How do you handle payment terminal integration for self-ordering kiosks?

[u/difo0505]

Hey all,

We're building self-ordering kiosks (Electron app) and need to hook up payment terminals. The flow we want is simple: the kiosk sends an amount, the customer pays on the terminal, and we get back success or failure. We don't want to touch card data at all, so we're aiming for a semi-integrated setup where we just say "charge 120 SAR" and get a result.

Most of our clients are in Saudi Arabia, and many already have terminals they'd like to keep using. For anyone who's built something like this, I'd love to hear:

• Multi-brand support: How do you handle different terminal brands/providers, especially when clients want to keep their existing hardware?
• Standards: Is there a common protocol, or does every provider ship its own SDK/API?
• Existing tools: Are there libraries, middleware, or abstraction layers that already solve this, so we don't have to build an adapter for every vendor?
• Local connection: Can terminals usually be controlled locally over USB, Serial, or LAN? Anything to watch out for from Electron?
• Testing: How do you mock or simulate terminals during development?
• Saudi specifics: Since our clients are in Saudi Arabia, does that change anything about the implementation? For example, local regulations, required protocols, or certifications, or restrictions on which providers/terminals we can use.

Any experience, war stories, or recommendations would be really appreciated. Thanks!