HTTP - Fiddler

About

Fiddler ¹⁾ is a HTTP Network Analyzer via a forward proxy

How it works

It will install itself as the system HTTP Forward proxy.

How to capture traffic?

from browser

Browsers support the system proxy (ie windows configuration). You have nothing to do to see and capture the request made by browsers.

from your application

You need to configure the proxy to point to Fiddler

Example Java:

On the HTTP library

ProxyOptions fiddler = new ProxyOptions();
fiddler.setHost("127.0.0.1");
fiddler.setPort(8888);
RequestOptions clientRequestOptions = new RequestOptions()
      .setProxyOptions(fiddler)

On the system level

System.setProperty("http.proxyHost", "127.0.0.1");
System.setProperty("https.proxyHost", "127.0.0.1");
System.setProperty("http.proxyPort", "8888");
System.setProperty("https.proxyPort", "8888");
// For the seamless experience in Windows you may consider adding
System.setProperty("javax.net.ssl.trustStoreType","Windows-ROOT");

Example

Support

Error: NET::ERR_CERT_DATE_INVALID

Why ? The issued certificate has expired
Solutions: You need to reset all certificates. Go to Tools > Options > HTTPS > Actions > Reset All Certificates

No traffic captured: Filters?

Be sure that there is no filter in the bottom left corner. If this is the case, a right click will delete it

¹⁾