After the initial startup, Fiddler Everywhere default captures only non-secure traffic (HTTP).

To enable the capturing and decrypting of HTTPS traffic, you need to install the Fiddler root certificate through the HTTPS sub-menu under Settings.

  • Trust root certificate—Installs and trusts the Fiddler root certificate. The option is available only on macOS and Windows. On Linux, you have to export and trust the root certificate manually. After you install the certificate, you are ready to enable the capturing of HTTPS traffic.
  • Capture HTTPS traffic—Defines if Fiddler Everywhere will capture HTTPS traffic or skip it. By default, this option is disabled. Before you enable the capturing of HTTPS traffic, you must trust the Fiddler root certificate.
  • Ignore server certificate errors—Controls whether Fiddler Everywhere will warn you if an HTTPS server presents a certificate that cannot be validated. Do not check this box when surfing the Internet because of a possible spoofing security threat.

    A typical use case for the Ignore server certificate errors option will be certificate validation errors on macOS while trying to access * domains. Use the option to ignore the validation error and continue the debugging process.

  • Advanced Settings—A drop-down menu that provides the following additional options related to the Fiddler root certificate:
    • Export root certificate—A drop-down menu to select a format and export the Fiddler root certificate to the operating system Desktop folder. Some operating systems might not have a default folder named Desktop. In such cases, you must create this folder (~/Desktop for macOS and Linux distributions) to export the certificate successfully. Fiddler Everywhere provides options to export the following formats:
      • Export root certificate(DER/Binary format)—Exports the Fiddler Everywhere trust certificate in binary format as FiddlerRootCertificate.crt.
      • Export root certificate(PEM/ASCII format)—Exports the Fiddler Everywhere trust certificate in ASCII format as FiddlerRootCertificate.pem.
      • Export root certificate(PKCS 12 format)—Exports the Fiddler Everywhere trust certificate in PKCS 12 format as FiddlerRootCertificate.p12.
    • Reset root certificate—Click the button to remove the currently trusted root certificate, generate a new one, and trust it.
    • Remove root certificate—Click the button to remove the currently trusted root certificate from the OS certificate store. As a result, the capturing of HTTPS traffic will be disabled.

The following figure displays the default settings of the HTTPS menu.

default https settings

Inline Notifications

Until the root certificate is trusted, an inline notification will warn you that the system HTTPS capture is disabled. This notification will hide if you use the preconfigured browser-capturing option and will re-appear once you close the active preconfigured browser instance.

inline notification