What is
LangSmith
?
Most platform initiatives fail the same way: they start too big, get funded like projects instead of products, build for too long without testing with users, and confuse renaming an infrastructure team with building a platform team. Instead, start small, learn fast and scale deliberately.
At a glance
Attribute | Details |
|---|---|
Primary use case | Evaluate, debug, and monitor AI agents and LLM applications |
Deployment type | SaaS platform with API and SDK access |
Pricing model | Free Developer tier; Plus at $39 per seat per month plus usage; custom enterprise pricing |
API compatibility | LangSmith API and SDK interfaces for Python, Go, and JavaScript |
Supported integrations | LangChain, LangGraph, BMC HelixGPT |
Source type | Dual |
Ideal team size | Individual developers to enterprise teams; Developer plan includes one seat |
Onboarding time | Streamlined setup; duration not specified |
Required skills | LLM and agent evaluation, dataset preparation, programming for custom code evaluators and SDK integration; no-code agent building is also available |
AEP branch | Agent Infrastructure |
AEP category | Harness |
AEP subcategory | Evaluation |
AEP detail | Agent-output Evals |
Profile
Agent-output Evals is the most specific AEP level for LangSmith. LangSmith is a platform for observing, evaluating, and deploying agents, with tools for building agents without code.
Its evaluation SDK supports batch evaluation results, allowing an evaluator to return multiple metrics at once. The platform also offers sign-up data region choices for the US, EU, and APAC; the selected region cannot be changed later.
Focus
LangSmith is for individual developers and enterprise teams working with AI agents and LLM applications. It addresses the work of evaluating, debugging, and monitoring those applications, and supports agent building and deployment.
Background
LangSmith is built by LangChain, the company behind LangChain and LangGraph. The supplied research does not identify LangChain’s founding or funding details. The LangSmith SDK has a public GitHub repository; the supplied research does not establish further open-source contribution details.
Features
Agent evaluation
Evaluate agent and LLM application outputs to assess their results. LangSmith provides evaluators, and its SDK documentation describes batch evaluation results that let an evaluator return multiple metrics at once.
Observation and monitoring
Observe agents and LLM applications to support ongoing monitoring. The platform presents observation and evaluation as core parts of its agent engineering offering.
Agent deployment
Deploy agents from the platform, extending its role beyond evaluation. LangSmith presents agent observation, evaluation, and deployment together.
No-code agent building
Build agents without code, providing an agent-building option alongside SDK and API access. The platform identifies no-code agent building as a supported capability.
Trace allowances by plan
Plan trace volume against the stated monthly allowances. The Developer tier includes up to 5,000 base traces per month and one seat; Plus includes 50,000 traces.
Pros and cons
Pros
Combines agent evaluation with observation, debugging, monitoring, and deployment in one platform.
Supports no-code agent building as well as API and SDK access.
Batch evaluation results can return multiple metrics from an evaluator at once.
The Developer tier is free and includes one seat and up to 5,000 base traces per month.
Cons
The selected data region—US, EU, or APAC—cannot be changed later, according to the sign-up flow.
Custom code evaluators and SDK integration require programming skills, and evaluation work also involves dataset preparation.
The Developer tier includes one seat and up to 5,000 base traces per month; Plus is listed at $39 per seat per month plus usage, so larger trace volumes or teams may require a paid plan.
FAQs
LangSmith FAQs
How does LangSmith work?
LangSmith evaluates agent and LLM application outputs using evaluators and supports debugging and monitoring; its evaluation SDK can return multiple metrics in a batch result.
Which integrations does LangSmith support?
LangSmith supports integrations with LangChain, LangGraph, BMC HelixGPT.
How much does LangSmith cost?
LangSmith's pricing model is Free Developer tier; Plus at $39 per seat per month plus usage; custom enterprise pricing.
What skills are needed to use LangSmith?
LangSmith's required skills are LLM and agent evaluation, dataset preparation, programming for custom code evaluators and SDK integration; no-code agent building is also available.
Can LangSmith's data region be changed after signup?
LangSmith's selected data region—US, EU, or APAC—cannot be changed later.
