Engineering teams shipping agents get simulated testing and tracing, with a usable free tier and a self-hosting option.

Kenning's take

What it does

LangWatch tests AI agents by running simulated user conversations against them, scores their answers with evaluations, and traces every step in production with cost and latency. It also offers prompt management, an AI gateway, red-teaming and voice agent testing, plus tracking for coding agents such as Claude Code and Codex. It can be used in the cloud or self-hosted.

• Simulation-based agent testing
• LLM evaluations and instant evals over production history
• Tracing with cost and latency monitoring
• Prompt management with GitHub sync
• AI gateway with per-team budgets
• Red-teaming and voice agent testing

Who it suits. Engineering teams putting AI agents into production who need repeatable tests and monitoring.

Key facts

Category

Developer tools

Made by

LangWatch B.V.

Based in

Netherlands

How to get it

self-serve cloud sign-up with a free plan, self-hosting, or Enterprise through sales

Works on

Web, API, self-hosted

In the UK

Yes

Free plan

Developer plan: 50k events a month, 2 users, 14-day data access

API price

Growth includes 200k events, then €5 per 100k events

Pricing

Plan	Price	Billed
Developer	€0	month
Growth	€29	month, per core seat
Enterprise	Custom pricing	custom

source

FAQ

Facts from the maker's own pages and the sources listed. Checked 2026-10-11.