Redirect Flow (Mandate Checkout)

Purpose : After subscription creation, redirect the user to the hosted checkout page.

Request Type : POST
Endpoint : /paymentTransact/V13
URL - https://zaakstaging.zaakpay.com/api/paymentTransact/V13

Request Attributes

These are the request attributes of the redirect UPI Autopay flow.

Fields	DataType	Mandatory	Description
amount	String	Y	Value should be in paisa. Min Value 100 & Max Value 10000000.
bankid	String	N	For Net Banking, ID of selected bank. e.g. SBI
mandateSubscriptionId	String	N	Unique subscription/mandate identifier for recurring transactions. e.g. SUB987654321
buyerAddress	String	N	Max length 100 alphanumeric Street address of the buyer. (Part of billing address)
buyerCity	String	N	Max length 30 alphabet, Min length 3. (Part of billing address).
buyerCountry	String	N	Country of the buyer.
buyerEmail	String	Y	Valid email address of the buyer. Should be unique for each user.
buyerFirstName	String	N	Max length 30, alphanumeric characters, no special characters or dashes.
buyerLastName	String	N	Max length 30, alphanumeric characters, no special characters or dashes. First name and last name cannot be same. Last Name on card.
buyerPhoneNumber	String	N	Buyer’s landline or mobile phone number, numeric only, no dashes, no spaces. e.g. 123456778
buyerPincode	String	N	Buyer’s pin/zip code. Can have numbers, spaces & hyphens (-) only ( Part of billing address ). e.g. 110092
buyerState	String	N	State of the buyer. (Part of billing address). e.g. Delhi
currency	String	Y	Currency Values defined by Zaakpay. e.g. INR
isAutoRedirect	String	N	Value should be True/False.
debitorcredit		N	Values must be netbanking/wallet/upi
bankid	String	N	Value should be bankid. e.g. SBI
merchantIdentifier	String	Y	Zaakpay’s unique alphanumeric merchant identifier. You can get it from Zaakpay dashboard.
merchantIpAddress	String	N	buyer’s IP address as recorded by your website. e.g. 127.0.0.1
mode	String	N	1 digit only, Numeric. Value 1 = Domain check, 0=To skip Domain check.
orderId	String	Y	Merchant's unique transaction identifier. Max Length should be 40 and must be unique per website. Note: Orderid should be an alphanumeric value. eg.ZAAK20170421.
product1Description	String	N	Max length 100. Free text, alphanumeric.
product2Description	String	N	Max length 100. Free text, alphanumeric.
product3Description	String	N	Max length 100. Free text, alphanumeric.
product4Description	String	N	Max length 100. Free text, alphanumeric.
productDescription	String	N	Max length 100. Free text, alphanumeric. Text description of what you are selling. Atleast 1 product description is mandatory to show in the bill on payment page. e.g. name of book, name of mobile etc
productInfo	JSON	N	To show Order Details with Offers on Checkout Page. e.g. productInfo= ""customizationField"":""Cashback"", ""listProduct"":[ ""description"":""Apollo Health Insurance"", ""cost"":""Rs.80,000.00"", ""customizationValue"":""Rs.8,123.00"" ], ""terms"":""Cashback will get credited in MobiKwik Wallet"".
purpose	String	N	1 digit only, Numeric. e.g. Value 0=Service, 1=Goods, 2=Auction, 3=Other
returnUrl	String	N	Url where you want Zaakpay PG to post the response. This must be the domain(or a sub- domain of it).
shipToAddress	String	N	Max length 30, alphanumeric. You may specify this only when buyer’s address is different from shipping address.
shipToCity	String	N	Max length 30, minimum length 3 alphabet. Shipping address city.
shipToCountry	String	N	Shipping address country.
shipToFirstname	String	N	Max length 30, alphanumeric characters, no special characters or dashes.
shipToLastname	String	N	Max length 30, alphanumeric characters, no special characters or dashes.
shipToPhoneNumber	String	N	Shipping address landline or mobile phone number. Numeric only, no dashes,no spaces.
shipToPincode	String	N	Shipping address pin/zip code. Can have Numbers 2-12 digits, Spaces and Hyphens (-)only.
shipToState	String	N	Shipping address state
showMobile	String	N	False:We show the full-fledged version unconditionally. DETECT:We do detection of the user Agent of the browser from which the request is sent & route accordingly. True: Only allowed, if PG represent mobile view. We show the mobile page unconditionally. missing/not sent: Same as DETECT (i.e. We do detection at our end ).
txnDate	String	N	Transaction date in yyyy-mm-dd format. e.g. 1996-04-15
txnType	String	N	Numeric: Zaakpay Checkout will show the tab on the payment page which corresponds to the txnType you provide. e.g. 1-All, 11- Card, 12- Net-Banking, 13- Wallets, 14- UPI, 15 - Only allow Credit Cards, 16 -Only allow Debit Cards, 17 - EZEClick, 18 - ATM+PIN, 19 - MasterPass, 20 - EMI.
paymentOptionTypes	String	N	To display more than one payment options on the Checkout page corresponds to paymentOptionTypes provided. parameter can now have values 1,11,12,13,14,15,16 and be "_" underscore separated. e.g. 11_12.
zpPayOption	String	N	Which Zaakpay Payment Gateway option have you used for this transaction. 1 digit only, numeric default value is 1. e.g. 0=on_zaakpay, 1=button_redirect, 2=widget_redirect, 3=api.
checksum	String	Y	To be calculated on all request parameters that are posted to Zaakpay API.

Mandatory Parameters for Mandate Checkout

While calling /paymentTransact/V8, ensure the following:

Pass mandateSubscriptionId
- mandateSubscriptionId=SUBXXXXX321
Pass Mandate Amount
- Amount must be passed in the amount field.
- This should match the mandate amount defined in the subscription.
Pass Registered Subscription Order ID
- The orderId must be the same as used in Mandate Subscription API.

CheckSum Calculation

For both integrity & data-authenticity verification before sending data to the API. We use an algorithm HMAC SHA-256 to calculate the checksum. Checksum is calculated on all request parameters that is posted to the API. We require data to be posted to Zaakpay server in the NVP (Name-Value Pairs) format.

Sample Request

curl --location 'https://api.zaakpay.com/api/paymentTransact/V13?merchantIdentifier=b19e8XXXXXX406cbd347643XXXXb6b7973&orderId=orderid340&amount=1000&currency=INR&buyerEmail=uttam.test%40mobikwik.com&buyerFirstName=Uttam&buyerLastName=Test&buyerPhoneNumber=9876543210&buyerAddress=Test%20Address&buyerCity=Delhi&buyerState=DL&buyerCountry=India&buyerPincode=110001&productDescription=Mandate%20Payment&returnUrl=https%3A%2F%2Fwebhook.site%2F194f2580-9089-42b2-bfa8-eec71fb50c9e&mandateSubscriptionId=SUB_XXXXXbf9af866&paymentOptionTypes=25_26&debitorcredit=netbanking&bankid=HDFC&v=13&isRestResponse=true&checksum=220277XXXXXbcac4b06e08XXXXae313cf976cXXXfcecdf74887' \
--header 'Cookie: JSESSIONID=342C92324A9766C1E45ED4F23653A120.162.243; JSESSIONID=39D91F9C01935752C761F5B5927E687A.162.243'

Sample Response

amount 	1000
authCode 	NA
bank 	NA
bankErrorCode 	NA
bankErrorReason 	NA
bankRefNum 	NA
bankid 	NA
cardId 	NA
cardScheme 	NA
cardToken 	NA
cardhashid 	NA
checksum 	90a5e95dXXXXb662bdce2f205f9XXXXXcd91189fXX759f213e30d
doRedirect 	false
extra1 	NA
extra2 	NA
orderAmount 	1000
orderId 	orderid340
paymentMethod 	Not Found
paymentMode 	UPI_MANDATE
pgTransId 	ZPXXff4eXXc2133
pgTransTime 	04/21/2026 14:49:54
product1Description 	NA
product2Description 	NA
product3Description 	NA
product4Description 	NA
productDescription 	Mandate Payment
responseCode 	100
responseDescription 	The transaction was completed successfully.
tokenizedCardId 	NA

txnData={
    "merchantIdentifier": "b19eXXXe406cbdXXXXb6b7973",
    "mandateDetails": {
        "isParentMandate": true,
        "parentOrderId": "orderid340"
    },
    "txns": [
        {
            "pgTransId": "ZPXXff4eXXc2133",
            "orderId": "orderid340",
            "cardScheme": "NA",
            "bankErrorCode": "NA",
            "extra2": "NA",
            "extra1": "NA",
            "cardToken": "NA",
            "responseCode": "100",
            "bank": "NA",
            "bankid": "NA",
            "orderAmount": "1000",
            "product1Description": "NA",
            "product4Description": "NA",
            "pgTransTime": "04\/21\/2026 14:49:54",
            "productDescription": "Mandate Payment",
            "amount": "1000",
            "authCode": "NA",
            "paymentMode": "UPI_MANDATE",
            "product3Description": "NA",
            "bankErrorReason": "NA",
            "tokenizedCardId": "NA",
            "doRedirect": "false",
            "responseDescription": "The transaction was completed successfully. ",
            "cardhashid": "NA",
            "cardId": "NA",
            "paymentMethod": "Not Found",
            "product2Description": "NA",
            "bankRefNum": "NA",
            "txnDate": "2026-04-21 14:49:54.419"
        }
    ]
}&checksum=c8d6e812c3dd7*****71e8afeb81d59b91fecc4d81******93cf83f05

Generated Checksum : 220277XXXXXbcac4b06e08XXXXae313cf976cXXXfcecdf74887

Response Checksum

Response Checksum will be calculated on all parameters in the same order as given below. Prepare checksum string by concatenating all param value with ampersand '&' at the end of each value with the parameter name. For Instance, Please refer to below Response Checksum String and Generated Checksum.

merchantIdentifier=b19e8XXXXXX406cbd347643XXXXb6b7973&orderId=orderid340&amount=1000&currency=INR&buyerEmail=uttam.test%40mobikwik.com&buyerFirstName=Uttam&buyerLastName=Test&buyerPhoneNumber=9876543210&buyerAddress=Test%20Address&buyerCity=Delhi&buyerState=DL&buyerCountry=India&buyerPincode=110001&productDescription=Mandate%20Payment&returnUrl=https%3A%2F%2Fwebhook.site%2F194f2580-9089-42b2-bfa8-eec71fb50c9e&mandateSubscriptionId=SUB_XXXXXbf9af866&paymentOptionTypes=25_26&debitorcredit=netbanking&bankid=HDFC&v=13&isRestResponse=true&checksum=220277XXXXXbcac4b06e08XXXXae313cf976cXXXfcecdf74887

220277XXXXXbcac4b06e08XXXXae313cf976cXXXfcecdf74887