OpenAI will watermark ChatGPT text in the EU but makes it optional for API users worldwide

OpenAI is adding invisible watermarks to ChatGPT text to comply with EU rules. Unlike Anthropic, it will let API customers worldwide turn them off. The EU AI Act reportedly requires AI providers to label generated text in a machine-readable format. OpenAI's answer is textGrain, a technology that embeds an invisible statistical signal in the model's word choices. It works much like Claude's SynthID watermark, which uses Google's open-source technology. OpenAI says it will turn on watermarking for ChatGPT and Codex users in the European Union over the coming weeks. API watermarking will be opt-in worldwide, unlike Anthropic's mandatory watermarking for Claude, which applies globally regardless of how users access the models. OpenAI's API watermarking will also be available through cloud partners such as Microsoft Azure in the coming weeks.