Pre-request script of Initiate payment

/* this example is using postman-util-lib library (, copywrited by joolfe and licensed under MIT License:

Copyright (c) 2019 joolfe

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pm.test("Status code should be 200", function () {
	// Delete all enviroment variables
    // Download postman-util-lib library for crypto
	pm.environment.set("pmlib_code", responseBody)

	//setting Basic Auth header for smoother response sample management
	let BasicAuthPlain = pm.environment.get("ClientId") + ":" + pm.environment.get("ClientSecret");
	let BasicAuthEncrypted = CryptoJS.enc.Base64.stringify(CryptoJS.enc.Utf8.parse( BasicAuthPlain));
	pm.environment.set("BasicAuth", "Basic " + BasicAuthEncrypted);
	//console.log(`Encoded value: ${pm.environment.get("BasicAuth")}`);

    // Test to make sure that the private key is valid
    pm.test("Private key should be valid", function () {
        const errorMsg = "Please check your private key (SignaturePrivateKey) that is set in __Set parameters Pre-request script."
        const privateKey = pm.environment.get('SignaturePrivateKey') || '';
        try {
            var sig = new{"alg": "SHA256withRSA"});
            var hash = sig.signString("test");
            var testSignature = CryptoJS.enc.Base64.stringify(CryptoJS.enc.Hex.parse(hash));
        } catch(e) {

After that, you can upload below sample to Pre-request script section.

//*************** PLEASE SET YOUR PARAMETERS BELOW ***************

// Merchant 2048 bit Private Key (Insert your private key here)
    "-----BEGIN RSA PRIVATE KEY-----\n" +
    "MIIEpQIBAAKCAQEAz4geWRDv5Yv2b3PmHjbqtNIZmoMGyqXHCUSd2ms7dktT56Jv\n" +
    "[...]\n" +
    "[...]\n" +
    "[...]\n" +
    "[...]\n" +
    "[...]\n" +
    "ZcMUYN/SsgE+sQ7Wcgny+pSHxOUVfyVlcnmYOTnRyf+1SjhTjZWOj0c=\n" +
    "-----END RSA PRIVATE KEY-----");

pm.environment.set("ClientId",          "ClientId from Dev App properties" );
pm.environment.set("ClientSecret",      "ClientSecret from DevApp properties" );
pm.environment.set("ClientBrandId",     "BrandId from your Merchant profile" );
pm.environment.set("RedirectUrl",       "https://your.callback/url" );

// STAGE endpoints
pm.environment.set("baseUrlBackend",    "api-stage" );
pm.environment.set("baseUrlPublic",     "api2-stage" );

// PROD endpoints
//pm.environment.set("baseUrlBackend",    "api" );
//pm.environment.set("baseUrlPublic",     "api2" );


When you’ll upload Initiate payment API structure, you can add Pre-request script below:

if (pm.environment.get('pmlib_code') == null || pm.environment.get('pmlib_code').length < 100) {
    console.error("Please run __Set parameters script first");
    throw new Error("Please run __Set parameters script first");

// Loading the library

// Get private key and request body hash
const privateKey = pm.environment.get('SignaturePrivateKey') || ''; // RSA 2048 or 4096 bit private key "-----BEGIN RSA PRIVATE KEY-----..." generated locally

const reqMethod = pm.request.method.toString().toLowerCase(); // Get request method POST, GET, etc...
const reqUrl = pm.variables.replaceIn(pm.request.url).toString().toLowerCase().split("//")[1]; // Get URL, fill in Postman variables and remove "https://"
const reqBody = pm.variables.replaceIn(pm.request.body).toString() // Get request body and fill in Postman variables
const reqBodyMinified = reqBody.replace(/\s+/g, ''); // Remove spaces, newlines, etc. from request body

pm.request.body.update(reqBody); // Update request body with postman variables to prevent possible signature issues.

const dataToSign = reqMethod + "|" + reqUrl + "|" + reqBodyMinified;

//console.log('Data to sign: ' + dataToSign)

var sig = new{"alg": "SHA256withRSA"});
var hash = sig.signString(dataToSign);
const signature = CryptoJS.enc.Base64.stringify(CryptoJS.enc.Hex.parse(hash));

pm.environment.set("RequestSignature", signature)
//console.log('Merchant API signature: ' + signature);

And then you can add similar test as below:

if (pm.response.code === 201) {
    var jsonData = JSON.parse(responseBody);

    pm.environment.set("PaymentId", jsonData.payment.paymentId);

If you feel that more help is needed, please contact our support at [email protected] .

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