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Validate Tool

Charles can validate the recorded responses by sending them to the W3C HTML validator, W3C CSS validator and W3C Feed validator.

The validation report is presented in Charles with any warnings or errors linked to the appropriate line in the response source (double-click the line number in the error message to switch to the source view).

Because Charles tests the responses that it records it can test scenarios that aren't easily tested, such as the presentation of error messages after submitting a form.


After validating you can choose responses from the validation result and Repeat them, which repeats the original request and then re-validates the result. This enables you to fix any validation problems and revalidate the page without having to return to the browser.