OpenAI introduces invisible text watermarking in EU to satisfy AI Act

OpenAI announced on October 5, 2026, that it will begin adding an invisible watermark to text generated by ChatGPT and Codex within the European Union. TechCrunch, the Verge, and The Next Web all reported that the rollout aims to comply with the European Union AI Act. The rules under the Act require artificial intelligence companies to mark generated content so that other systems can identify it. [1][3][6]

TechCrunch reported that the transparency provisions of the European Union AI Act took effect on August 2. The invisible watermark will roll out over coming weeks to eligible ChatGPT and Codex users across all plans in the European Union. Furthermore, developers using the OpenAI API globally can manually turn on watermarking for select models starting immediately, as it remains off by default. [1]

OpenAI noted in a blog post that editing generated text can make the invisible marks harder for systems to detect, according to TechCrunch. Separately, OpenAI announced that it will test a new visual ad format in ChatGPT that displays images during image generation tasks, as reported by The Information, GSMArena, and Digiday. [1][2][5][7]

OpenAI released ChatGPT on November 30, 2022, operating the generative artificial intelligence chatbot under a freemium model. OpenAI reached a valuation of approximately 850 billion dollars in early 2026, following the release of its large language model series. [9][10]