Roman Kryvolapov Engineering Blog

How to set up Charles Proxy for the Android Studio emulator

These steps were tested in early 2023 on Windows 10 with an API 33 emulator, Android Studio 2022.1.1 and Charles Proxy 4.6.3. I wrote them because I could not find up-to-date instructions: the familiar Proxy tab was gone from the settings of the emulator running inside Android Studio, and Charles had reworked its own setup a little. That tab would not help with HTTPS anyway: it sets the emulator proxy, which tunnels HTTPS without decrypting it, while Charles needs the Android system proxy, and that is what the steps below configure.

Proxy

  1. Start Charles Proxy.
  2. Untick Proxy → Windows Proxy (on macOS, macOS Proxy) so that Charles does not intercept all of the computer's traffic.
  3. Find the computer's local network address: Help → Local IP Address, or in the network settings.
  4. In Proxy → Proxy Settings… make sure the port is 8888.
  5. Find the Android SDK: in Android Studio settings, search for "sdk", open Android SDK and copy the path from Android SDK Location. The adb tool is in its platform-tools folder.
  6. Turn the proxy on in the emulator:
Terminal window
C:\Users\<user name>\AppData\Local\Android\Sdk\platform-tools\adb.exe shell settings put global http_proxy <local IP>:8888

You can cd into platform-tools first and then call plain adb. Instead of the local IP you can give the emulator 10.0.2.2 — its fixed address for the computer it runs on, which does not change along with the network.

  1. Charles will show a connection request — accept it.
  2. The session tab will start showing requests, including the emulator's. To keep only the domain you need, right-click it and choose Focus.

To turn the proxy off when you no longer need it:

Terminal window
adb shell settings put global http_proxy :0

The certificate and HTTPS

  1. Open Chrome in the emulator, go to http://chls.pro/ssl and download the certificate.
  2. In the emulator's settings, search for "certificate", open Install certificate (it sits under different menus in different versions) and install the downloaded certificate.
  3. Under Trusted credentials, the User tab should now list the Charles Proxy certificate.
  4. In Charles, select the address you need, right-click it and choose Copy URL, then go to Proxy → SSL Proxying Settings… → Include → Add and add the copied address; the port is optional. After clearing the history, requests to that address will show up as a tree of REST paths.

Important: this way you will only see HTTPS from Chrome. Since Android 7, apps do not trust user-installed certificates by default, so your own app's requests will stay unreadable. To make a debug build trust the Charles certificate, add res/xml/network_security_config.xml to the project:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <debug-overrides>
        <trust-anchors>
            <certificates src="user" />
        </trust-anchors>
    </debug-overrides>
</network-security-config>

and reference it in the manifest:

<application
    android:networkSecurityConfig="@xml/network_security_config"
    ... >

The debug-overrides block applies only to debug builds, so this trust does not reach the release. If the app uses certificate pinning, that has to be switched off for debugging too.

Rewriting requests and responses

There are three ways:

  • Tools → Rewrite… — add the address, create a rule of type Body, tick Response and put the reply you want into Value.
  • Proxy → Breakpoints — the request or response pauses, and you can edit it by hand while it is in flight.
  • Tools → Map Local — a local file is served instead of the server's response.

One last thing: if the router gives the computer a dynamic IP address, it may be different the next time you connect, and the emulator's proxy will need to be set again. The 10.0.2.2 address does not have this problem.