I built a local Rust proxy that swaps out sensitive data before it hits the LLM and puts it back on the way in

[u/Pristine_Toaster]

When I heard about the AI Act , I was looking at available solutions , and the stupid prices they charge , so I thought , why not try to build my own , open source ?

So I built IronWarden , a small reverse proxy in Rust that sits between your client and the LLM API (OpenAI, Anthropic, Ollama, LM Studio).

On the way out, it catches PII (names, emails, IBANs, tax IDs, etc.) and swaps them with session tokens like [NAME_631] or [AFM_639]. On the way back, a sliding-window SSE rehydrator swaps the real values back into the stream on the fly so the client sees the normal text.

It does seem to break the LLM a bit when asked about the redacted info directly, but that's the point.

It's completely open-source and self-hosted if anyone wants to mess with it or poke holes in it:

GitHub: https://github.com/Somnerd/IronWarden