Plausible Analytics
NeuralAgentPersonal AI Assistant That Operates Your Entire Computer“For monitoring AI Model performance.”
LLM Observability & EvalsMaker says so · source ↗
LangSmith
Observability and evaluation platform for LLM agents, with tracing, monitoring, and dataset-based testing; framework-agnostic but built by the LangChain team.
Works with AI agents:llms.txtAsk your AI about this, with this page as the source:ChatGPT ↗Claude ↗Perplexity ↗
LangSmith is LangChain's hosted platform for watching and testing LLM agents. It records each run of your app as a trace of nested steps (model calls, tools, retrieval) so you can see why an agent did what it did, then turns those runs into datasets and evaluations so you can check that a prompt or model change made things better rather than worse.
You instrument code with its SDKs for Python, TypeScript, Go or Java, typically by wrapping your LLM client or marking functions as traceable; LangChain and LangGraph apps switch it on with an environment variable. It also accepts OpenTelemetry traces on an OTLP endpoint, and the Vercel AI SDK has a dedicated integration. In JavaScript, runs are sent in the background by default so tracing doesn't add latency.
For a small team the useful parts are trace search with dashboards and alerts, online evaluators (LLM-as-a-judge) that score production traffic, offline experiments over datasets, and a prompt playground. The same account can also host agent deployments. The managed cloud runs in US, EU and APAC regions on GCP and a US region on AWS, and you pick the region at sign-up.
Traces are kept 14 days at base retention, with longer retention billed separately. Self-hosting is only available as an Enterprise add-on, and an organization can't move between regions after sign-up.
Where it fits
How LangSmith itself is built
1 tools, from its own code, website and Product Hunt page.
Who uses it
11 makers' products, each linked to the source that shows it, and 49 open-source projects that declare it in their code.
NeuralAgentPersonal AI Assistant That Operates Your Entire Computer
AstridThe personal stylist programmed just for you“We absolutely could not build this product with LangSmith for traces, datasets, annotation queues, and evals. We've become big power users! I use to build AI apps before nice tracing tools like this existed and it's like night and day having a tool like this. We considered Langfuse, but I already had experience with LangSmith so for speed purposes we went with LangSmith.”
LLM Observability & EvalsMaker says so · source ↗
GitLawAgent + templates + workflow. Making legal documents free.“Evals / tracing / monitoring is awesome and out of the box”
LLM Observability & EvalsMaker says so · source ↗“You can't build AI agents without monitoring. Metadata filtering is strong.”
LLM Observability & EvalsMaker says so · source ↗
IntrycAI scores tickets to your SOPs with 90% precision“Shoutout for all the observability and prompt management capabilities!”
LLM Observability & EvalsMaker says so · source ↗
PigAutomate Your Windows Computer with AI“I deployed the manage Pig agent on LangGraph and it's been smooth sailing!”
LLM Observability & EvalsMaker says so · source ↗
Watchman AICapturing invisible B2B buyers with AI agents“LangSmith’s real-time analytics and versioning keep our AI agents rock-solid -- so everything just works better.”
LLM Observability & EvalsMaker says so · source ↗
lmChatGPTtfyThe ChatGPT pendant of Let me Google that for you“Our preferred way to track and analyze tool usage. Really easy to handle.”
LLM Observability & EvalsMaker says so · source ↗
Meet-TingAI That Gives Your Schedule a Brain | Availability Agent“We started building Ting without LangSmith and we were flying blind. Diagnosing issues downstream felt like guesswork. Since bringing LangSmith in, we’ve been able to trace problems through the entire prompt path and actually understand what’s going on. We’re still evolving how we use it, but even early on it’s helped us move faster and get closer to that “this feels good” moment.”
LLM Observability & EvalsMaker says so · source ↗“Promptius <3 Langchain + Langgraph + Langsmith, this combination has been instrumental in building Promptius in the past 5 months! The abstractions provided by Langchain and Langgraph make building agents as easy as writing a prose. Langsmith provides unmatched observability and also help track our costs.”
LLM Observability & EvalsMaker says so · source ↗
CrewAIPython framework for orchestrating role-based teams of autonomous AI agents (Crews) plus…LLM Observability & EvalsIn its code · source ↗
FirecrawlWeb scraping and crawling API that turns websites into clean markdown or structured JSON…LLM Observability & EvalsIn its code · source ↗
MastraTypeScript framework for building AI agents, workflows, and RAG applications with memory…LLM Observability & EvalsIn its code · source ↗Open source: a project that declares LangSmith as a dependency in its public code — verifiable, but not necessarily a live product.
What makers say
8 makers on why they use LangSmith, in their own words on Product Hunt.
We absolutely could not build this product with LangSmith for traces, datasets, annotation queues, and evals. We've become big power users! I use to build AI apps before nice tracing tools like this existed and it's like night and day having a tool like this. We considered Langfuse, but I already had experience with LangSmith so for speed purposes we went with LangSmith.
AstridSep 2026 ↗LangSmith’s real-time analytics and versioning keep our AI agents rock-solid -- so everything just works better.
Watchman AISep 2026 ↗You can't build AI agents without monitoring. Metadata filtering is strong.
I deployed the manage Pig agent on LangGraph and it's been smooth sailing!
PigSep 2026 ↗Our preferred way to track and analyze tool usage. Really easy to handle.
lmChatGPTtfySep 2026 ↗Loved and watch-outs
Themes that recur in makers' words and Hacker News comments, each linked to what it summarises, with how Product Hunt tags its reviews.
Most loved
Watch-outs
- It keeps pulling users toward the LangChain platform, and LangChain docs push LangSmith, which feels like lock-in. HNHN 2HN 3HN 4
- Traces show which agent failed but not why, so root-cause analysis stays manual. HNHN 2HN 3HN 4
- Viewing your own traces requires a cloud account, with no local-first option. HNHN 2
- The prompt engineering workflow is laborious, gets expensive fast and handles multi-turn prompts poorly. HNHN 2
On Product Hunt 4.8★ · 19 reviews
monitoring AI model performance 3chain sequence debugging 2evals 2
Read the reviews on Product Hunt ↗Reliability and open issues
Incidents on its status page0 in the last 90 days · 0 in the last yearFrom its own status page, 2026-10-02. Vendors decide what they post; one page can cover several products.
Who switches
Public pull requests on GitHub since Oct 2024 whose title says "X to Y" — real code changes moving a project from one tool to another, by developers in general. Open a row to see the pull requests.
LangSmith → Langfuse9 PRs
- Migrate observability from LangSmith to Langfuse and trim logged fieldsHOSH19/HarnessLab · 2026-08-29
- feat: migrate observability from LangSmith to Langfuse Cloud (v4 SDK)icekarim/momo-assistant · 2026-08-05
- feat(trace): migrate LangSmith to Langfuse v4 and fix env key priority1935494577/Xiaoxin-Agentic-RAG-System · 2026-08-01
- [codex] Migrate from LangSmith to Langfuse, remove Python legacy, fix review issuesBunnyRabbit8mile/codex-tee · 2026-07-14
- Reapply "feat: migrate observability from LangSmith to Langfuse"sinuarlowbaby/RAG-PDF-Chatbot · 2026-07-14
- refactor: migrate observability from LangSmith to Langfusewei-yiting/fin-lab-x · 2026-03-18
- Migrate observability from LangSmith to LangfuseAneeshPulukkul/hybrid-rag-solution · 2026-03-14
- feat:migrate LLM observabilty from LangSmith to LangFuse100-hours-a-week/17-JinyUs-Q-Feed-AI · 2026-02-26
- Refactor: Migrate from Langsmith to Langfusedylangamachefl/fantasy-football-chatbot-v2 · 2025-12-01
Alternatives to LangSmith
All alternatives by situation →LangfuseTracing, prompt management and evals in one tool you can run on your own server for free.Compare with LangSmith →
BraintrustEval-driven work — scoring outputs and comparing prompts and models side by side in experiments.Compare with LangSmith →
MLflowTracing, evaluating and versioning prompts for LLM apps in the same open-source platform many teams already use for ML experiments.Compare with LangSmith →
RagasScoring RAG pipelines — how faithful answers are to the retrieved context and how relevant that context is — and generating test questions from your documents.Compare with LangSmith →
Arize PhoenixOpenTelemetry-based tracing and evals you can start locally in a notebook, then self-host or move to its cloud.Compare with LangSmith →
Helicone
Opik
Promptfoo
DeepEvalQuestions makers ask about LangSmith
Do I have to use LangChain to use it?
No. The SDKs trace any code and are documented as usable without LangChain; LangChain and LangGraph apps only get a shortcut, enabling tracing with a single environment variable. source ↗
Can I keep my data in the EU?
Yes. LangSmith has an EU instance in the Netherlands (GCP europe-west4), plus US and APAC instances, available on every plan including the free one. Billing data stays in the US, and you can't switch an organization between regions later. source ↗
Is it SOC 2 and HIPAA compliant?
LangChain states LangSmith is SOC 2 Type 2 certified, HIPAA compliant and GDPR compliant, and offers a DPA through support. It has no EU legal entity for contracting. source ↗
Can I send OpenTelemetry traces instead of using its SDK?
Yes. LangSmith accepts OTLP traces at its /otel endpoint, and you can use an OpenTelemetry Collector to send the same spans to LangSmith and another backend such as Datadog or Grafana. source ↗
Will tracing slow down my serverless functions?
The JS SDK sends traces in the background by default. In serverless runtimes you either turn background tracing off or await pending trace batches before the function returns, so data isn't lost when the runtime freezes. source ↗
How long are traces kept?
Base traces are kept 14 days and extended traces 180 days. Some actions, like online evaluators and automation rules, can upgrade a trace to extended retention; after retention ends, trace inputs and outputs are deleted. source ↗
Can I self-host it?
Only as an add-on to the Enterprise plan, installed on Kubernetes with a license key from LangChain's sales team. source ↗
Is LangSmith free?
Yes — there is a free tier a small product can run on; paid use starts at $39/seat/mo. source ↗
Is LangSmith open source or self-hostable?
Not open source, and hosted only.
Can AI coding agents work with LangSmith?
It serves an llms.txt docs index.
Who uses LangSmith?
11 makers' products we track, each with a source, and 49 open-source projects declare it in their code. source ↗