playwright

Provides a single high-level Python API that abstracts over Chromium, Firefox, and WebKit browser engines, translating method calls into the Chrome DevTools Protocol (CDP) or equivalent wire protocols for each browser. Uses an async/await pattern with context managers for resource lifecycle management, enabling developers to write browser automation code once and run it against multiple engines without engine-specific branching logic.

Intercepts HTTP/HTTPS requests at the browser protocol level before they reach the network, allowing modification of request headers, bodies, and URLs, or replacement with mock responses without touching the application code. Uses route handlers registered on page or context objects that match requests by URL pattern or custom predicates, enabling test isolation and deterministic response injection.

Mocks browser permissions (camera, microphone, geolocation, notifications) and geolocation coordinates at the context level, allowing tests to simulate location-based features and permission prompts without user interaction. Uses the Chrome DevTools Protocol to inject mock permission states and geolocation data, enabling testing of location-aware applications and permission-gated features.

Provides utilities to inspect accessibility tree (ARIA roles, labels, descriptions) and validate semantic HTML structure, enabling automated accessibility testing without external tools. Exposes element roles, accessible names, and descriptions through the accessibility tree, allowing assertions on keyboard navigation, screen reader compatibility, and WCAG compliance.

Provides CSS selector, XPath, and text-based element locators that automatically wait for elements to become actionable (visible, enabled, stable) before performing actions like click, fill, or type. Uses internal polling with exponential backoff and timeout configuration to handle dynamic DOM updates, reducing flakiness from race conditions between script execution and DOM rendering.

Captures visual snapshots of pages or specific elements as PNG/JPEG images or full-page PDFs, with options for full-page scrolling capture, clipped regions, and custom viewport sizing. Renders the page through the browser's rendering engine at specified dimensions, enabling pixel-perfect visual regression testing and documentation generation without external screenshot tools.

Creates isolated browser contexts (equivalent to private browsing sessions) with independent cookies, local storage, session storage, and IndexedDB, allowing parallel test execution without cross-contamination. Contexts can be pre-populated with authentication state, cookies, or storage data, and state can be persisted to disk and reloaded, enabling test setup optimization and session replay.

Captures browser performance metrics (page load time, DOM content loaded, first contentful paint) and network activity (requests, responses, timing) through the Chrome DevTools Protocol, exposing raw HAR (HTTP Archive) files and parsed metrics for performance analysis. Enables real-time network monitoring without external proxy tools or performance monitoring libraries.

Simulates keyboard and mouse events (type, press, click, drag, hover) with configurable timing and delay between actions, enabling realistic user interaction patterns. Uses the browser's input event system to trigger native events (keydown, keyup, mousemove, mousedown, mouseup) rather than directly manipulating DOM, ensuring event handlers and form validation logic execute as they would for real user input.

Executes arbitrary JavaScript code in the page context with access to the DOM, window object, and page state, returning serialized results back to Python. Supports both synchronous evaluation (evaluate) and asynchronous evaluation (evaluate_handle) with automatic serialization of return values, enabling dynamic page inspection and manipulation beyond the high-level API.

Records browser sessions as video files (MP4) and/or detailed trace files (ZIP archives containing screenshots, network logs, and DOM snapshots) for post-test debugging and analysis. Traces capture the full execution timeline with screenshots at each step, enabling visual replay of test execution without re-running the test, and network logs for debugging API interactions.

Emulates mobile devices (iPhone, Android phones, tablets) with predefined profiles that set viewport size, device pixel ratio, user agent, touch capabilities, and other device-specific properties. Uses the Chrome DevTools Protocol to apply device emulation at the browser level, enabling testing of responsive designs and mobile-specific behaviors without physical devices.