Easily get a billing key using the i'mport REST API.

You can use the iโ€™mport REST API to request for a billing key to make a payment request. When you request for a billing key with the customerโ€™s credit card information, the iโ€™mport server calls the PGโ€™s API to get a billing key. The card information is not saved during this process. This method has the following pros/cons:

  • Pros: can customize card registration form.

  • Cons: must specify the Terms of Use and Privacy Policy, PG and credit card companiesโ€™ requirements are strict for this service, and must take precautions to protect personal information.

If you are planning to develop a merchant UI/UX-friendly payment environment, API integration is the right choice.

STEP 01. Accept credit card information

Add input fields for card information as shown below. Create a hidden field to store the customer_uid to send to the server upon form submission. For corporate cards (excluding cards issued under an employeeโ€™s name), enter a 10-digit business registration number for the birth parameter. The following example calls a POST request for /subscription/issue-billing with input values and customer_uid when you click the Pay button.

What is a customer_uid?

It is a unique value specified by the merchant that maps 1:1 with the billing key issued by PG. A unique customer_uid must be created for each card.

Example: If a customer named Hong Gildong requests for a billing key from A card, the customer_uid must be issued for the specified memberโ€™s credit card number.

If you reuse the customer_uid used to get the existing billing key, the existing billing key will be replaced with the new billing key issued on the new card number. (The billing key that maps to the existing card will be deleted.)

Credit card information required for billing key

  • Credit card number
  • Credit card expiration
  • DOB
  • First 2-digits of card password
<form action="{service URL to receive billing key request}" , method="post"> <!--Example:> <div> <label for="card_number">card number XXXX-XXXX-XXXX-XXXX</label> <input id="card_number" type="text" name="card_number" /> </div> <div> <label for="expiry">card expiration YYYY-MM</label> <input id="expiry" type="text" name="expiry" /> </div> <div> <label for="birth">DOB YYMMDD</label> <input id="birth" type="text" name="birth" /> </div> <div> <label for="pwd_2digit">first 2-digits of card password XX</label> <input id="pwd_2digit" type="text" name="pwd_2digit" /> </div> <input hidden type="text" value="gildong_0001_1234" name="customer_uid" /> <input type="submit" value="Pay" /> </form>

STEP 02. Extract card information

Create an API endpoint to extract the card information from the request body. The following is a sample API endpoint that processes a POST request to /subscription/issue-billing.\

// Process POST request to "/subscription/issue-billing""/subscriptions/issue-billing", async (req, res) => { try { const { card_number, // card number expiry, // card expiration birth, // DOB pwd_2digit, // first 2-digits of card password customer_uid, // value that maps 1:1 with card (billing key) } = req.body; // extract card info from req.body } catch (e) { res.status(400).send(e); } });

STEP 03. Request billing key and handle response

Request for a billing key by using the iโ€™mport Get billing key REST API and return a response based on the result code.

// Process POST request to "/subscription/issue-billing""/subscriptions/issue-billing", async (req, res) => { try { const { card_number, // Card number expiry, // Card expiration birth, // Date of birth pwd_2digit, // First 2-digits of card password customer_uid, // Unique ID for each card (billing key) } = req.body; // Get card info from req.body // Get billing key const getToken = await axios({ url: "", method: "post", // POST method headers: { "Content-Type": "application/json" }, // "Content-Type": "application/json" data: { imp_key: "imp_apikey", // REST API key imp_secret: "ekKoeW8RyKuT0zgaZsUtXXTLQ4AhPFW3ZGseDA6bkA5lamv9OqDMnxyeB9wqOsuO9W3Mx9YSJ4dTqJ3f", // REST API Secret }, }); const { access_token } =; // Access token // Get access token const issueBilling = await axios({ url: `${customer_uid}`, method: "post", headers: { Authorization: access_token }, // Add access token to authorization header data: { card_number, // Card number expiry, // Card expiration birth, // Date of birth pwd_2digit, // First 2-digits of card password }, }); const { code, message } =; if (code === 0) { // Billing key request successful res.send({ status: "success", message: "Billing has successfully issued", }); } else { // Billing key request failed res.send({ status: "failed", message }); } } catch (e) { res.status(400).send(e); } });

To use the iโ€™mport REST API, you must first get an access token.

Request billing key and make payment at once

By using the key-in payment REST API/subscribe/payments/onetime, you can get the billing key and make a payment in a single API call.