# Ombre — open source security and audit layer for LangChain apps

**URL:** <https://forum.langchain.com/t/ombre-open-source-security-and-audit-layer-for-langchain-apps/3614>\
**Category:** Talking Shop\
**Created:** [April 28, 2026, 2:15pm UTC](https://forum.langchain.com/t/ombre-open-source-security-and-audit-layer-for-langchain-apps/3614 "2026-04-28T14:15:34Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![pypl0](https://yyz1.discourse-cdn.com/flex007/user_avatar/forum.langchain.com/pypl0/32/2903_2.png) [@pypl0](https://forum.langchain.com/u/pypl0)\
**Post date:** [April 28, 2026, 2:15pm UTC](https://forum.langchain.com/t/ombre-open-source-security-and-audit-layer-for-langchain-apps/3614/1 "2026-04-28T14:15:34Z")

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Hey LangChain community,

Built Ombre — an open source infrastructure layer that adds

security, caching, and audit logging to any LangChain application.

What it adds:

- Blocks prompt injection before it reaches your chain

- Semantic cache cuts API costs 40-60%

- Catches hallucinations before users see them

- Tamper-proof audit trail — EU AI Act ready

- PII redaction before data hits the model

- Persistent memory across sessions

Runs locally — data never leaves your infrastructure.

Works alongside LangChain, not a replacement.

One line to install:

pip install git+https://github.com/pypl0/Ombre.git

GitHub: [GitHub - pypl0/Ombre: Open source AI infrastructure layer. Eight agents run on every request: security, caching, memory, hallucination detection, tamper-proof audit trail. One line of code. Your data never leaves your server. · GitHub](http://github.com/pypl0/Ombre)

Would love feedback from LangChain builders — what security

and observability problems are you hitting in production?