Using M5Stack device to monitor NBAD PPC account balance via API

[dason]

Hi all,

I am working on a small finance monitoring project using an M5Stack Core device and I would appreciate some guidance. I have a business PPC account with National Bank of Abu Dhabi in the UAE and I want to display the current account balance on a small desk device in our office.

The idea is simple. The M5Stack unit connects to WiFi, makes a secure HTTPS request to the bank’s API, and then shows the latest balance on the screen so our admin team can quickly check available funds without logging into online banking every time. The bank has provided API documentation for corporate accounts, and I can successfully retrieve the balance using a test script on my laptop with proper authentication and token handling.

The issue starts when I try to implement the same HTTPS request directly on the M5Stack using Arduino framework. The SSL handshake fails intermittently, and sometimes I receive certificate validation errors. I suspect it may be related to memory limitations or root certificate handling on the device. Since this is a PPC account, the connection must remain secure and I cannot bypass certificate verification.

Has anyone here successfully handled secure banking API calls from an M5Stack device? I am particularly interested in how you managed SSL certificates and token refresh securely on an embedded device. Any advice on best practices for this kind of financial API integration would be really helpful.