UnknownPay Merchant API
UnknownPay is a payment aggregator that lets merchants connect Server-to-Server (S2S) directly from their own server to:
UnknownPay is a payment aggregator that lets merchants connect Server-to-Server (S2S) directly from their own server to:
- Accept deposits from customers via PromptPay QR or bank transfer, credited to your balance automatically once the amount is matched
- Send withdrawals (payouts) from your balance to a destination account you specify
- Receive near real-time status via webhooks — no polling needed
The Portal is for configuration (issuing API keys, setting up webhooks); the S2S API is for real transactions using an API key + HMAC signature. They are separate.
Three things to remember before your first line of code
Every money field on the wire is a baht string with 2 decimals, e.g.
"100.50" — not a number (100.5) and not satang (10050). Sending the wrong unit is a 100× bug.- Money = a baht string with 2 decimals, e.g.
"100.50" - Secrets are show-once — both the API secret and the webhook signing secret. Copy them immediately.
- Sign every request with HMAC-SHA256 (
X-Api-Key+X-Signature+X-Timestamp) — no signature =401