Open Source Alternatives
Open Source Observability Alternatives to LangSmith
LangChain's hosted platform for tracing, evaluating, and monitoring LLM applications and AI agents in production.
LangSmith is a trademark of its respective owner.
Updated Sep 2026
What you gain
- ✓Trace and eval data stays on your own infrastructure, not LangChain's cloud
- ✓No per-seat fee as your team grows past the free tier
- ✓Works with any framework, not just LangChain and LangGraph
- ✓Full control over data retention and PII handling
What you give up
- △No managed Prompt Hub or hosted annotation queues out of the box
- △Lose LangSmith's one-click LangChain and LangGraph trace instrumentation
- △You run and scale the trace storage yourself
- △No vendor SLA or dedicated support engineer
Switching Cost
Switching off LangSmith means swapping the LangSmith SDK for another tracing client and re-pointing your instrumentation, then standing up a self-hosted backend like Langfuse or Phoenix. A solo dev on one app can move in a day or two; a small team with several agents in production should budget a week to re-instrument and validate parity. The hidden cost is your historical trace and evaluation datasets: they don't come with you, so you either export what you can or accept starting your observability history fresh.
| Langfuse | phoenix | latitude-llm | |
|---|---|---|---|
| Overlap | 70% | 65% | 60% |
| Migration | moderate | moderate | moderate |
| License | MIT License | Other | LGPL-3.0 |
| Best for | Small teams | Small teams | Small teams |
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Drop-in Replacements
Ranked by feature coverage
Langfuse
8670% coverageOpen source LLM engineering platform
Langfuse is the observability platform for LLM applications. Instrument your code with a few SDK lines and every call becomes a trace: prompts, completions, latency, token costs, quality scores over time.
phoenix
7665% coverageAI Observability & Evaluation
Phoenix is how you see why an LLM feature misbehaved. It traces every model call your app makes, captures the prompts and responses, and lets you score outputs with evals so you can tell whether last week's prompt change helped or hurt.
latitude-llm
7360% coverageLatitude is the open-source ai monitoring platform.
Latitude watches your AI agents the way Datadog watches your servers. When you ship an app built on LLMs, you lose visibility the moment a prompt leaves your code, you can't see why an agent went off the rails or which step failed.
Building Blocks
LangSmith is a platform. It bundles multiple capabilities into one subscription. These tools each cover one piece. Teams often assemble 2–3 of them instead of paying for the full suite.