Edit and replay XHR chrome/firefox etc?

Question

I have been looking for a way to alter a XHR request made in my browser and then replay it again.

Say I have a complete POST request done in my browser, and the only thing I want to change is a small value and then play it again. This would be a lot easier and faster to do directly in the browser.

I have googled a bit around, and haven't found a way to do this in Chrome or Firefox.

Is there some way to do it in either one of those browsers, or maybe another one?

Answer 1

Chrome :

• In the Network panel of devtools, right-click and select Copy as cURL
• Paste / Edit the request, and then send it from a terminal, assuming you have the curl command

See capture :

Alternatively, and in case you need to send the request in the context of a webpage, select "Copy as fetch" and edit-send the content from the javascript console panel.

Firefox :

Firefox allows to edit and resend XHR right from the Network panel. Capture below is from Firefox 36:

Answer 2

Chrome now has Copy as fetch in version 67:

Copy as fetch

Right-click a network request then select Copy > Copy As Fetch to copy the fetch()-equivalent code for that request to your clipboard.

https://developers.google.com/web/updates/2018/04/devtools#fetch

Sample output:

fetch("https://stackoverflow.com/posts/validate-body", {
  credentials: "include",
  headers: {},
  referrer: "https://stackoverflow.com/",
  referrerPolicy: "origin",
  body:
    "body=Chrome+now+has+_Copy+as+fetch_+in+version+67%3A%0A%0A%3E+Copy+as+fetch%0ARight-click+a+network+request+then+select+**Copy+%3E+Copy+As+Fetch**+to+copy+the+%60fetch()%60-equivalent+code+for+that+request+to+your+clipboard.%0A%0A&oldBody=&isQuestion=false",
  method: "POST",
  mode: "cors"
});

The difference is that Copy as cURL will also include all the request headers (such as Cookie and Accept) and is suitable for replaying the request outside of Chrome. The fetch() code is suitable for replaying inside of the same browser.