New
New
Stop Vibe-Checking Your AI.
Trace every decision.
Ship AI with confidence.
Trace every decision.
Ship AI with confidence.
Trace every decision.
Ship AI with confidence.
LangSmith gives teams X-ray vision into AI agents, so you can see how decisions are made, evaluate logic with humans in the loop, and deploy AI systems you actually trust.
LangSmith gives teams X-ray vision into AI agents, so you can see how decisions are made, evaluate logic with humans in the loop, and deploy AI systems you actually trust.
LangSmith gives teams X-ray vision into AI agents, so you can see how decisions are made, evaluate logic with humans in the loop, and deploy AI systems you actually trust.
Start Tracing for Free
Start Tracing for Free
Start Tracing for Free
Watch a Real Trace →
Watch a Real Trace →
Watch a Real Trace →
The Problem: "The Black Box"
The Problem: "The Black Box"
The Problem: "The Black Box"
AI is Non-Deterministic.
Your Debugging Shouldn’t Be.
AI is Non-Deterministic.
Your Debugging Shouldn’t Be.
AI is Non-Deterministic.
Your Debugging Shouldn’t Be.
Modern AI agents don’t follow linear logic. They reason probabilistically, change behavior over time, and fail silently. When something breaks, most teams don’t investigate. They guess. That’s not engineering. That’s vibe-checking.
Modern AI agents don’t follow linear logic. They reason probabilistically, change behavior over time, and fail silently. When something breaks, most teams don’t investigate. They guess. That’s not engineering. That’s vibe-checking.
Modern AI agents don’t follow linear logic. They reason probabilistically, change behavior over time, and fail silently. When something breaks, most teams don’t investigate. They guess. That’s not engineering. That’s vibe-checking.
"It worked yesterday."
Your AI agent hasn’t changed but its context has. A different user phrasing, a new document in the knowledge base, or a subtle model update can quietly alter behavior. Without tracing, teams are left debugging time, not logic.
"The prompt looks fine?"
Prompts rarely fail in isolation. Failures emerge from the interaction between prompts, retrieval, memory, and tools. Reading the prompt tells you what you asked, not why the AI answered the way it did.
"Let's rollback & hope."
Rolling back isn’t fixing the problem, it’s avoiding understanding it.
Teams trade progress for stability, shipping slower out of fear.
Hope becomes the safety mechanism when visibility is missing.
Rolling back isn’t fixing the problem, it’s avoiding understanding it.
Teams trade progress for stability, shipping slower out of fear.
Hope becomes the safety mechanism when visibility is missing.
Rolling back isn’t fixing the problem, it’s avoiding understanding it.
Teams trade progress for stability, shipping slower out of fear.
Hope becomes the safety mechanism when visibility is missing.
The Solution: X-Ray Vision for AI
The Solution: X-Ray Vision for AI
The Solution: X-Ray Vision for AI
See What Your AI Is Thinking.
Not Just What It Says.
See What Your AI Is Thinking.
Not Just What It Says.
See What Your AI Is Thinking.
Not Just What It Says.
LangSmith instruments AI at the reasoning layer, the place where decisions are actually made.
Instead of treating your agent as a black box that magically turns inputs into outputs, LangSmith exposes the full decision chain in between.
You can see how context was interpreted, which information was retrieved, what tools were called, and why a final answer was chosen. This is observability for intelligence, not infrastructure.
What You Can Trace
What You Can Trace
What You Can Trace
Every decision path
See the exact reasoning branches your agent explored, including alternatives it considered and discarded. When behavior changes, you can pinpoint which decision changed and why.
Every tool call
Understand when your agent invoked external tools, APIs, or actions, what parameters it passed, and how those responses influenced the final outcome.
Every retrieval step
Inspect which documents, memory entries, or knowledge base chunks were retrieved, ranked, and used. No more guessing whether the right context was actually seen.
Every decision path
See the exact reasoning branches your agent explored, including alternatives it considered and discarded. When behavior changes, you can pinpoint which decision changed and why.
Every tool call
Understand when your agent invoked external tools, APIs, or actions, what parameters it passed, and how those responses influenced the final outcome.
Every retrieval step
Inspect which documents, memory entries, or knowledge base chunks were retrieved, ranked, and used. No more guessing whether the right context was actually seen.
Every decision path
See the exact reasoning branches your agent explored, including alternatives it considered and discarded. When behavior changes, you can pinpoint which decision changed and why.
Every tool call
Understand when your agent invoked external tools, APIs, or actions, what parameters it passed, and how those responses influenced the final outcome.
Every retrieval step
Inspect which documents, memory entries, or knowledge base chunks were retrieved, ranked, and used. No more guessing whether the right context was actually seen.
What Trust Looks Like in Production
Designed for the AI Era
What Trust Looks Like in Production
Designed for the AI Era
What Trust Looks Like in Production
Designed for the AI Era
Logic Tracing
Logic Tracing
Trace intelligence step by step.
Step-by-step decision trees
Searchable, replayable traces
Built for real-world debugging
Human-in-the-Loop Evaluation
Define “good” with human judgment.
Annotate reasoning, not just output
Capture edge cases
Train against real expectations
Production-Grade Observability
Built for systems that ship.
Behavior change detection
Model, prompt, & tool comparisons
Confidence to ship fast without fear
Testimonials
Testimonials
Testimonials
Trusted in Production.
Proof, Not Promises.
Trusted in Production.
Proof, Not Promises.
Trusted in Production.
Proof, Not Promises.
Real businesses, real results with LangSmith.
Real businesses, real results with LangSmith.
Real businesses, real results with LangSmith.
Before LangSmith, we knew when our AI failed but not why. Now we can trace every decision our agent makes and ship changes with confidence instead of fear.
James Carter
Before LangSmith, we knew when our AI failed but not why. Now we can trace every decision our agent makes and ship changes with confidence instead of fear.
James Carter
Before LangSmith, we knew when our AI failed but not why. Now we can trace every decision our agent makes and ship changes with confidence instead of fear.
James Carter
LangSmith turned AI behavior into something we can reason about. We stopped arguing opinions and started reviewing traces. That shift alone changed how fast we ship.
Sophia Martinez
LangSmith turned AI behavior into something we can reason about. We stopped arguing opinions and started reviewing traces. That shift alone changed how fast we ship.
Sophia Martinez
LangSmith turned AI behavior into something we can reason about. We stopped arguing opinions and started reviewing traces. That shift alone changed how fast we ship.
Sophia Martinez
"This is the first time debugging AI feels like engineering instead of guesswork. Logic tracing and golden datasets give us real observability not just logs."
David Reynolds
"This is the first time debugging AI feels like engineering instead of guesswork. Logic tracing and golden datasets give us real observability not just logs."
David Reynolds
"This is the first time debugging AI feels like engineering instead of guesswork. Logic tracing and golden datasets give us real observability not just logs."
David Reynolds
Once we could see how the agent was thinking, escalations dropped and trust went up both internally and with customers. LangSmith paid for itself faster than we expected.
Emily Wong
Once we could see how the agent was thinking, escalations dropped and trust went up both internally and with customers. LangSmith paid for itself faster than we expected.
Emily Wong
Once we could see how the agent was thinking, escalations dropped and trust went up both internally and with customers. LangSmith paid for itself faster than we expected.
Emily Wong
Pricing
Pricing
Pricing
Production-Ready AI,
Priced for Reality
Choose a plan that fits your needs and scale confidently as your AI moves into production.
Choose a plan that fits your needs and scale confidently as your AI moves into production.
Choose a plan that fits your needs and scale confidently as your AI moves into production.
Monthly
Annually
Starter
Free
For teams experimenting with AI and early prototypes.
What's Included:
Trace Prompts & Responses
Basic Execution Logs
Limited Workflow Runs
Community Support
Up to 3 AI integrations
Professional
Popular
$200/year
For teams running AI in production who need visibility and control.
What's Included:
Full Logic & Chain-of-Thought Tracing
Tool Calls & Retrieval Inspection
Human-in-the-Loop Evaluations
Advanced Analytics & Debugging
Up to 10 AI Integrations
Enterprise
Custom
For organizations scaling mission-critical AI systems.
What's Included:
End-to-end Observability Across All Agents
Custom Evaluation Pipelines
Enterprise Security & Compliance
24/7 Priority Support
Unlimited Integrations
Monthly
Annually
Starter
Free
For teams experimenting with AI and early prototypes.
What's Included:
Trace Prompts & Responses
Basic Execution Logs
Limited Workflow Runs
Community Support
Up to 3 AI integrations
Professional
Popular
$200/year
For teams running AI in production who need visibility and control.
What's Included:
Full Logic & Chain-of-Thought Tracing
Tool Calls & Retrieval Inspection
Human-in-the-Loop Evaluations
Advanced Analytics & Debugging
Up to 10 AI Integrations
Enterprise
Custom
For organizations scaling mission-critical AI systems.
What's Included:
End-to-end Observability Across All Agents
Custom Evaluation Pipelines
Enterprise Security & Compliance
24/7 Priority Support
Unlimited Integrations
Monthly
Annually
Starter
Free
For teams experimenting with AI and early prototypes.
What's Included:
Trace Prompts & Responses
Basic Execution Logs
Limited Workflow Runs
Community Support
Up to 3 AI integrations
Professional
Popular
$200/year
For teams running AI in production who need visibility and control.
What's Included:
Full Logic & Chain-of-Thought Tracing
Tool Calls & Retrieval Inspection
Human-in-the-Loop Evaluations
Advanced Analytics & Debugging
Up to 10 AI Integrations
Enterprise
Custom
For organizations scaling mission-critical AI systems.
What's Included:
End-to-end Observability Across All Agents
Custom Evaluation Pipelines
Enterprise Security & Compliance
24/7 Priority Support
Unlimited Integrations
Let AI Work
With Complete Visibility
See every decision, trace every step, and fix failures before users notice.
See every decision, trace every step, and fix failures before users notice.
See every decision, trace every step, and fix failures before users notice.