Quick vocabulary (HMAC, webhook, wallet, rail)
- HMAC.
- Hash-based Message Authentication Code. The cryptographic signature we attach to every webhook so your site can prove the event really came from Qist and not an attacker. You verify it = you accept it; otherwise, drop the request.
- Webhook.
- An HTTP call we send to your site when an event happens (payment received, failed, refunded). You give us a URL, we POST to it.
- USDC wallet (Polygon).
- Blockchain address starting with 0x where your payments land. We stay non-custodial — we never touch the money.
- Payment rail.
- The on-ramp processor your customer picks at checkout (Revolut, Banxa, MoonPay, crypto-direct…). Each rail has its own fees and per-country/BIN approval rate.