LangSmith
LangSmith is a developer platform for a new type of application. It offers features like observability, testing, evaluation, and monitoring tools for complex LLM (Language Model) apps.
Expert Video Review by SEOGANT · March 2026
Distribution Score: 84/100 What is this? ⓘ
What is LangSmith?
LangSmith is an LLM application development and observability platform built by LangChain that provides the tooling for building, debugging, testing, and monitoring language model applications in production.
Its tracing capability records every step of complex LLM chains and agent workflows, making the execution path of AI applications observable and debuggable in a way that raw log files cannot achieve.
The platform's evaluation framework enables systematic testing of AI application behavior: defining test datasets, running them through the application, and evaluating outputs against quality criteria.
This evaluation infrastructure is critical for AI applications where the correctness of outputs can't be verified with traditional unit tests and requires domain-specific quality assessment against representative examples.
AI engineers, ML researchers, and product teams building LLM-powered applications with LangChain or other frameworks use LangSmith to develop AI applications with engineering rigor rather than by feel.
The platform's comprehensive coverage of the AI development lifecycle from initial development through production monitoring makes it a central tool in the workflow of teams that need to build reliable, maintainable AI applications rather than one-off demonstrations.
Who is LangSmith for?
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