Capture a Flutter app's HTTP traffic.

Step by step.

1. 1

   Install Cloak Proxy and trust its certificate

   Download Cloak Proxy (free, no account) and open it. In the orange banner, click Install & Trust… and confirm with your Mac password. The certificate is made on your Mac and is unique to your install.

2. 2

   Add the file to your project

   Open Proxy › Device & Runtime Setup…, choose Flutter, click Save to Project… and pick the folder with pubspec.yaml. Cloak Proxy writes lib/cloak_proxy_overrides.dart, with the certificate inside it.

3. 3

   Call it from main()

   Call install() before anything makes a request.

   import 'cloak_proxy_overrides.dart';
   
   void main() {
     CloakProxyOverrides.install();
     runApp(const MyApp());
   }

4. 4

   Run with the proxy's address

   install() does nothing until the run passes the address. On the iOS Simulator or macOS it's 127.0.0.1:9090; from the Android emulator, 10.0.2.2:9090; from a phone on Wi‑Fi, your Mac's address, with Allow other devices to connect on.

   flutter run --dart-define=CLOAK_PROXY=127.0.0.1:9090

5. 5

   Decrypt your API's host

   Right-click a request from it in the traffic list and choose Enable SSL Proxying for the host, or add api.example.com in Cloak Proxy › Settings… › SSL Proxying. Make the request again and its headers and body show in the inspector.

Every option, screenshot and error message is in the docs:Flutter, Android.