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LangWatch

langwatch.ai

From €29/mo Free plan Open source WebmacOSLinuxAPISelf-hosted
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Spec score 9.1 #5 of 31 in AI Agent Observability Tools

What it is

LangWatch is an AI agent engineering platform for teams preparing agents for production. Simulations cover multi-turn conversations, tool use, recovery, and business outcomes before launch. Evaluations can run on datasets, production traffic, or in CI/CD workflows that gate merges. Traces show agent steps alongside cost, tokens, duration, errors, evaluations, and annotations. Integrations include Python and TypeScript SDKs, OpenTelemetry, REST ingestion, model providers, and frameworks such as LangGraph, LangChain, CrewAI, and DSPy. Voice-agent testing supports OpenAI Realtime, Gemini, ElevenLabs, Google Live API, Pipecat, WebSocket bots, and Twilio. Deployment options are managed cloud, self-hosted, and hybrid; self-hosting uses Docker Compose and the customer’s ClickHouse. LangWatch is open source under Apache 2.0. The Developer plan costs nothing and includes 50k events per month, 14-day data access, and two users. Growth costs €29 a month per core seat and includes 200k events. The trust center lists encryption, access controls, privacy features, and enterprise DPAs.

Spec sheet

What it does
LangWatch is an AI-agent engineering platform for testing, evaluating, observing, governing and improving agents across development and production.Read 21 Oct 2026 · crunchbase.com
Product
LangWatch describes itself as an AI agent engineering platform for helping teams ship reliable agents to production.Read 5 Oct 2026 · langwatch.ai
Intended users
The company says the platform is for AI teams shipping agents and describes evaluation workflows for developers, product owners, QA, and domain experts.Read 5 Oct 2026 · langwatch.ai
Deployment
LangWatch offers managed cloud, self-hosted, and hybrid deployment; its pricing page says self-hosting uses Docker Compose and the customer's ClickHouse.Read 5 Oct 2026 · langwatch.ai
Integrations
Official integrations cover OpenAI, Anthropic, Google Gemini, Bedrock, Azure OpenAI, Vertex AI, Groq, Ollama and LiteLLM.Read 21 Oct 2026 · langwatch.ai
Security
The trust center states AES-256 encryption at rest, TLS 1.2+ in transit, AWS KMS, RBAC, MFA, SSO, encrypted backups and GDPR controls.Read 21 Oct 2026 · langwatch.ai
Privacy
The trust center says LangWatch provides automatic PII detection and removal, GDPR right-to-be-forgotten, and enterprise DPAs.Read 5 Oct 2026 · langwatch.ai
Compliance
LangWatch states ISO 27001 certification, GDPR compliance, EU data residency and SOC 2 coverage through AWS.Read 21 Oct 2026 · langwatch.ai
Support
Developer users receive GitHub and Discord community support, while Growth includes private Slack or Teams support.Read 21 Oct 2026 · langwatch.ai
Headquarters
AmsterdamRead 28 Sep 2026 · langwatch.ai
Company
The site's footer identifies the maker as LangWatch B.V. and says it is built in Amsterdam.Read 5 Oct 2026 · langwatch.ai
Agent simulations
It runs realistic multi-turn text and voice simulations with simulated users, judges, tool-call verification and visual run debugging.Read 21 Oct 2026 · langwatch.ai
AI gateway
The AI Gateway provides an OpenAI- and Anthropic-compatible endpoint with virtual keys, budgets, routing and provider fallbacks.Read 21 Oct 2026 · github.com
AI governance
Governance features include organization-wide policy controls, audit exports, spend dashboards and inventory of AI tools.Read 21 Oct 2026 · github.com
CLI and MCP
The project provides a CLI and an MCP server for use with coding assistants and other MCP clients.Read 21 Oct 2026 · langwatch.ai
Company founded
LinkedIn lists LangWatch as founded in 2023.Read 21 Oct 2026 · linkedin.com
Company headquarters
LinkedIn lists headquarters at Herengracht 551, Amsterdam, Netherlands.Read 21 Oct 2026 · linkedin.com
Company legal name
Crunchbase identifies the operating legal entity as Reasoning Engine B.V.Read 21 Oct 2026 · crunchbase.com
Company size
LinkedIn lists the company size as 11–50 employees.Read 21 Oct 2026 · linkedin.com
Documentation
Documentation covers introduction, integrations, CLI, MCP, agent testing, observability, evaluations, datasets, prompt management, self-hosting and API reference.Read 21 Oct 2026 · langwatch.ai
Evaluations
The platform supports offline and online evaluations, CI/CD gates, multimodal scoring, built-in evaluators and custom workflows.Read 21 Oct 2026 · langwatch.ai
Framework integrations
Framework support includes OpenAI Agents, LangGraph, LangChain, CrewAI, Pydantic AI, Agno, Mastra, Vercel AI SDK, Google ADK, LangFlow and Flowise.Read 21 Oct 2026 · langwatch.ai
Funding
Crunchbase lists LangWatch as a private pre-seed company with two funding rounds and investors including Volta Ventures and Antler.Read 21 Oct 2026 · crunchbase.com
Licence
The core platform is Apache 2.0; enterprise modules require a commercial production licence and the SDKs are MIT licensed.Read 21 Oct 2026 · github.com
Limit: review evidence
G2 says there are insufficient LangWatch reviews to provide buying insight, and Software Advice lists no user reviews.Read 21 Oct 2026 · g2.com
Limit: service reliability
The public status page shows Scenarios at 96.174% uptime and Langy at 96.823% uptime for the displayed 30-day period.Read 21 Oct 2026 · status.langwatch.ai
Notable news: latest release
The GitHub releases page lists version 3.20.1 released October 2, 2026, including a self-hosted SSO sign-in fix.Read 21 Oct 2026 · github.com
Notable news: open source
LangWatch announced on May 31, 2026 that the complete platform became open source under Apache 2.0.Read 21 Oct 2026 · langwatch.ai
Observability
Tracing captures nested agent spans, sessions, users, token usage, cost, topics and multimodal payloads.Read 21 Oct 2026 · langwatch.ai
Open source
The site describes LangWatch as open source under Apache 2.0.Read 5 Oct 2026 · langwatch.ai
Praise: agent testing
Product Hunt reviewers repeatedly praise the open-source agent simulations, regression detection, intuitive API and visualization.Read 21 Oct 2026 · producthunt.com
Praise: monitoring and safety
Product Hunt reviewers describe strong output monitoring, RAG evaluation, jailbreak detection, hallucination diagnosis and safety improvements.Read 21 Oct 2026 · producthunt.com
Prompt management
Prompts can be versioned through code, UI and API, templated with Liquid, synced with GitHub and compared in experiments.Read 21 Oct 2026 · langwatch.ai
Rating on G2
0.0 out of 5 from 0 reviewsRead 21 Oct 2026 · g2.com
Rating on Product Hunt
5.0 out of 5 from 5 reviewsRead 21 Oct 2026 · producthunt.com
Rating on Software Advice
No rating out of 5 from 0 reviewsRead 21 Oct 2026 · softwareadvice.com
SDKs and API
LangWatch publishes Python and TypeScript SDKs, OpenTelemetry ingestion and a direct REST API for sending spans.Read 21 Oct 2026 · langwatch.ai
Self-hosting
Self-hosting is available with a Node.js command for local use and Docker, Kubernetes/Helm or VPC deployment options.Read 21 Oct 2026 · github.com
System requirements
The self-host command requires Node.js 24 or newer on macOS or glibc-based Linux.Read 21 Oct 2026 · github.com
Voice testing
Voice-agent testing supports OpenAI Realtime, Gemini, ElevenLabs, Google Live API, Pipecat, WebSocket bots, and Twilio.Read 5 Oct 2026 · langwatch.ai

Plans and prices

Developer Free free forever 50k events/month · 14-day data access · 2 users · 3 scenarios · 3 simulations · 3 custom evals · community support Read 21 Oct 2026 · langwatch.ai
Growth €29 a month per core-seat/month 200k events included · €5/100k additional events · 30-day retention · €3/GB beyond retention · unlimited lite users · unlimited simulations, evals and prompts · private Slack/Teams support Read 21 Oct 2026 · langwatch.ai
Enterprise Priced on request custom pricing hybrid/self-hosted/on-prem · custom retention · SSO/RBAC · audit logs and SLAs · ISO 27001 reports · DPA/custom terms · dedicated engineering support · cloud marketplace billing Read 21 Oct 2026 · langwatch.ai

Every LangWatch plan and price →

Strong points and limits

Strong points

  • Simulates conversations, tool use, and recovery.
  • Evaluations can gate CI/CD merges.
  • Traces report cost, tokens, duration, and errors.
  • Open source under Apache 2.0.

Limits

  • Developer plan limits data access to 14 days.
  • Developer plan allows two users.
  • Self-hosting uses the customer’s ClickHouse.

Who it suits

LangWatch suits AI teams shipping agents, including developers, product owners, QA, and domain experts working with evaluation workflows. Teams can choose managed cloud, self-hosted, or hybrid deployment.

Verdict

LangWatch brings agent simulations, evaluations, and tracing into one platform with multiple deployment options. Review the Developer plan’s limits or Growth’s per-core-seat pricing when estimating fit.

Where Specifiction places it

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