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Tool
Category
Pricing
Free?
Updated
LangSmith
AI Agents
Freemium
✓
Mar 2026
→
Developer platform for debugging and monitoring LangChain-based AI agent applications
Best for: LangChain
Weights & Biases Weave
AI Agents
Freemium
✓
Mar 2026
→
W&B toolkit for tracing, evaluating, and improving AI agent applications
Best for: W&B
Langfuse
AI Agents
Freemium
✓
Mar 2026
→
Open-source LLM observability platform for tracing, debugging, and monitoring AI agents
Best for: observability
Arize Phoenix
AI Agents
Freemium
✓
Mar 2026
→
Open-source AI observability tool with interactive tracing and RAG evaluation
Best for: observability