LangSmith

LangChain provides the agent engineering platform and open source frameworks developers need to ship reliable agents fast.

Agent Operations

Visit Website

Founded

2022

Location

San Francisco, CA

Employees

150

Funding

Backed by LangChain

LangSmith (by LangChain)

**Production platform for AI agents** that unifies observability, evaluation, and deployment—so teams can trace, test, and ship reliable agentic applications faster. LangSmith is framework‑agnostic and supports OpenTelemetry, enabling cross‑service, multi‑stack tracing beyond LangChain/LangGraph.

Visit: [LangSmith](https://smith.langchain.com)

Docs: [LangSmith Documentation](https://docs.langchain.com/langsmith)

Pricing: [LangChain Pricing](https://www.langchain.com/pricing)

What LangSmith Does

**Deep observability:** Step‑level traces of prompts, tool calls, and reasoning; cost/latency dashboards; custom alerts; OpenTelemetry support.

**Rigorous evaluation:** Online/offline and multi‑turn agent evals; human feedback queues; prompt/version testing.

**Operational tooling:** Long‑running agent deployments with streaming, scheduling, RBAC, and horizontal scaling.

**Flexible deployment:** Host in US or EU regions, hybrid, or fully self‑hosted for stricter data controls.

Why Teams Choose LangSmith

**Debug faster:** Rich run traces, visual Studio for pinpointing failures, and versioned prompt experiments accelerate iteration.

**Prove quality:** Built‑in eval workflows and human-in-the-loop feedback to measure and improve agent reliability.

**Operate at scale:** Production‑grade deployment, monitoring, and access controls for complex, long‑running agents.

**Stay compliant:** Data residency options and self‑hosting paths for regulated environments.

Who It’s For

**AI platform and infra teams** standardizing tracing, evals, and monitoring across services.

**Product teams** shipping AI agent features that need reliable, measurable behavior.

**Data/ML engineers** instrumenting agents with unified telemetry and performance insights.

Common Use Cases

Trace tool usage and chain-of-thought steps (where applicable), with **cost/latency/SLA monitoring**.

Run **multi‑turn evaluations** and manage **prompt versions** across experiments.

Collect **user feedback** and cluster conversations with Insights to prioritize improvements.

Unify traces across microservices via **OpenTelemetry** for end‑to‑end visibility.

Integrations

**SDKs:** Python and JS/TS.

**APIs:** Works with the **Assistants API** and popular model providers, vector databases, and data tools.

**Telemetry:** Native **OpenTelemetry (OTel)** for cross‑service trace correlation.

Pricing

**Developer:** Free.

**Plus:** $39/seat/month (includes one developer deployment; base/extended trace retention tiers).

**Enterprise:** Custom.

Try it free—no credit card. See details: [Pricing](https://www.langchain.com/pricing)

Data Residency & Deployment Options

**US or EU hosting**, hybrid deployment, or **fully self‑hosted** for stricter compliance needs.

Buyer Notes (From User Sentiment)

**Strengths:** Best‑in‑class debugging and evaluation; enables fast iteration cycles.

**Considerations:** UI changes can be frequent; confirm EU data residency requirements if applicable.

Get Started

Create an account: [LangSmith](https://smith.langchain.com)

Explore the platform: [LangSmith Docs](https://docs.langchain.com/langsmith)

Meta description: LangSmith by LangChain is a production platform for AI agents that combines observability, multi‑turn evaluation, and deployment. Framework‑agnostic with OpenTelemetry support, it helps teams trace, test, and ship reliable agentic apps at scale with flexible hosting and enterprise controls.

Related Companies

Galileo

Galileo is the leading platform for enterprise GenAI evaluation and observability. Our comprehensive suite of products support builders across the new AI development workflow—from fine-tuning LLMs to developing, testing, monitoring, and securing their AI applications. Each product is powered by our research-backed evaluation metrics. Today, Galileo is used by 100s of AI teams from startups to Fortune 50 enterprises, including Twilio, Comcast, and HP.

HoneyHive

HoneyHive is the leading AI observability and evals platform, trusted by next-gen AI startups to Fortune 100 enterprises. We make it easy and repeatable for modern AI teams to debug, evaluate, and monitor AI agents, and deploy them to production with confidence. HoneyHive’s founding team brings AI and infrastructure expertise from Microsoft OpenAI, Amazon, Amplitude, New Relic, and Sisu. The company is based in New York and San Francisco.

Humanloop

Humanloop is the LLM evals platform for enterprises. Teams at Gusto, Vanta and Duolingo use Humanloop to ship reliable AI products. We enable you to adopt best practices for prompt management, evaluation and observability.

LangFuse

Langfuse is the 𝗺𝗼𝘀𝘁 𝗽𝗼𝗽𝘂𝗹𝗮𝗿 𝗼𝗽𝗲𝗻 𝘀𝗼𝘂𝗿𝗰𝗲 𝗟𝗟𝗠𝗢𝗽𝘀 𝗽𝗹𝗮𝘁𝗳𝗼𝗿𝗺. It helps teams collaboratively develop, monitor, evaluate, and debug AI applications. Langfuse can be 𝘀𝗲𝗹𝗳-𝗵𝗼𝘀𝘁𝗲𝗱 in minutes and is battle-tested and used in production by thousands of users from YC startups to large companies like Khan Academy or Twilio. Langfuse builds on a proven track record of reliability and performance. Developers can trace any Large Language model or framework using our SDKs for Python and JS/TS, our open API or our native integrations (OpenAI, Langchain, Llama-Index, Vercel AI SDK). Beyond tracing, developers use 𝗟𝗮𝗻𝗴𝗳𝘂𝘀𝗲 𝗣𝗿𝗼𝗺𝗽𝘁 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁, 𝗶𝘁𝘀 𝗼𝗽𝗲𝗻 𝗔𝗣𝗜𝘀, 𝗮𝗻𝗱 𝘁𝗲𝘀𝘁𝗶𝗻𝗴 𝗮𝗻𝗱 𝗲𝘃𝗮𝗹𝘂𝗮𝘁𝗶𝗼𝗻 𝗽𝗶𝗽𝗲𝗹𝗶𝗻𝗲𝘀 to improve the quality of their applications. Product managers can 𝗮𝗻𝗮𝗹𝘆𝘇𝗲, 𝗲𝘃𝗮𝗹𝘂𝗮𝘁𝗲, 𝗮𝗻𝗱 𝗱𝗲𝗯𝘂𝗴 𝗔𝗜 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝘀 by accessing detailed metrics on costs, latencies, and user feedback in the Langfuse Dashboard. They can bring 𝗵𝘂𝗺𝗮𝗻𝘀 𝗶𝗻 𝘁𝗵𝗲 𝗹𝗼𝗼𝗽 by setting up annotation workflows for human labelers to score their application. Langfuse can also be used to 𝗺𝗼𝗻𝗶𝘁𝗼𝗿 𝘀𝗲𝗰𝘂𝗿𝗶𝘁𝘆 𝗿𝗶𝘀𝗸𝘀 through security framework and evaluation pipelines. Langfuse enables 𝗻𝗼𝗻-𝘁𝗲𝗰𝗵𝗻𝗶𝗰𝗮𝗹 𝘁𝗲𝗮𝗺 𝗺𝗲𝗺𝗯𝗲𝗿𝘀 to iterate on prompts and model configurations directly within the Langfuse UI or use the Langfuse Playground for fast prompt testing. Langfuse is 𝗼𝗽𝗲𝗻 𝘀𝗼𝘂𝗿𝗰𝗲 and we are proud to have a fantastic community on Github and Discord that provides help and feedback. Do get in touch with us!

Phoenix (Arize AI)

Ship Agents that Work. Arize AI & Agent Engineering Platform. One place for development, observability, and evaluation.

Portkey

AI Gateway, Guardrails, and Governance. Processing 14 Billion+ LLM tokens every day. Backed by Lightspeed.