Launched July 7, 2026
LangWatch
The harder your agents get, the more you need LangWatch.
FreeAI Agents1,197 impressions#12 of its week
LangWatch is the open-core platform to test, simulate, and monitor AI agents end-to-end. Unlike tools that grade single LLM outputs, LangWatch is built for agent complexity; multi-turn, multi-step, multi-agent systems where failure hides in the interactions. Killer feature: Scenario, agent simulation before production. Open-source framework for simulating full multi-turn agent conversations, including adversarial and edge-case paths, so you catch broken behavior before your users do. This is the wedge: almost every competitor evaluates outputs; LangWatch tests agents the way software teams test software. Voice agents included
LangWatch is an open-core platform for simulating, testing and monitoring multi-turn AI agents end-to-end.
- for
- AI engineers, product managers and teams building production AI agents.
- pricing
- freemium · free trial
- license
- Apache-2.0
- v3.20.1a month ago
- v3.20.0a month ago
- langwatch@v3.20.1langwatch: v3.20.1a month ago
works withLangGraphCrewAIPydantic AIOpenTelemetryLiteLLM proxy
Key features
6 features of LangWatch
- Scenario-driven simulations — Write plain-language scenarios that generate multi-turn conversations for agents.
- Red-team adversarial testing — Run adversarial simulations to surface jailbreaks, policy breaks and unsafe tool calls.
- Judge agent evaluation — LLM or custom judges score whole conversations with reasoning and pass/fail verdicts.
- Observability & tracing — Full OpenTelemetry-compatible traces of every token, tool call, cost and latency.
- CI/CD integration — Run simulations and evaluations locally or in pipelines on pull requests.
- Voice agent testing — End-to-end voice simulations with latency metrics and noise/interruption injection.
Use cases
- Validate a new customer-support chatbot across thousands of possible dialogue paths before release.
- Detect safety violations in a financial advice agent by red-team adversarial simulations.
- Continuously evaluate production traffic to monitor drift in response quality.
- Generate regression tests from production traces and automatically open PRs for fixes.
LangWatch pricing
- Developer$050k events / month · 2 users · 3 scenarios, simulations, evals · Community support
- Growth$34/core-seat / month200k events included (+ $6 / 100k) · Unlimited simulations & evals · Private Slack/Teams support · Volume discounts >20 users
LangWatch vs alternatives
 LangWatch |  LangChain |  CrewAI |  LangGraph |  LlamaIndex | |
|---|---|---|---|---|---|
| Best for | Simulation-based testing for complex agents | LLM app framework | Multi-agent orchestration | Stateful agent framework | Data-centric agent apps |
| Pricing | Freemium | Free | Subscription | Free | Free |
| DevHunt upvotes | 1 | 0 | 0 | 0 | 0 |
| Launched | Jul 2026 | — | — | — | — |
- LangWatch vs LangChain: LangChain is a developer library for building agents, while LangWatch provides a full testing and observability platform.
- LangWatch vs CrewAI: CrewAI focuses on multi-agent orchestration; LangWatch adds simulation, red-team and production monitoring.
- LangWatch vs LangGraph: LangGraph offers stateful agent building; LangWatch adds end-to-end testing, evaluation and tracing.
- LangWatch vs LlamaIndex: LlamaIndex helps retrieve data for agents; LangWatch concentrates on testing, evaluation and observability of agent behavior.
LangWatch FAQ
Do I need a credit card to start?+
No. The Developer plan is free forever and requires no credit card.
Can I self-host LangWatch?+
Yes. It can be run with Docker Compose on your own infrastructure, keeping all data on-premise.
How does billing work?+
Seats are billed per core-seat ($34/month for Growth) plus usage: $6 per 100k events beyond the included allowance and $4 per GB of storage beyond 30-day retention.
What counts as a billable event?+
Each LLM call, tool call, retrieval, evaluation or simulation step is counted as an event.
Can I change or cancel my plan?+
Yes, you can upgrade, downgrade or cancel at any time.
Summarized by DevHunt from langwatch.ai · Oct 12, 2026. Details may change; check the official site.
