Build and deploy LLM apps with confidence
Unexpected results happen all the time. With full visibility into the entire chain sequence of calls, you can spot the source of errors and surprises in real-time with surgical precision.
Nested traces
Prompt-level visibility
Real-time insights
Playground mode
Test and evaluate
Software engineering relies on unit testing to build performant, production-ready applications. LangSmith provides that same functionality for LLM applications. Spin up test datasets, run your applications over them, and inspect results without having to leave LangSmith.
Monitor
Given the stochastic nature of LLMs, it can be hard to answer the simple question: “what’s happening with my application?” LangSmith enables mission-critical observability with only a few lines code.
Application-level usage stats
Feedback collection
Filter traces
Cost measurement
Performance comparison
Manage Prompts
Prompts power your team's chains and agents, and LangSmith allows you to refine, test, and version them in one place. LangChain Prompt Hub makes it easier to discover and save successful prompts for any use case, so you don't have to start from scratch.
Prompt playground
Cross-team collaboration
Catalog of ranging models & tasks
Proven prompting strategies
Turn the magic of LLM applications into enterprise-ready products
Native collaboration
Bring your team together in LangSmith to craft prompts, debug, and capture feedback.
Works seamlessly with LangChain
Go from experimentation to production with one, unified toolkit.
Incorporate best practices
We’re not only building tools. We’re establishing best practices you can rely on.
Loved by Builders
“We give our learners access to LangSmith in our LangChain courses so they can visualize the inputs and outputs at each step in the chain. This observability helps them understand what the LLMs are doing, and builds intuition as they learn to create new and more sophisticated applications.”

Geoff Ladwig
Educator at DeepLearning.AI
“LangSmith has been great to build with, specifically adding observability and testing to complex LLM apps. It was easy to integrate and the agnostic open source SDK was very flexible so we could adapt it to our implementation.”

Richard Meng
Software Engineer at Snowflake
“As soon as we heard about LangSmith, we moved our entire development stack onto it. We could have built evaluation, testing and monitoring tools in house, but with LangSmith it took us 10x less time to get a 1000x better tool.”

Jose Peña
Manager at Fintual