LangWatch
Simulation-based testing and evaluation that turns unpredictable AI agents into reliable systems.
About LangWatch
LangWatch is an open-source, framework-agnostic platform for testing, evaluating, observing, and optimizing AI agents and LLM applications. It uses simulation-based testing with real-user text and voice conversations, LLM-as-a-judge evaluations, red teaming, and OpenTelemetry-native observability to catch issues and prevent regressions. It supports collaboration between technical and non-technical teams and can be deployed as cloud, self-hosted, or hybrid.
Screenshots
Commonly Cited Strengths & Limitations
Strengths
- Collaboration features praised by users
- Simulations provide concrete evidence that issues are fixed
- Speeds up testing setup (from half a day to ten minutes)
Common Use Cases
- Ensuring reliable AI agent performance and preventing regressions
- Turning production traces into simulations to reproduce and prove fixes
- Spec-driven agent building from plain-language requirements
- Collaborative LLM application development and optimization
- Gaining observability and optimizing LLM costs and performance
- Deploying secure, compliant enterprise-grade LLM systems
- Adversarial red teaming for jailbreaks and unsafe tool calls
Details
- Pricing Model
- Freemium
- Starting Price
- $0/mo
- Team Size
- Startup, Business, Enterprise
- Category
- AI & Machine Learning
Key Features
- Agent Simulations
- Text and voice user simulation
- Scenario testing
- Local and CI testing
- Red teaming / adversarial simulations
- LLM as a judge (JudgeAgent)
- Tool, skill, and MCP tracing with mocking/fixtures
- Whitebox and blackbox testing
Official Pricing
LangWatch's published plans
Developer
$0/mo
- LLM monitoring & tracing with traces and graphs
- Conversation/session thread tracking
- User tracking
Real Pricing from Verified Users
See what people actually pay for LangWatch
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