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Free plan + paidInformation reviewed 2026-10-09

LangSmith

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About this listing

Official documentation reviewed; examples are illustrative. No hands-on performance claim.

Official source

LangSmith helps developers inspect LLM runs and evaluate application behaviour.

Best suited to

Tracing and evaluating LLM applications

Meet LangSmith

What LangSmith helps you do

LangSmith helps developers inspect LLM runs and evaluate application behaviour. Use traces and a small labelled dataset to find whether a failure comes from retrieval, prompting or a tool call.

Best for: Tracing and evaluating LLM applications.

A small task to try

  1. Instrument a test application rather than a production conversation
  2. Create five synthetic questions with known expected answers
  3. Run the current prompt and inspect a failed trace
  4. Compare a revised prompt on the same dataset

Illustrative input: Evaluate a FAQ bot against five questions, including one that has no answer in the source.

Illustrative expected result: A run-by-run comparison showing source-grounded answers and an explicit unknown response. This is an editorial example, not a recorded vendor test. Check it against your original material before using it.

Access and buying guidance

Developer is USD 0 with one seat and 5,000 base traces/month; extra usage is metered. Plus and deployment options add costs. Check retention and trace types on the pricing page.

Useful evaluation requires labelled examples and clear success criteria. Start with the smallest useful task; keep the original input and compare the result before committing to a larger workflow.

Alternatives for a different workflow

Dify: inspect runs in an application builder. Langflow: prototype the flow before instrumenting it.

Sources and review

Reviewed 9 October 2026 against official product documentation and official pricing / access terms. Feature access and prices can change; the linked provider terms govern your account.

Illustrative workspace photo
Illustrative stock photo from Unsplash; not a screenshot of LangSmith.

What you can do

Application tracing

LLM evaluations

Datasets

Prompt iteration

Run inspection

Usage monitoring

Agent deployment options

Where it helps

  • Trace inspection makes multi-step failures easier to locate
  • A saved dataset gives prompt changes a repeatable comparison
  • Evaluation separates a convincing answer from one that passes your task criteria

What to consider

  • Useful evaluation requires labelled examples and clear success criteria
  • Trace allowances, deployment compute and model API costs are separate

Pricing & free access

Official pricing
Free plan + paid

Developer is USD 0 with one seat and 5,000 base traces/month; extra usage is metered. Plus and deployment options add costs. Check retention and trace types on the pricing page.

Plan information can change. Prices and conditions are set by the provider. Information checked 2026-10-09.

Source for access details

Get free-plan changes by email

One email a week: new free AI tools, prompts and free-plan changes. No spam, unsubscribe any time.

Questions about LangSmith

What is LangSmith best used for?

LangSmith helps developers inspect LLM runs and evaluate application behaviour. Use traces and a small labelled dataset to find whether a failure comes from retrieval, prompting or a tool call.

Is LangSmith free to use?

Developer is USD 0 with one seat and 5,000 base traces/month; extra usage is metered. Plus and deployment options add costs. Check retention and trace types on the pricing page.

How can I try LangSmith on a small task?

Instrument a test application rather than a production conversation Create five synthetic questions with known expected answers Run the current prompt and inspect a failed trace Compare a revised prompt on the same dataset

What should I check before relying on LangSmith?

Useful evaluation requires labelled examples and clear success criteria Trace allowances, deployment compute and model API costs are separate

Which alternatives should I compare with LangSmith?

Dify: inspect runs in an application builder. Langflow: prototype the flow before instrumenting it.

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Review evidence

Documentation-based review · 2026-10-09

Original editorial guidance based on linked official sources; sample inputs and outputs are illustrative.

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