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Some rule modifications made using Requestly may not appear in Chrome’s Network DevTools — even though they are successfully applied in the background.

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Why This Happens

This primarily affects:
  • Modify Response Rule
  • Modify Response Headers Rule
When these rules are applied, Requestly intercepts and modifies the response after it has been received by the browser, but before it’s delivered to the page. However, Chrome DevTools continues to display the original unmodified response because of technical limitations in the browser’s extension APIs. In short, your modifications do take effect, but they won’t be reflected in the Network tab of DevTools.

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How to Confirm That Modifications Are Working

To verify that your rule is working as expected:
  • Follow this guide to validate rule execution in your browser.
  • Check if the application is behaving according to your changes (e.g., modified data is rendered on the page).
  • Use console.log() or inspect values in the page context (e.g., responses received by fetch() or XMLHttpRequest).
  • Add temporary debug markers (e.g., a test field in a JSON response or a custom response header) and verify their usage in the application logic.