Fiddler Everywhere provides a Rules tab tool, which is a powerful feature that enables you to mock server responses and simulate various real-life scenarios.
You can use the Rule Builder to create rules and automatically trigger a specific request, which meets the criteria set in the rule. To mock a server response, enable the Rules tab, set a rule, and execute the request that will trigger that rule.
To create and test a rule:
- Select the Rules tab and click the Add New Rule button. As a result, the Rule Builder will be opened.
- Enter a descriptive rule name, which will later appear in the Rules Queue.
- Add a condition or a set of conditions to match sessions.
- Add an action or a set of actions to modify the matched sessions.
- Click Save to save and add the created rule in the Rules Queue.
Switch the Live traffic to the Capturing mode.
- If you test with Live Traffic, make sure that you enable the toggle of the main Rules. Open the application in the browser and execute a request that matches the set conditions. The rule is immediately applied to the ongoing captured traffic.
- If you test with saved sessions, select the rule and use the Execute button. The rule is immediately applied to the loaded saved sessions.
The Rules tab can be a powerful ally in testing various complex scenarios without meddling with the server. You can share, import, and export created rules with collaborators to further ease your support, development, and QA processes.