Privacy Filter is a small model with frontier personal data detection capability. It is designed for high-throughput privacy workflows, and is able to perform context-aware detection of PII in unstructured text. It can run locally, which means that PII can be masked or redacted without leaving your machine. It processes long inputs efficiently, making redaction decisions in a quick, single pass.

At OpenAI, we use a fine-tuned version of Privacy Filter in our own privacy-preserving workflows. We developed Privacy Filter because we believe that with the latest AI capabilities, we could raise the standard for privacy beyond what was already on the market. The version of Privacy Filter we are releasing today achieves state-of-the-art performance on the PII-Masking-300k benchmark, when corrected for annotation issues we identified during evaluation.

With this release, developers can run Privacy Filter in their own environments, fine tune it to their own use cases, and build stronger privacy protections into training, indexing, logging, and review pipelines.

Privacy protection in modern AI systems depends on more than pattern matching. Traditional PII detection tools often rely on deterministic rules for formats like phone numbers and email addresses. They can work well for narrow cases, but they often miss more subtle personal information and struggle with context.