Open Source LLM Observability & Evaluation using Vitest
A curated collection of the best open source tracing, monitoring, and evaluation platforms for LLM and AI-agent applications. using Vitest.
Open source LLM engineering platform for AI-powered applications
Stars
Stars growing over the last 30 days36,359Last commit
8 hours agoLicense
MIT
Langfuse provides tracing, evaluations, prompt management, and analytics to debug and improve LLM applications.
Open Source Alternative to:
Open-source LLM tracing & evaluation for AI optimization
Stars
Stars growing over the last 30 days11,985Last commit
6 hours agoLicense
Elastic-2.0
Open-source platform for LLM tracing, evaluation, and optimization. Features automatic instrumentation, prompt playground, and real-time AI application monitoring.
Open Source Alternative to:
Full observability for AI agents in production
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4,735Last commit
15 hours agoLicense
MIT
Open-source platform for monitoring AI agents: captures traces, surfaces failure patterns, alerts on issues, and helps you verify fixes with automated evals.
Open Source Alternative to:
Simulation-based testing and evaluation for AI agents
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4,991Last commit
3 hours agoLicense
Apache-2.0
Tests AI agents through multi-turn simulations, LLM-based scoring, and production tracing so teams can ship reliable agents with confidence.
Open Source Alternative to:
LLM observability: cost, latency, and traces in one place
Stars
13Last commit
6 days agoLicense
MIT
Drop-in observability platform for OpenAI, Anthropic, and Gemini that logs every request, tracks costs, traces agent workflows, and flags anomalies and PII.
Open Source Alternative to:
c15t – Open-source cookie banner, built for control and lightening fast modern web apps.
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