[Solved] Clarification on Fiddler Classic commercial use during and after the transition period

[Chenxi]

Hello Fiddler team,

I am writing to request clarification on how commercial use of Fiddler Classic is defined following the licensing change effective 3 August 2026.

We have used Fiddler Classic for many years in software and API testing, troubleshooting, and network traffic analysis. We are currently reviewing legacy deployments and images that may still contain the product and planning the appropriate migration and compliance steps.

Could you please clarify how commercial use is assessed in the following situations?

• Does the presence of Fiddler Classic on an EC2 instance or AMI, by itself, constitute commercial use?

• Or does commercial use apply only when Fiddler Classic is launched and actively used, such as to capture API calls or other network traffic?

• How should an unused legacy AMI that still contains the installation be treated?

• What licensing or compliance steps do you recommend for deployments or images that may still contain Fiddler Classic after 17 September 2026?

A clear explanation of the applicable criteria would help us determine the appropriate migration and compliance steps. Thank you for your assistance. We look forward to your guidance.