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Jonathan Pereira for Progress

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Getting Started with Fiddler Everywhere

What is Fiddler Everywhere?

Fiddler Everywhere is a valuable tool for web debugging and monitoring. It logs all the HTTP(S) traffic between the client and the internet. The tool is handy to inspect, debug, mock, and share network requests and responses.

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Along with the primary use of acting as a web debugging proxy, Fiddler Everywhere has capabilities that make it an excellent tool for API development, performance testing, security testing, and even malware analysis.

Fiddler Everywhere just got out of beta and is available on Windows, macOS, and Linux and supports every browser. Additionally, it can also be made to behave as a reverse proxy, thereby allowing you to inspect traffic between mobile devices and the internet.

Get Fiddler Everywhere

Head over to the Fiddler Everywhere site to download it.

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Fiddler Everywhere is available for Windows, macOS, and Linux. Choose the required platform and download and install the setup file.

Getting Started

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Once you open Fiddler Everywhere, you need to create an account. Enter the required details and click on Create New Account. Alternatively, you can sign-in using your Google account.

The first thing you want to do, once you install Fiddler Everywhere is to check and enable the HTTPS traffic capture. Doing this allows you to inspect and debug web traffic, which is transmitted using the HTTPS protocol, which is quickly becoming the default standard for web development.

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To do this, click on the gear icon on the top right corner. The Setting pop-up will show. In the HTTP(S) menu, click on the Trust root certificate button. Your system will request your system login credentials. After you enter and authenticate yourself, Fiddler Everywhere will automatically complete the process. Make sure to click on the checkbox next to Capture HTTPS traffic.

If you face issues with the root certificate, you can try importing and trusting it manually.

Navigating Fiddler Everywhere

You are now inside Fiddler Everywhere. You can see the default view divided into two major sections – the column on the left displays the web sessions and the column on the right have the Traffic Inspector. The sidebar displays the saved sessions and requests.

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Before you start recording the traffic, you need to make sure that you turn on the toggle in the Live Traffic tab. The tab will display (Capturing) if it is working fine. You can click the toggle again to pause the recording. The tab will display (Paused) when it is not capturing.

Live Traffic

Now you can open any browser and enter the URL you want to inspect. As soon as you hit enter in the browser, you will see the web sessions getting displayed in Fiddler Everywhere.

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The tool provides many insights regarding each session at a glance. For example, you can see the filetype denoted next to the request number. You can see the status code of the request and the protocol used. The host server and the URL slug of the request are also displayed. You can also see information about the request method, response size, content type, and caching. Interestingly, the process from where the request originated is also displayed – for example, browser, desktop app, etc.

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To make things simpler, you can click on the ellipsis in the menu bar and set filters for each tab and view only the required sessions.

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You can right-click any session and save, remove, comment, and mark the session. Additionally, you can also share the session with others by just entering the email address.

Traffic Inspectors

If you want to scrutinize an individual request, you can select the request by clicking on it and see the details in the Inspectors tab on the right. The Inspectors tab displays two panes – the top pane shows the information on the request, and the bottom pane highlights the response.

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In the request pane, you can see all the headers which contain the information sent to the servers like the host name, user-agent, encoding status, and even the cookies. You can view the form data and cookie data, or you can check the text, JSON, and XML used in the request, if any.

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In the response pane, you can view the response headers received from the server, including the status code, access controls, and even the content length. The body of the response is available as text, JSON, or XML. If the response is an image, it is available in the image tab. Interestingly, the entire response is available as a live web page in the web tab.

Auto Responder

The Auto Responder feature is one of the most loved features of Fiddler Everywhere. You can find this feature in the tab next to the Inspectors. The feature allows the developer to mock responses, without actually transmitting the request to a live server.

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You can create a new rule with a match condition and an action to be performed. The term can be a host name, or the URL, or even the file type. If you want to target an URL specifically, you can also set the condition to require an exact match.

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The corresponding action which needs to be executed, in the event of a match, has to be provided. This action could be another URL or a filename or a redirect request. This feature can also help set breakpoints, delay (to imitate network latency), rest the connection, and even close the connection altogether.


The composer feature — next to the “Web Sessions” tab — allows you to modify and send requests to the server. Additionally, you can create your requests and execute it with Fiddler Everywhere.

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To modify an existing request, you can right-click on the request in the “Web Sessions” tab and select the Composer option. The request will automatically get loaded in the Composer tab. Similarly, you can create a new request in the Composer tab directly.

In the Composer tab, you need to select the appropriate HTTP method, enter the request URL, the headers, and the request body. You can click on Execute to send the request to the server or click on Save to save it. Fiddler Everywhere supports all the available HTTP request methods.

Start debugging

Now that you know about Fiddler Everywhere, it is time to put the tool to the test and see how it mystically makes debugging simpler. Head over to the Fiddler Everywhere documentation to get more information about the features. If, at any point, you feel stuck or are faced with an issue, feel free to reach out to the live Fiddler Everywhere community.

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