Playwright · Senior · Question 21 of 77

Why can headless and headed runs behave differently?

1Focus, GPU, window size and timing differ
2Headed mode runs a different JavaScript engine
3Headless mode skips CSS and loads only HTML

Show the answer

Correct answer: Focus, GPU, window size and timing differ

Explanation

Usually the difference is timing or viewport, not features. Use the same settings in CI and locally, and debug with traces.

Further reading

Playwright: Debugging tests ↗

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