LangWatch

Overview

LangWatch is a simulation-based AI agent testing and evaluation platform that turns unpredictable agents into reliable production systems. Self-host in 15 minutes with agentic AI testing that runs realistic user scenarios against your agent to catch issues before production.

It provides LLM evaluation to measure response quality and accuracy, LLM observability to trace every agent step and monitor cost and latency, and AI governance with virtual keys, budgets, routing policies and a full audit trail. Prompt management versions, deploys and A/B tests prompts as code with GitHub sync.

Voice AI testing simulates voice agents at scale, and LLM red-teaming uncovers safety and security gaps. Track Claude Code, Codex and coding agent usage with full trace history and token spend.

Core capabilities

Agentic AI testing

Realistic user scenarios

LLM evaluation

Response quality and accuracy

LLM observability

Trace, cost and latency

AI governance

Virtual keys and audit trail

Prompt management

Version and A/B test as code

Voice AI testing

Simulate at scale

Red-teaming

Safety and security gaps

Claude Code tracking

Token spend visibility

Self-host

In 15 minutes

Use cases

AI agent testing

LLM evaluation

Observability

Prompt management

AI governance