configure per-project locale and timezone emulation in playwright using use.locale and use.timezoneid
domain: playwright.dev · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
set a default locale (e.g. 'en-GB') and timezoneId (e.g. 'Europe/Paris') in the top-level use block of playwright.config.ts
define additional projects in the config, each overriding locale and timezoneId to represent different regional test scenarios (e.g. a 'de-DE' / 'Europe/Berlin' project)
within an individual test, call test.use({ locale: '...', timezoneId: '...' }) to override the project defaults for that specific test file or describe block
assert on locale-sensitive behavior such as navigator.language, the Accept-Language request header, and date/number formatting rendered by the page
set the TZ environment variable separately if the Node.js test runner's own timezone (not just the emulated browser timezone) needs to match
Known gotchas
locale and timezoneId only affect the emulated browser context, not the Node.js process running the test runner -- date logic evaluated outside the page (e.g. in test assertions using JS Date) still uses the runner's own TZ
invalid or unsupported timezoneId strings are rejected at context-creation time, so IANA timezone names must be used exactly (e.g. 'America/New_York', not an abbreviation)
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