What is LangSmith?

LangSmith is LangChain's commercial platform for building and running AI agents. It covers observability, evaluation, prompt management, and deployment, and its tracing works natively with LangChain and LangGraph and with other frameworks through SDKs for Python, TypeScript, Go, and Java plus OpenTelemetry. Teams already on LangChain get trace structure for every chain, tool, and agent step without adding instrumentation.

Pricing combines seats and traces. The free Developer plan is limited to one seat, and each Plus seat costs $39 a month, so the bill grows with team size as well as traffic. Base traces are kept for 14 days, and keeping a trace longer moves it to a pricier extended tier. Self-hosting and hybrid deployment are only available on Enterprise.

LangSmith also added an LLM Gateway, currently in beta, for multi-provider access, fallbacks, and spend limits. If per-seat pricing or a gateway still in beta is a sticking point, the LangSmith alternatives worth comparing include platforms that ship a production gateway alongside tracing and evals.

Key features

Core capabilities this platform advertises.

Native tracing for LangChain and LangGraph
OpenTelemetry and multi-language SDKs
Offline and online evaluations
Annotation queues and datasets
Prompt Hub with versioning

Strengths and tradeoffs

What this tool does well, and the limitations to keep in mind.

Pros

Native LangChain and LangGraph tracing with no extra instrumentation
Evals, datasets, and annotation queues sit in the same workspace as traces
Tracing, deployment, and sandboxes from one vendor
Framework-agnostic SDKs and OpenTelemetry support

Cons

Per-seat pricing on Plus, and the free plan allows one seat
14-day base retention, with longer retention billed at a higher rate
LLM Gateway is still in beta
Self-hosting and hybrid deployment are Enterprise only

Plans & pricing

What's included in each plan, and how the tiers compare.

Developer

Free

Up to 5,000 base traces/mo, then pay-as-you-go
14-day base retention
One seat
Basic evaluations

Plus

$39

Per seat/month

Up to 10,000 base traces/mo, then $2.50 per 1k
Unlimited seats
180-day extended retention ($5 per 1k traces)
1 free serverless deployment

Enterprise

Custom

Contact sales for a quote

Cloud, hybrid, or self-hosted
Custom SSO, RBAC, and ABAC
Custom seats and workspaces

View official pricing page

Common use cases

Teams building agents on LangChain or LangGraph who want tracing, evals, and deployment from one vendor

Debugging LangChain and LangGraph agents
Evaluating agent output against datasets
Human review through annotation queues
Deploying long-running agents

Using LangSmith with Respan

Teams building on LangChain or LangGraph can trace with Respan through respan-instrumentation-langchain, which captures every chain, model, tool, retriever, and agent run. Point model calls at the Respan gateway too, and each request is routed across 1,000+ models, traced, and scored on the same record.

Trace LangChain and LangGraph runs with one instrumentor
Route model calls across 1,000+ models through one OpenAI-compatible endpoint
Score output on live production traffic with automated evals
Unlimited seats on the free plan, with no per-seat pricing

Trace, route, and score your LangChain agents

10KFree traces/mo

1,000+Models

5 minSetup

Respan traces every LangChain and LangGraph run, routes each model call across 1,000+ models, and scores output on live traffic, with unlimited seats on the free plan. Start free.

Try Respan free

Best LangSmith alternatives & competitors

Top companies in Observability, Prompts & Evals you can use instead of LangSmith.

Respan

Nested traces for every LLM call, tool run, and agent turn

LangSmith: Pricing, Features, Pros & Cons