How to Integrate External QR Code Login into Your Own Platform Using Charles & Apifox

I previously needed to embed a QR code from another platform into our self‑developed system so that users could log in to our platform by scanning that QR code, obtain a WeChat login token via the scanned data, and then use the token to fetch and display WeChat merchant information.

Integrating External Functionality Locally

Below is a step‑by‑step walkthrough of how to capture the external platform’s API traffic, reproduce the scanning flow, and integrate it into a local application.

1. Use the Charles proxy to capture the platform’s API calls, setting appropriate filters at the bottom of the tool.

2. Export the captured request as a cURL command, then import it into Apifox to analyze the API and repeat the request as needed.

3. Organize the API list, map out the request flow, and invoke the APIs from our self‑developed platform to achieve the functionality graft.

This solution can be applied to any scenario that requires parsing and reusing another application’s API. Main tools: Charles + Apifox

Mimicking the WeChat Scan Flow

Assume we have both a mobile app and a web app, and we want the mobile app to scan a QR code to log into the web app.

1. The web app generates a unique code, creates a QR code for it, and sets an expiration time.

2. The web app periodically checks the status of the unique code (e.g., awaiting scan, scanned, confirmed, expired) and updates the UI accordingly.

3. The mobile app scans the QR code, retrieves the unique code, and updates the server with the new status such as “scanned” or “confirmed”.

4. After the mobile app confirms, it updates the user information associated with the unique code; the web app then fetches this information and logs the user in automatically.