Arize Phoenix is a free, open-source alternative to LangSmith.

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Key features

• Open-source LLM tracing and evaluation platform for AI applications.
• Monitor, debug, and optimize LLM workflows with built-in observability.
• Self-hosted deployment for full control over tracing and evaluation data.
• Supports experimentation with LLM tracing and evaluation using the Phoenix library.
• Designed for machine-learning and AI observability use cases.

Platforms

Windows, macOS, Linux

Links

• Official website
• Source code repository

Pricing

Free. The free plan includes self-hosted LLM tracing, evaluation, and experimentation with the open-source Phoenix library.