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LangWatch

Q: How much does LangWatch cost?

Open source under Apache 2.0, free to self host. Free cloud tier includes 200,000 events a month. Paid cloud is about 29 euro per seat with unlimited lite seats for sharing results, plus usage at one dollar per 100,000 additional events. On premise and hybrid options for data residency.

Q: Who is LangWatch for?

developers, AI engineering teams, product teams

Also known as: Langwatch

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Agent infrastructureindependentVerified 2026-07-06

Open source platform for agent observability, evaluation, and scenario based simulation, with OpenTelemetry tracing and a built in AI gateway.

LangWatch is an open source platform, licensed under Apache 2.0, for observing, evaluating, and testing large language model powered agents. It combines production observability, continuous evaluation, and scenario based simulation in one loop, trace to dataset to evaluate to optimize to re test, so teams can understand agent behavior across real workflows and systematically improve reliability, performance, and cost. Tracing is OpenTelemetry native and framework and provider agnostic, with integrations for LangChain, LangGraph, CrewAI, the Vercel AI SDK, Mastra, and Google ADK, and support for using LangWatch through MCP clients such as Claude Desktop.

A distinguishing feature is agent simulation. LangWatch can run multi turn conversations against an agent in parallel, score them with a judge rubric on measures like faithfulness and policy adherence, and turn failures into pull requests, letting product managers own the specification while developers stay in flow. Domain experts can review runs, annotate failures, and label edge cases through annotation queues, and prompts live in Git through a GitHub integration with prompt versions linked to traces.

LangWatch also ships an AI Gateway, an OpenAI and Anthropic compatible proxy with virtual keys, hierarchical budgets, inline guardrails, and automatic fallback across providers, adding governance and cost control with roughly seven hundred nanoseconds of hot path overhead. The full platform is open source and self hosts through Docker or a Helm chart on Kubernetes, with cloud specific setups for AWS, Google Cloud, and Azure and hybrid options for teams with data residency requirements. Pricing keeps a free tier with two hundred thousand events a month, charges around twenty nine euro per seat with unlimited lite seats for sharing results, and bills additional usage at one dollar per one hundred thousand events, with the open source build free to self host.

Vendor details

Canonical URL

https://langwatch.ai

Subcategory

Observability and evaluation

Funding status

Independent. Open source under Apache 2.0 with an active project used by thousands of AI developers. Offers a managed cloud alongside self hosted, on premise, and hybrid deployment.

Company status

independent

Use cases & customers

Primary use cases

agent observabilityevaluation and scenario testingprompt managementgateway governance and cost control

Target customers

developersAI engineering teamsproduct teams

Deployment options

SaaSself-hostedon-premVPC

Integrations

OpenTelemetry native and framework and provider agnostic, with integrations for LangChain, LangGraph, CrewAI, the Vercel AI SDK, Mastra, and Google ADK. Usable through MCP clients like Claude Desktop, with a GitHub integration for prompt versioning and an OpenAI and Anthropic compatible gateway reaching hundreds of models.

In practice

Your agent passes eyeball checks but breaks in production. LangWatch runs multi turn simulations against it in parallel, scores them with a judge rubric, and turns failures into pull requests before launch.

A product manager needs to test agent behavior without code. They write the goal in plain English, LangWatch generates the scenario plan and rubric, and developers stay in flow while nothing slips through.

You want tracing plus cost control in one place. LangWatch gives OpenTelemetry native traces and an OpenAI and Anthropic compatible gateway with virtual keys, budgets, and provider fallback, self hosted if needed.

Sources & related URLs

Research sources

https://langwatch.ai https://github.com/langwatch/langwatch https://langwatch.ai/llm-observability

Capability coverage

6.5 / 14 capabilities · 46%

Integrations & Tool CallingOpenTelemetry native, framework agnostic, integrations for LangChain, LangGraph, CrewAI, Mastra, Google ADK, docs 2026-07-06	Full
Workflow OrchestrationObserves and tests agents but is not an orchestrator	Unable to verify
Knowledge Grounding & RAGEvaluates RAG apps but provides no knowledge grounding	Unable to verify
Human Oversight & GuardrailsInline gateway guardrails plus human annotation and review queues, docs 2026-07-06	Partial
Security, Identity & GovernanceGateway virtual keys and budgets plus self host and on prem for residency; enterprise identity less documented, docs 2026-07-06	Partial
Observability & AuditabilityCore product: OpenTelemetry native tracing of prompts, tool calls, and agent behavior, docs 2026-07-06	Full
Memory & State PersistenceNo agent memory layer	Unable to verify
Deployment & Data ResidencyCloud, self host via Docker or Helm, on prem for AWS, GCP, Azure, and hybrid for residency, docs 2026-07-06	Full
Prebuilt Agents, Templates & PacksPrebuilt evaluators and scenario scaffolding exist but no prebuilt agents	Unable to verify
Triggers & Channel CoverageNo production event triggers or channel coverage	Unable to verify
Model Flexibility & RoutingProvider agnostic with a bundled gateway offering fallback across providers, secondary to the core product	Partial
APIs, SDKs & MCP ExtensibilityOpenTelemetry native, SDK, API, MCP support for Claude Desktop, webhooks, docs 2026-07-06	Full
Testing, Debugging & OptimizationCore capability: evaluations plus multi turn agent simulation and scenario testing, docs 2026-07-06	Full
Browser & Computer UseNo browser or computer use	Unable to verify

Recent platform changes

No recent material changes tracked yet.

View all changes for LangWatch →

Pricing

Open source self host free; free cloud (200k events/mo); about $31 (29 euro) per seat plus usage

seats plus events

Public — exactMedium variable costFree tier

Included quota

Open source self host is free with the full feature set. Free cloud tier includes 200,000 events a month. Paid cloud is about 29 euro per seat, with unlimited lite seats for sharing results, plus usage at one dollar per 100,000 additional events.

What is public

The free event allowance, per seat euro price, and event overage rate are published.

Billing mechanics

Free open source self host, or cloud with a free 200,000 event tier and paid seats at about 29 euro each (unlimited lite seats for viewers), plus event based usage at one dollar per 100,000 events.

Cost watchouts

Events accrue across traces, evaluations, and simulations, so heavy agent testing and production volume can move you past the 200,000 event free allowance faster than expected, billed at one dollar per 100,000 events. Full seats (beyond unlimited lite seats) add per seat cost.

Variable cost rationale

A per seat floor is predictable, but event based usage across traces, evaluations, and simulations scales with testing and production volume, and self hosting shifts cost to your own infrastructure.

Overage / add-ons

Additional events above the included allowance bill at one dollar per 100,000 events.

Sales call required

Mixed (some tiers require a call)

Free / trial

Apache 2.0 open source free to self host, plus a free cloud tier of 200,000 events a month

Lowest paid plan

About 29 euro per seat plus usage, or free via self hosted open source

Commercial notes

Independent, open source under Apache 2.0, used by thousands of AI developers. Distinctive for agent simulation and a bundled AI gateway.

Key ambiguities

Seat pricing is quoted in euro (about 29 euro), so the dollar figure varies with exchange rate; enterprise terms may differ.

Verified 2026-07-06

Official pricing page

Data confidence: high