Playwright Core Testing

Opinionated, production-tested Playwright guidance — every pattern includes when (and when not) to use it.

46 reference guides covering the full Playwright testing surface: selectors, assertions, fixtures, network mocking, auth, visual regression, accessibility, API testing, debugging, and more — with TypeScript and JavaScript examples throughout.

Golden Rules

1. getByRole()

   over CSS/XPath — resilient to markup changes, mirrors how users see the page
2. Never

   page.waitForTimeout()

   — use

   expect(locator).toBeVisible()

   or

   page.waitForURL()

3. Web-first assertions —

   expect(locator)

   auto-retries;

   expect(await locator.textContent())

   does not
4. Isolate every test — no shared state, no execution-order dependencies

5. baseURL

   in config — zero hardcoded URLs in tests
6. Retries:

   2

   in CI,

   0

   locally — surface flakiness where it matters
7. Traces:

   'on-first-retry'

   — rich debugging artifacts without CI slowdown
8. Fixtures over globals — share state via

   test.extend()

   , not module-level variables
9. One behavior per test — multiple related

   expect()

   calls are fine
10. Mock external services only — never mock your own app; mock third-party APIs, payment gateways, email

Guide Index

Writing Tests

What you're doing	Guide	Deep dive
Choosing selectors	locators.md	locator-strategy.md
Assertions & waiting	assertions-and-waiting.md
Organizing test suites	test-organization.md	test-architecture.md
Playwright config	configuration.md
Fixtures & hooks	fixtures-and-hooks.md
Test data	test-data-management.md
Auth & login	authentication.md	auth-flows.md
API testing (REST/GraphQL)	api-testing.md
Visual regression	visual-regression.md
Accessibility	accessibility.md
Mobile & responsive	mobile-and-responsive.md
Component testing	component-testing.md
Network mocking	network-mocking.md	when-to-mock.md
Forms & validation	forms-and-validation.md
File uploads/downloads	file-operations.md	file-upload-download.md
Error & edge cases	error-and-edge-cases.md
CRUD flows	crud-testing.md
Drag and drop	drag-and-drop.md
Search & filter UI	search-and-filter.md

Debugging & Fixing

Problem	Guide
General debugging workflow	debugging.md
Specific error message	error-index.md
Flaky / intermittent tests	flaky-tests.md
Common beginner mistakes	common-pitfalls.md

Framework Recipes

Framework	Guide
Next.js (App Router + Pages Router)	nextjs.md
React (CRA, Vite)	react.md
Vue 3 / Nuxt	vue.md
Angular	angular.md

Specialized Topics

Topic	Guide
Multi-user & collaboration	multi-user-and-collaboration.md
WebSockets & real-time	websockets-and-realtime.md
Browser APIs (geo, clipboard, permissions)	browser-apis.md
iframes & Shadow DOM	iframes-and-shadow-dom.md
Canvas & WebGL	canvas-and-webgl.md
Service workers & PWA	service-workers-and-pwa.md
Electron apps	electron-testing.md
Browser extensions	browser-extensions.md
Security testing	security-testing.md
Performance & benchmarks	performance-testing.md
i18n & localization	i18n-and-localization.md
Multi-tab & popups	multi-context-and-popups.md
Clock & time mocking	clock-and-time-mocking.md
Third-party integrations	third-party-integrations.md

Architecture Decisions

Question	Guide
Which locator strategy?	locator-strategy.md
E2E vs component vs API?	test-architecture.md
Mock vs real services?	when-to-mock.md