ChatGPT introduces invisible text watermarks in the EU, though they're not hard to remove

OpenAI is implementing textGrain, an invisible text watermarking system for ChatGPT and Codex users within the European Union to comply with the EU AI Act. This system ensures AI-generated content is machine-identifiable. While EU users will receive these watermarks automatically in the coming weeks, API customers worldwide can opt in to the feature starting October 5, 2026. Although the system is being rolled out, reports indicate that these invisible watermarks are not difficult to remove.