networking - Change Response from HTTP Request sent by a program -

i have program activate chip racing results. (its piece of hardware).
watch fiddler (sniffing program) in , outgoing traffic pc when connect chip computer.

the program sends following http request:

post http://example.com/index.php http/1.1 accept: */* accept-encoding: gzip, deflate connection: keep-alive content-length: 185 content-type: application/x-www-form-urlencoded host: example.com pragma: no-cache user-agent: someprogram 1.2.3  data==%0d%0aajlfneew-somelongsecretkey-rgaw%3d%3d%0d%0a 

i receive following response:

<?xml version="1.0" encoding="utf-8"?> <message type="3" result="1" txid="someid" activationdate="" availablecredits="732" firstname="john" lastname="doe" email="johndoe@outlook.com" phonenumber="00123445" notification_email="1" notification_text="1"/> 

is possible edit response when programs check availablecredits variable, value 9999 instead of 732.

im working on windows 8 laptop. in advange!

definitely - fiddler allows modify requests , responses adding rules fiddlerscript. citing fiddler documentation:

to make custom changes web requests , responses, use fiddlerscript add rules fiddler's onbeforerequest or onbeforeresponse function. function appropriate depends on objects code uses: onbeforerequest called before each request, , onbeforeresponse called before each response.

so, have add onbeforeresponse logic replacing availablecredits attribute value value desire.