LangSmith

Build and deploy LLM applications with confidence

★★★★★ 4.8/5 from 19 reviews

AI Infrastructure Tools AI Metrics and Evaluation

What is LangSmith?

LangSmith is a platform to help developers close the gap between prototype and production. It’s designed for building and iterating on products that can harness the power–and wrangle the complexity–of LLMs.

Pros & Cons

Pros

Monitoring AI model performance
Chain sequence debugging
Evals
Annotation queues
CI/CD integration
Comprehensive visibility
Datasets
Easy to use
Flexibility outside LangChain
LangGraph
Metadata filtering
Python SDK
Real-time analytics
Time-saving
Tracing tools
Versioning

Cons

Filters not persisted in URL
UI issues with large datasets

Tool Details

Categories	AI Infrastructure Tools, AI Metrics and Evaluation
Website	www.langchain.com
Platforms	Web
Social	Twitter · GitHub

Recent Reviews (6)

Dan Jul 16, 2025

★★★★★

We started building Ting without LangSmith and we were flying blind. Diagnosing issues downstream felt like guesswork. Since bringing LangSmith in, we’ve been able to trace problems through the entire prompt path and actually understand what’s going on. We’re still evolving how we use it, but even early on it’s helped us move faster and get closer to that “this feels good” moment.

Kyle Jun 23, 2025

★★★★★

We absolutely could not build this product with LangSmith for traces, datasets, annotation queues, and evals. We've become big power users! I use to build AI apps before nice tracing tools like this existed and it's like night and day having a tool like this. We considered Langfuse, but I already had experience with LangSmith so for speed purposes we went with LangSmith.

Evals Tracing tools Datasets Annotation queues

Kanishk Aug 16, 2025

★★★★★

Promptius <3 Langchain + Langgraph + Langsmith, this combination has been instrumental in building Promptius in the past 5 months! The abstractions provided by Langchain and Langgraph make building agents as easy as writing a prose. Langsmith provides unmatched observability and also help track our costs.

Hannah Jan 27, 2025

★★★★☆

I've been using LangSmith for a couple of months at our startup and it's been incredibly useful for running ongoing LLM evaluations and for evaluating new features. The Python SDK is handy and we've automated LangSmith evals as part of CI/CD on GitHub to spot regressions. My main struggle with LangSmith has been that the UI can be tricky to work with for larger datasets or datasets with a large experiment history. I would also love for the filters to be persisted in the URL. That way I can send a filtered set of failing examples to someone without having to provide instructions for how to reconstruct it.

CI/CD integration Python SDK Evals UI issues with large datasets Filters not persisted in URL

Raffaele Jun 9, 2024

★★★★★

I've loved using LangSmith! It's efficient and user-friendly, making it a joy to work with. The platform's comprehensive visibility into the chain sequence of calls simplifies debugging and enhances the development process.

Comprehensive visibility Chain sequence debugging

Maryam Oct 6, 2025

★★★★☆

LangSmith has made it so much easier to take my LLM projects from idea to production. The debugging and iteration tools save me tons of trial and error.

Easy to use Time-saving Chain sequence debugging