OpenAI Adds API Text Watermarking, Disabled by Default

OpenAI is introducing text watermarking for API output as it addresses EU text-provenance rules, but customers must opt in rather than receiving it automatically. The approach includes defined watermark coverage and detection, with access initially starting with researchers, making provenance a deployment choice rather than a universal API default.

• OpenAI says its text-watermarking approach covers where watermarks apply and how detection works under EU rules.
• Text watermarking is available for OpenAI API output but is off by default.
• Access to the watermark-detection capability starts with researchers.
• OpenAI’s default differs from Anthropic’s approach, which applies watermarking rather than leaving it disabled by default.

Bottom line If you generate regulated or provenance-sensitive content through OpenAI’s API, assess the opt-in watermarking path before your next compliance review.