LangWatch: AI Agent Testing and LLM Evaluation Platform

Categories: Coding & Developer Tools, Automation / Agents, Data Analysis | Pricing: Freemium | Official Website ↗

LangWatch is an AI engineering platform for testing, evaluating, and monitoring AI agents and LLMs pre- and in production.

LangWatch provides a developer-first platform for defining evaluations, running experiments, simulating multi-step agent behavior, and monitoring production signals. This allows teams to test and validate changes to prompts, models, or agents before deployment, preventing regressions and quality degradation. The platform helps ship reliable AI by addressing issues like agents breaking or behaving differently in production, model swaps degrading quality, or prompt changes introducing regressions. The platform offers features for prompt and model management, real-time evaluations, and LLM observability. It enables users to version, compare, and deploy prompt and model changes with full traceability, create custom evaluations, and instantly search and inspect LLM interactions across environments for debugging and incident investigation. LangWatch also supports agent simulations for complex AI, batch tests, and auto-evaluations for both pre-release testing and production monitoring.

Key Features

AI Agent Simulations
LLM Evaluation (Offline & Real-time)
Prompt & Model Management
LLM Observability (Traces & Graphs)
Auto-Evals & Batch Tests
Data Review & Labeling
Dataset Management
Performance Optimization with DSPy

Pros

Simulates real-world conversations for agent testing
Provides structured evaluations to prevent issues before deployment
Offers full traceability for prompt and model changes
Supports collaborative workflows for teams
Includes safeguards against common LLM vulnerabilities like jailbreaking
Available as self-hosted or hybrid deployment for control

Cons

Pricing for Growth plan is per core-seat, which might scale quickly
Limited data retention on lower-tier plans
Specific pricing for Growth plan beyond included events is not immediately clear (e.g., €0,0005 per event)
Requires technical expertise for full utilization
No explicit mention of a free trial for paid plans, only a free tier

Use Cases

Testing AI agents pre-production
Evaluating LLM performance and quality
Monitoring AI features in production
Debugging LLM failures and incidents
Optimizing prompts and models
Ensuring AI agent reliability and safety

Best For

AI developers
AI engineering teams
Product managers working with AI
Organizations shipping complex AI agents
Companies requiring robust LLM quality control

Integrations: OpenTelemetry, DSPy, GitHub, Discord, Slack, Teams, AWS Marketplace, Google Marketplace, Azure Marketplace

Platforms: Web

Watch demo on YouTube ↗

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