Netify is a debugging proxy that will allow you to intercept and mutate your requests, like Fiddler or Charles, but it more compact and implemented directly in the Chrome devtools.

• Filter requests for proxy by URL, method or type of resource.
• Redirect request to arbitrary URL.
• Adding, replacing and removing request headers.
• Replacing a request body with text/JSON, Base64 or form data.
• Replacing a response status code.
• Adding, replacing and removing response headers.
• Replacing a response body with a text value, Base64, or file's content.
• Adding an extra response delay
• Cancel requests on the client.
• The above changes can be made according to predefined rules, by script or by making changes to an intercepted request (like breakpoint).

Netify is fully free and open source. You can thank the author by making a small donation