OpenAI Adds Text Watermarking to ChatGPT and Codex for EU AI Act Compliance

OpenAI is rolling out text watermarking across ChatGPT and Codex as part of its approach to EU AI Act text provenance requirements, embedding invisible signals into AI-generated outputs to indicate their synthetic origin. The watermarking system is designed to be robust against common text modifications and aims to help downstream platforms and regulators identify AI-generated content at scale. For developers building applications on top of OpenAI APIs, this means outputs may carry embedded provenance metadata that could affect downstream text processing pipelines or content moderation systems. Teams building in the EU or serving EU users should review how watermarked outputs interact with their existing workflows and disclosure obligations. This is one of the first major concrete technical compliance moves in response to the EU AI Act's content transparency mandates.