Designing a Digital Membership Card Backend in .NET with IoT Access Control

Need Help With My Project
1

Hi everyone,

I’m currently building a membership card system using ASP.NET Core as the backend and ESP32 devices for access control. The goal is to allow members to check in using a QR-based digital membership card [link to external system removed by moderator], which gets validated through a .NET API, and then log the entry in real time.

What I’ve implemented so far:

  • Created member registration & management system in .NET
  • Generated unique QR codes for each member
  • Built REST API for validating member ID
  • ESP32 successfully connects to WiFi and communicates with Blynk
  • Blynk dashboard shows basic device status

Current Issues / Challenges:

  1. I’m unsure about the most secure way for ESP32 to validate QR data with the .NET API (token-based auth vs API key?).
  2. There is slight latency (2–3 seconds) during validation, and I want to optimize it.
  3. Not sure whether to directly call my backend API from ESP32 or use Blynk HTTP API/webhooks as an intermediary.
  4. Looking for best practices to prevent QR duplication or misuse.

I’m not promoting any product — just trying to design a scalable and secure IoT-based membership access system.

2

@shatavia this looks very much like a spam post to promote the digital membership card system that you say you aren’t promoting.
I’m giving you the benefit of the doubt, but I’ve removed the external link you posted. Please don’t link that site again, otherwise this topic will be deleted any you will be blocked from this forum.

Pete.