included scores from AI benchmarks showing similar performance from watermarked and unwatermarked text\. But it notes that textGrain “does not guarantee reliable detection,” and says text watermarks don’t verify accuracy, determine who owns the text, measure how much a human contributed, or prove human authorship\. > **Rolling out text watermarking in the EU\.**Over the coming weeks, we will introduce text watermarking to eligible ChatGPT and Codex users across all plans in the EU only\. We are not making text watermarking a global default at launch\. This regional approach gives us room to learn from real\-world use and feedback\. **Enabling opt\-in watermarking for API customers\.**Starting today, API customers around the world will be able to opt in to watermarked text outputs for select models\. This lets customers decide how watermarking fits their transparency obligations and the experiences they provide to users\. We are also working with cloud partners to make watermarking available for OpenAI model outputs accessed through their services in the coming weeks\. **Providing detector access to researchers and expert organizations\.**Approved researchers and expert organizations can apply starting today\. In accordance with the Code of Practice, access will be initially granted on a case\-by\-case basis to support evaluation and improvement of text provenance\. The tool will report whether it detects an OpenAI watermark, without identifying the user or revealing their prompts or conversations\. Given the risk of missed watermarks and false positives, we are not making it publicly available at launch\. **Follow topics and authors**from this story to see more like this in your personalized homepage feed and to receive email updates\. - Stevie Bonifield

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