Agentic Index
Langfuse vs Wandb Weave (2026)
Both trace, evaluate and monitor agents, at 7.5 and 7 of 14, and the ecosystem question decides most of these.
Langfuse is open source and self hostable with tracing, prompt management and evaluation, free for 50,000 units monthly then 29 dollars. Weave comes from Weights and Biases with session aware tracing, LLM as a judge scoring and safety scorers, free tier then about 60 dollars monthly plus usage meters. If your team already runs Weights and Biases for model training, Weave is the shorter path; if not, Langfuse is cheaper and yours to host.
Choose Langfuse if
- Documented coverage is slightly broader and open source self hosting is a requirement.
- Prompt management alongside tracing is the combination you need.
- Twenty nine dollars against sixty plus usage meters is a real difference at team scale.
Choose Wandb Weave if
- Your team already runs Weights and Biases, which makes this continuous with existing practice.
- Safety scorers alongside quality evaluation is the coverage you want.
- Session aware tracing matches how your agents actually run.
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