LLMOps and observability
LangSmith: review, pricing, data and alternatives
LangSmith examines agent steps and compares results across versions. It serves people who want to create test datasets and monitor the costs and response times of their agents. A free tier exists; the first paid plan costs $39 per month. Access and transparency score: 85/100, #2 of 18 in its category.
What is LangSmith?
LangSmith examines agent steps and compares results across versions. It serves people who want to create test datasets and monitor the costs and response times of their agents.
According to its documentation, LangSmith lets you:
- examine the steps followed by an agent
- compare results from multiple versions
- create test datasets
- monitor costs and response times
We file it under LLMOps and observability, the category of tools to evaluate, monitor and debug AI apps, and it also overlaps with aI agent builders. The category lists 18 verified tools on this site.
The publisher is LangChain Inc., based in United States. The service launched in 2023, which gives it some track record.
Who is it for?
It is mostly useful to these profiles: developers and data analysts. The need it covers is simple to state: evaluate, monitor and debug AI apps.
LangSmith is a good candidate if:
- you want to try before paying
- you plan to connect it to your tools or automations through its API
Before deciding, run a trial on a real task and measure the time saved: it is the only criterion that really counts.
How much does LangSmith cost?
Pricing model: freemium (limited free use, then paid). A free plan is offered, usually limited in volume or features.
The first paid plan costs $39 per month (Plus, per user, excluding additional usage), according to the pricing page, checked on October 24, 2026.
Per month, that is cheaper than the category median ($49 per month, based on tools with a published price).
To estimate what the same work would cost done directly with an AI model, use our API price calculator. Prices change often: always check the official site before subscribing.
Data and privacy
According to its privacy policy, data is processed in several regions depending on the plan.
Exporting your content: yes (details on the official site). Being able to get your data back makes switching tools easier later.
Three habits apply to every AI tool:
- turn off the use of your content for training if the option exists
- use a work account separate from your personal account
- review everything the tool produces before publishing or sending it
Platforms, languages and API
LangSmith runs on: web browser and API.
Interface languages are not specified.
A public API lets you call it from your own programs or an automation tool, and plug it into an AI agent.
How we scored it
Our 85/100 score does not judge output quality: it measures what can be publicly verified about access to the tool, its openness and how far the publisher can be trusted.
| Criterion | Points | What counts |
|---|---|---|
| Access | 25/30 | free tier, published price, French interface |
| Openness | 20/30 | API, data export, open code |
| Trust | 40/40 | identified publisher, declared hosting, age, presence in reference lists |
The full calculation is explained on our method page.
Comparison with alternatives
LangSmith against other tools in the lLMOps and observability category:
| Tool | Free | Entry price | API | Score |
|---|---|---|---|---|
| LangSmith | Yes | $39 per month | Yes | 85 |
| Langfuse | Yes | $29 per month | Yes | 95 |
| Opik | Yes | $19 per month | Yes | 83 |
| Arize Phoenix | Yes | not published | Yes | 81 |
| Overmind | Yes | $120 per month | Yes | 78 |
| MLflow | Yes | not published | Yes | 78 |
| Respan | Yes | $199 per month | Yes | 71 |
| Prisma AIRS AI Gateway — Portkey | Yes | $49 per month | Yes | 71 |
Verdict
LangSmith is among the most accessible and transparent tools in its category.
Strengths
- Free tier to try it
- Cheaper than its category median
- Public API
- Established since 2023
Alternatives
Categories and jobs
Learn more
Frequently asked questions
Is LangSmith free?
Yes, a free plan exists, with usage limits. The first paid plan costs $39 per month.
Where is LangSmith data stored?
According to the publisher, in several regions depending on the plan.
Does LangSmith have an API?
Yes, a public API is documented.
What are the alternatives to LangSmith?
In the same category: Langfuse, Opik, Arize Phoenix, and Overmind.
LangSmith or Langfuse: which one to choose?
LangSmith starts at $39 per month, Langfuse at $29 per month and our score is 85/100 for LangSmith and 95/100 for Langfuse. Try both on the same task before paying.
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Neutrality. No affiliate links. No vendor pays to be reviewed, rated or ranked. Reviews are directed by François Chollet, neutral and factual, and every data point is dated and sourced. How we score