LangWatch
Testing, evaluation, observability, and governance for AI agents.
Pricing
Freemium
- LangWatch runs simulations that exercise agents with realistic user behavior in text and voice. These scenarios help teams test agent behavior before it reaches production.
- The platform evaluates a single output or an entire conversation using LLMs, custom code, or workflows. It supports offline experimentation and online evaluation of live production traffic.
What is LangWatch?
LangWatch is a platform for testing, evaluating, and observing AI agents. It is built for teams that want to make agent behavior more reliable before and after release.
The product uses simulations to test agents against realistic text and voice interactions. Teams can run scenarios locally and in continuous integration, then use production traces to reproduce and verify fixes.
LangWatch also supports evaluation workflows for individual outputs and complete conversations. It can score offline experiments and evaluate production traffic in real time.
For observability, the platform traces agent activity, token use, and cost across frameworks. Its OpenTelemetry support is designed to work with OTel-compatible stacks.
LangWatch has a free Developer plan and paid Growth and Enterprise options. The paid offering combines seat-based and usage-based pricing, with self-hosting available.
Agent simulations
LangWatch runs simulations that exercise agents with realistic user behavior in text and voice. These scenarios help teams test agent behavior before it reaches production.
- Scenarios can run locally and on every pull request.
LLM evaluations
The platform evaluates a single output or an entire conversation using LLMs, custom code, or workflows. It supports offline experimentation and online evaluation of live production traffic.
- Production traffic can be evaluated in real time.
Agent observability
LangWatch records traces, token usage, and cost for agent applications. Its observability layer is intended to work across frameworks and OpenTelemetry-compatible stacks.
- The platform supports the GenAI OpenTelemetry specification.
Adversarial testing
LangWatch includes red-team simulations for probing AI agent safety and tool-use behavior. Teams can use these tests to surface jailbreaks, policy violations, and unsafe tool calls.
- Tool calls and MCP servers are traced and can be made deterministic for tests.
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