Create traffic with custom matching rules

Enable Autoresponder

In the Autoresponder tab, check Enable automatic responses.

Compose Autoresponder Rules

At the bottom of the Autoresponder tab, under the Rule Editor:

1. Type a match rule in the top field.
2. Type an action string in the bottom field.

When Enable automatic responses is checked, Fiddler Classic will undertake the action if a captured request URI matches the match rule.