Chromatic

Open-source visual regression testing tool

Lost Pixel is an open-source visual regression testing tool that serves as an alternative to Percy and Chromatic. It captures and compares screenshots of UI components and application pages across Storybook, Ladle, Histoire, and custom screenshot sources like Cypress or Playwright. Integrated directly into GitHub Actions pipelines, it detects unintended visual changes before they reach production, with a free SaaS tier available for open-source projects.

Cloud browser infrastructure for AI agents

Anchor Browser provides secure cloud-managed browser infrastructure for computer-use agents. Deploy humanized Chromium instances that access any website while maintaining bot-detection evasion and authentication support. Features OmniConnect for authentication lifecycle management, Web Action Cache for deterministic workflows, and built-in VPN infrastructure. Includes free tier and paid plans supporting millions of concurrent browser sessions for scalable agent automation.

Apple's Safari-native MCP server for web debugging agents

Safari MCP Server is Apple's safaridriver-based MCP server in Safari Technology Preview, giving compatible coding agents local access to Safari page content, console logs, network requests, screenshots, JavaScript evaluation, interactions, viewport controls, and accessibility/performance checks.

Microsoft’s pytest-native red teaming framework for turning AI agent safety findings into CI tests.

RAMPART is an open-source Microsoft framework for safety and security testing of agentic AI applications. It brings red-team findings into a pytest-native workflow so teams can turn prompt injection, unsafe tool use, and behavioral boundary failures into repeatable regression tests. The strongest aicoolies angle is developer workflow: RAMPART makes agent safety part of CI/CD instead of a one-off security review.

One tool for intercepting, mocking, and replaying HTTP — acquired by BrowserStack

Requestly is a BrowserStack-backed API client, HTTP interceptor, mock server, and session replay tool for frontend and QA teams. Its current product is commercial/API-client led, while the legacy interceptor/open-source code is AGPLv3. The free plan covers individual workflows, and Pro lists at $12/user/month monthly or $9/user/month annually for collaborative QA and frontend debugging teams.

Headless browser cloud built for AI agents

Browserbase is cloud infrastructure that runs headless Chromium browsers on demand for AI agents and automation workflows, exposing Playwright, Puppeteer, and Selenium endpoints with built-in session replay, residential proxies, CAPTCHA solving, and stealth fingerprints. It also hosts Stagehand and a Model Gateway, letting teams build browser-using agents without maintaining their own fleet of Kubernetes-managed Chromium instances.

AI testing and evaluation for agents and LLM apps

RagaAI Catalyst is a comprehensive Python SDK for observability, monitoring, and evaluation of LLM and agentic applications. Provides agent tracing with execution graph visualization, self-hosted dashboard with analytics, synthetic data generation, multi-metric evaluation framework, and guardrail management. Built for teams running production RAG systems and AI agents who need systematic testing, debugging, and performance optimization workflows.

Open-source observability for AI agents

Laminar is an open-source observability platform for AI agents providing tracing, evaluation, and analytics for LLM applications. It integrates with Vercel AI SDK, LangChain, OpenAI, and Anthropic with a single line of code. Features include OpenTelemetry-native SDKs, an extensible evaluation framework with CI/CD support, SQL access to traces and metrics, and a visual debugging timeline for agent reasoning and actions.