LangWatch
Open-source testing platform for AI agents. Run simulations, catch regressions, and ship autonomous agents with confidence. Built for developers who treat AI like software. Agent simulations are the new unit tests
| What is it | Open-source testing platform for AI agents. Run simulations, catch regressions, and ship autonomous agents with confidence. Built for developers who treat AI like software. Agent simulations are the new unit tests |
|---|---|
| Pricing | Freemium — from €59/mo |
| Free tier | Yes |
| Platform | Web Application |
| API | Yes |
| Works with | n8n |
| Best for | Monitoring AI chatbot performance in production, Testing LLM responses against quality criteria |
| Domain registered | 2023 |
Data updated Aug. 1, 2026
What does LangWatch do?
LangWatch is a comprehensive observability and testing platform designed specifically for AI applications. It provides developers with tools to monitor AI agent performance in real-time, run evaluations on large language models (LLMs), and debug issues across the entire AI workflow. The platform captures detailed traces of AI interactions, allowing you to see exactly how your models are performing in production environments.
The platform stands out with its robust evaluation framework that lets you test AI responses against custom criteria, run simulated user conversations to stress-test agents before deployment, and maintain datasets for consistent testing. It offers collaboration features for teams, analytics dashboards to track performance metrics, and supports both cloud-based and self-hosted deployments for enterprise needs.
This tool is essential for AI engineers, product teams building AI features, and companies deploying LLM-powered applications. Real-world use cases include monitoring customer support chatbots to ensure quality responses, testing document analysis agents for accuracy, and maintaining reliability in AI-powered workflow automation systems where consistency is critical.
Key features
What makes it stand outWho is LangWatch for?
Who benefits most from this toolPricing
Free tier available — start without a credit cardDeveloper
- 2 users
- 14 data access days
- 50,000 logs and evals per month
- All platform features
- Community Support (Github & Discord)
Launch
Everything in Developer, plus:
- 3 users included
- 180 data access days
- 19 additional user price
- 120,000 events per month included
- 20,000 traces per month included
- 5 additional traces price per 10k
- Everything in Developer
- Unlimited Evaluations
- Unlimited Optimizations
- Slack and Email Support
Accelerate
Everything in Launch, plus:
- 5 users included
- 365 data access days
- 15 additional user price
- 120,000 events per month included
- 20,000 traces per month included
- 45 additional traces price per 100k
- Everything in Launch
- ISO27001 reports
Enterprise
- custom data retention
- custom traces per month
- Tiered usage pricing
- Custom data retention
- Audit logs
- Uptime & Support SLA
- InfoSec/legal reviews
- Custom Terms, DPA
- Forward Deployed Engineer
- Billing via AWS or Azure Marketplace
Trust & presence
Gallery
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