FAQ
1. How to obtain the parameters in the header of the v2 API (docs-v2.useepay.com)?
x-merchant-no: MC → Configuration Center → Secret Key Management → First row datax-api-key: MC → Configuration Center → Secret Key Management → OpenApi Secret Key → Private Key (UseePay_SK_xxx)x-app-id: MC → Configuration Center → Secret Key Management → Domain Management → The website domain/APP English name added here is the appId (must be approved before calling the API)2. I have integrated with the v2 API (docs-v2.useepay.com) as instructed, but I am not receiving webhooks. What could be the reason?
【1】MC Backend → Configuration Center → Secret Key Management → RSA Secret Key → UseePay Public Key is not enabled.
【2】The webhook.create API has not been called to create a webhook.
【3】The created webhook does not include the current event.
Example: If the created webhook only includes refund, you will not receive webhooks related to paymentIntent.
3. Request error: x-merchant-no is inconsistent
【1】Each request header carries an
x-merchant-no parameter, e.g., 50001.【2】If the current request carries a parameter that was not created under the same merchant number, the error
x-merchant-no is inconsistent will be returned.POST /api/v1/customer // create customer
Content-Type: application/json
x-merchant-no: merchant-no-001 // customer created by merchant 001
{
"name": "test user",
xxx
}
x-merchant-no is inconsistent
POST /api/v1/payment_intents // create paymentIntent
Content-Type: application/json
x-merchant-no: merchant-no-002 // PaymentIntent created by merchant 002
{
"amount": 100,
"currency": "USD",
"customerId": "cus_create_by_001" // this customer object was created by merchant 001
}Modified at 2026-05-28 10:57:46