Langfuse Has a Free API — Open-Source LLM Observability and Tracing

What if you could trace every LLM call — input, output, latency, cost, and feedback — in one dashboard?

Langfuse is open-source LLM observability. Like Datadog for AI apps.

• Tracing — every LLM call with cost and latency
• Prompt management — version and A/B test prompts
• Evaluations — model-based and human scoring
• Free tier — 50K observations/month

An AI startup discovered one feature used 60% of tokens for 5% of users. Optimized prompt, costs dropped from $3K to $1.2K/month.

Visit langfuse.com — open source, self-hostable.

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