I run WiFi for a few hostels using TP-Link Omada controllers. Wanted customers to buy data and check their remaining balance straight from WhatsApp, no need to message me directly. Sounded simple. It was not. Attempt 1: TP-Link's official Open API TP-Link has a real, documented API for this. OAuth2, client credentials mode, the whole thing. I set it up exactly the way their own tutorial says to: created an app, grabbed the Client ID, Client Secret, and Omada ID straight from t...