{"data":{"slug":"langsmith","name":"LangSmith","tagline":"LangChain freemium obs/eval/deploy — free Developer 5k traces/mo","category":"agents","categoryName":"AI Agents","url":"https://www.langchain.com/langsmith","github":"https://github.com/langchain-ai/langsmith-python","pricing":"freemium","hook":"LangSmith is LangChain’s agent observability, evaluation, and deployment platform — start on the free Developer seat, then pay as traces grow.","whatsGood":"Freemium (docs.smith.langchain.com / langchain.com/langsmith). Tracing, evals, prompt hubs, and deployment hooks wired for LangChain/LangGraph (and broader OpenTelemetry-style ingest). Developer plan: $0/seat with ~5k base traces/mo then pay-as-you-go; Plus/Enterprise for teams. SDKs are MIT: Python at langchain-ai/langsmith-python and JS/TS at langchain-ai/langsmith-javascript (both moved out of the langsmith-sdk repo, archived on 16 Oct 2026).","theCatch":"The product is hosted freemium (self-host exists on higher plans) — not a MIT self-host default like Langfuse. Vs Langfuse / Braintrust / Arize Phoenix: LangSmith is the LangChain-native commercial control plane; Langfuse is OSS self-host; Braintrust is eval-first; Phoenix is ELv2 Arize. Free tier is real but thin for busy agent fleets — budget traces early.","verdict":"Freemium LangChain obs/eval when the LangGraph stack wants one vendor pane — not Langfuse MIT self-host; free until ~5k traces.","addedAt":"2026-09-29","featured":false,"domain":"AI Agents","subSpecialty":"Agents","subcategory":"Evals & Tracing","tags":["free-tier","paid-led","permissive","evals","observability","active"],"capabilities":[],"surfaces":["Hosted"],"ecosystem":["Multi-platform"],"licenseModel":"Freemium","githubStars":13,"starsPerWeek":0,"access":"paid-led","archived":false,"repo":{"createdAt":"2026-02-20","pushedAt":"2026-10-17","license":"MIT","archived":false,"checkedAt":"2026-10-19"}},"related":[{"slug":"claude-code","name":"Claude Code","tagline":"Terminal-first coding agent with deep repository context"},{"slug":"cursor","name":"Cursor","tagline":"The AI-first code editor that understands your codebase"},{"slug":"devin","name":"Devin","tagline":"Autonomous AI engineer for defined engineering tasks"},{"slug":"stagehand","name":"Stagehand","tagline":"AI-native browser automation that mixes code and natural language"},{"slug":"browser-use","name":"Browser Use","tagline":"Open-source framework for LLM-driven browser agents"}],"links":{"self":"/api/gems/langsmith","html":"/gems/langsmith","markdown":"/gems/langsmith.md","category":"/api/gems?category=agents","categoryPage":"/stacks/agents"}}