POST/checkout/sign-in

Initiate Hosted Payment Page checkout

Redirects customer to MerchantE Hosted Payment Page for checkout. This endpoint accepts form POST data to initiate the payment process.

The customer will be presented with options to:

Checkout as guest (limited view of Hosted Payments)
Create a payment account
Log in to existing payment account

Request Body

Content type: application/x-www-form-urlencoded

Required1 field

profile_idstring

Merchant Identifier (mandatory). Routes the customer specifically to your payment page.

maxLength=20

Others4 fields

payment_amountstring

The amount of the transaction. Only necessary if you have the Custom Amount flag turned off, since in that scenario the payment amount will be sent across from your website to Hosted Payments.

**Important**: If you do not send the amount when the Custom Amount flag is turned off, a hardcoded $0.00 amount will be sent when the customer navigates to the Hosted Payment Page and the customer will not be able to proceed with payment.

format=numeric · maxLength=12

invoice_numberstring

Custom Invoice Number field. Only necessary if you intend on sending an Invoice Number to Hosted Payments. If not, this will automatically be generated once the transaction is processed successfully.

format=alphanumeric · maxLength=17

client_reference_numberstring

Custom Reference Number. Only necessary if you intend on sending a client reference number from your side to Hosted Payments. If not, this will automatically be generated once the transaction is processed successfully.

format=alphanumeric · maxLength=96

transaction_keystring

MD5 hash for request validation when Security Code is enabled.

**Calculation**: MD5(Profile Key + Security Code + Transaction Amount)

The Profile Key is a security code generated by MerchantE. Required only when Security Code security feature is enabled in merchant settings.

Responses

302

Redirect to Hosted Payment Page

400

Invalid request - missing required fields or invalid transaction_key

Code samples

Copy-paste ready code in your preferred language to integrate the Hosted Payment Page.

Form POST

Copy/paste friendly

API call

curl -X POST "https://cert.hostedpayments.merchante.com/hpp/checkout/sign-in" \
  -H "Content-Type: application/x-www-form-urlencoded" \
  --data-urlencode "profile_id=12345678901234567890" \
  --data-urlencode "payment_amount=500.00" \
  --data-urlencode "invoice_number=INV-2023-001" \
  --data-urlencode "client_reference_number=REF-12345" \
  --data-urlencode "transaction_key=5d41402abc4b2a76b9719d911017c592"