jazelevator.com

Mastering MITM Proxy for API Call Debugging on macOS

Written on

Chapter 1: Introduction to MITM Proxy

Debugging API calls is crucial for creating reliable macOS applications. MITM (Man-In-The-Middle) Proxy serves as a robust tool enabling developers to intercept, examine, and modify network traffic. This guide aims to help you set up and utilize MITM Proxy on your Mac for efficient API call debugging.

Here is my other article on How to Debug iOS Apps Using MITM Proxy in 5 Easy Steps. Please check it out! 🥹

Section 1.1: Installation Process

To install, run the following command in the terminal:

brew install mitmproxy

This command installs both MITM Proxy and MITM Web. Remember, your Mac and mobile device must be connected to the same Wi-Fi network.

After installation, type the following command in your terminal:

mitmweb

This will launch the web interface in your default browser, providing a user-friendly environment for inspecting network traffic. At this point, the proxy is listening on port 8080.

Section 1.2: Configuring macOS for MITM Proxy

To capture traffic from your macOS applications, it's necessary to configure your Mac to use MITM Proxy as its proxy server. Follow these steps:

  1. Open System Preferences and select Network.
  2. Choose the network interface in use (e.g., Wi-Fi or Ethernet).
  3. Click on Advanced, then navigate to the Proxies tab.
  4. Check the boxes for Web Proxy (HTTP) and Secure Web Proxy (HTTPS).
  5. Input 127.0.0.1 as the Web Proxy Server and 8080 as the Port.
  6. Click OK, then Apply — [Remember this step; it can be easily overlooked! 😄].

Section 1.3: Installing the MITM Proxy Certificate on macOS

To decode HTTPS traffic, you must install the MITM Proxy certificate on your macOS device. Open MITM Proxy in your browser by navigating to http://mitm.it.

Note: Ensure you have completed all previous steps correctly before opening this site, or it may not load.

  1. Select macOS and download the certificate.
  2. Open the downloaded certificate file, which will launch Keychain Access.
  3. In Keychain Access, add the certificate to the System keychain and set it to Always Trust.

Chapter 2: Debugging API Calls

With everything set up, you can now begin debugging API calls from your macOS applications. Run your application and initiate the API calls you wish to inspect. MITM Proxy will intercept these calls, allowing you to view the details in the interactive interface.

  • Inspect Requests and Responses: Click on a request in the MITM Proxy interface to view detailed information about the request and response, including headers, body, and more.
  • Modify Requests and Responses: Adjust requests and responses in real-time to see how your application reacts to various scenarios.
  • Save and Replay: MITM Proxy enables you to save requests and replay them, which is beneficial for regression testing.

The video titled "Setup mitmproxy on macOS" offers a comprehensive guide on installing and setting up MITM Proxy on macOS. It covers the necessary steps to ensure a smooth installation process.

The second video, "Capture, Analyze and Debug HTTPS traffic with MITMProxy," demonstrates how to effectively capture and analyze network traffic, making it easier to debug API calls and inspect data.

Conclusion

Utilizing MITM Proxy on macOS for debugging API calls grants profound insights into your application's network interactions. By adhering to the outlined steps, you can effectively intercept, analyze, and manipulate network traffic to troubleshoot issues, validate API functionality, and ensure secure data transmissions. MITM Proxy is an essential asset in the toolkit of developers striving to create robust and dependable macOS applications.

Additional Resources