playwright-best-practices

Use user-centric locators in this priority order: page.getByRole() for accessibility-checked elements, page.getByText() for visible text, and page.getByTestId() for stable data-testid attributes. Avoid CSS selectors and XPath, which break when layout or styling changes.

Use page.route() with a URL pattern to intercept outgoing requests, then call route.fulfill() with a custom status and JSON body. This removes dependence on external services like payment processors, making tests deterministic and fast.

Flakiness usually comes from hardcoded waitForTimeout calls, cascading tests that share state, or parallel workers competing for resources. Replace sleeps with auto-waiting locators, isolate each test with beforeEach setup, and set retries and workers appropriately in playwright.config.ts.

Yes, Playwright supports Chromium, WebKit, and mobile viewports through projects in playwright.config.ts. You can define entries like Desktop Chrome, Desktop Safari, and iPhone 13 using the devices presets, and run them in parallel with fullyParallel enabled.

Use test.describe.configure({ mode: 'serial' }) only when tests have genuine ordering dependencies that cannot be removed. Prefer isolated tests with independent setup, since serial execution slows the suite and often hides design problems in test structure.