Firm Banking Integration Flow

The Easy Cash Direct Debit (Firm Banking) process consists of three stages: Authentication → Account Enrollment → Payment.

End-to-End Flow

Customer

Merchant Server

Hecto Financial

11. Payment request

1. Payment request

22. Mobile identity verification request

2. Mobile identity verification request

33. OTP sent via SMS

3. OTP sent via SMS

44. OTP entry

4. OTP entry

55. Identity verification confirmation

5. Identity verification confirmation

66. Account holder name inquiry

6. Account holder name inquiry

77. Account ownership verification (ARS / micro-deposit)

7. Account ownership verification (ARS / micro-deposit)

88. Account enrollment (direct debit registration)

8. Account enrollment (direct debit registration)

99. Payment (direct debit execution)

9. Payment (direct debit execution)

1010. Payment result response

10. Payment result response

NOTE

One-Time Registration

Account enrollment (step 8) is performed only once. For subsequent payments using an already-enrolled account, you can call the payment API directly without repeating the authentication and enrollment steps.

Step 1: Mobile Identity Verification

Verifies the customer's identity using their mobile phone number.

Order	API	Description
1	Mobile identity verification request	Sends OTP to the customer's mobile phone
2	Mobile identity verification confirmation	Validates the OTP entered by the customer

Authentication API Documentation

Mobile Identity Verification Request

Send OTP via SMS

Mobile Identity Verification Confirmation

Validate OTP

Step 2: Account Holder Name Inquiry

After identity verification, verify the account holder's name using the provided name and account details.

API	Description
Account Holder Name Inquiry I	Verifies account holder based on account number
Account Holder Name Inquiry II	Verifies account holder based on account number and additional information
Account Holder Name Inquiry (with amount)	Verifies account holder using micro-transfer method

Account Holder Verification API Documentation

Account Holder Name Inquiry I

Basic account holder verification

Account Holder Name Inquiry II

Account holder verification with additional information

Step 3: Account Ownership Verification

Generate proof of account ownership for direct debit enrollment via ARS or micro-deposit verification.

API	Description
ARS verification request	Places an ARS call to the customer's phone
ARS verification confirmation	Retrieves ARS verification result
Account ownership verification	Confirms account ownership via micro-deposit (1 KRW)

Account Ownership Verification API Documentation

ARS Verification Request

Initiate ARS automated voice verification

ARS Verification Confirmation

Retrieve ARS verification result

Account Ownership Verification

Account ownership confirmation via micro-deposit

Step 4: Account Enrollment (Direct Debit Registration)

Enrolls the verified account under the merchant's customer profile.

Account Management API Documentation

Account Enrollment

Account Cancellation

Cancel an enrolled account

Step 5: Payment (Direct Debit Execution)

Executes a payment using the enrolled account.

Transfer Service API Documentation

Payment

Direct debit payment capture

Payment Void / Refund

Void or refund a payment

Request / Response Structure

All API requests and responses use JSON format.

Request Example

{
  "mchtId": "Merchant ID",
  "ver": "0A19",
  "method": "RA",
  "bizType": "B0",
  "encCd": "23",
  "mchtTrdNo": "ORDER20240101100000",
  "trdDt": "20240101",
  "trdTm": "100000",
  "pktHash": "SHA-256 hash value",
  "trdAmt": "AES-encrypted amount"
}

Success / Failure Indicators

Field	Success	Failure
`outStatCd`	`0021`	`0031`
`outRsltCd`	`0000`	Error code

Parameter validation failure response example

{
  "outStatCd": "0031",
  "outRsltCd": "ST09",
  "outRsltMsg": "Invalid request message"
}

Next Steps

Detailed Documentation by Feature

Authentication Services

Identity verification, account holder inquiry, and account ownership verification APIs

Recurring Billing

Recurring billing key issuance, capture, and cancellation

Inquiry Services

Transaction result, transaction history, and account list inquiry

Need technical support?

Code Samples

HectoFinancial GitHub