Integration Guide
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Decoupled Flow Integration

The S2S decoupled flow for cards involves the following steps for the redirect experience.

Steps to Integrate

  1. Initiate payment request with PayU
  2. Redirect the customer
  3. Authorize (charge) the Payment
  4. Check the response from PayU

<RegisterMerchantPrerequiste />

📘

Notes:

  • This API is backward compatible and you can continue to the existing integration parameters to process the 3DS 1.0.2 transactions. 
  • If you are using legacy integration of decoupled flow for S2S, refer to Legacy Flow for Server-to-Server.

Step 1: Initiate payment request with PayU

The merchant initiates PayU with the required transaction mandatory or optional parameters. This needs to be a server-to-server curl call request. URL, parameters, and their descriptions. For more information, refer to Cards Decoupled Flow.

<PaymentAPIEnvironment />

Request parameters

Parameter Description Example

<glossary:key>
mandatory

StringMerchant key provided by PayU during onboarding.

<glossary:txnid>
mandatory

StringThe transaction ID is a reference number for a specific order that is generated by the merchant.

amount mandatory

StringThe payment amount for the transaction.

productinfo mandatory

StringA brief description of the product.

firstname mandatory

String The first name of the customer.

Ashish

email
mandatory

StringThe email address of the customer.

phone
mandatory

StringThe phone number of the customer.

pg
mandatory

String The pg parameter determines which payment tabs will be displayed on the PayU page. For cards, 'CC' will be the value.

CC

bankcode mandatory

String Each payment option is identified with a unique bank code at PayU. The merchant must post this parameter with the corresponding payment option’s bank code value in it. For more information, refer to Card Type Codes and Supported Banks for Cards.

AMEX

ccnum
mandatory

String Use 13-19 digit card number for credit/debit cards (15 digits for AMEX, 13-19 for Maestro) and validate with LUHN algorithm. Refer to Card Number Formats and display error message on invalid input.

5123456789012346

ccname mandatory

String This parameter must contain the name on card – as entered by the customer for the transaction.

Ashish Kumar

ccvv
mandatory

String Use 3-digit CVV number for credit/debit cards and 4-digit security code (4DBC/CID) for AMEX cards. Validate with BIN API.

123

ccexpmon mandatory

String This parameter must contain the card’s expiry month – as entered by the user for the transaction. It must always be in 2 digits or in MM format. For months 1-9, this parameter must be appended with 0 – like 01, 02…09. For months 10-12, this parameter must not be appended – It should be 10,11 and 12 respectively.

10

ccexpyr
mandatory

String This parameter must contain the card’s expiry year – as entered by the customer for the transaction. It must be of four digits.

2021

furl
mandatory

StringThe success URL, which is the page PayU will redirect to if the transaction is successful.

surl
mandatory

StringThe Failure URL, which is the page PayU will redirect to if the transaction is failed.

hash
mandatory

StringIt is the hash calculated by the merchant. The hash calculation logic is:
sha512(key|txnid|amount|productinfo|firstname|email|udf1|udf2|udf3|udf4|udf5||||||SALT)

txn_s2s_flow
mandatory

StringThis parameter must be passed with the value as **4 **for Legacy Decoupled flow.

auth_only
mandatory

StringThis parameter must be passed with the value as **1 **for this parameter.

termUrl
mandatory

StringThis parameter must contain the URL which will receive the authentication response from ACS.

authentication_flow
mandatory

StringThis parameter must be passed with value as REDIRECT.

s2s_client_ip
mandatory

StringThis parameter must have the source IP of the customer.

s2s_device_info
mandatory

StringThis parameter must have the customer agent's device.

notifyurl
optional

StringIt is used to send response regarding current transaction to notify about the current transaction done in merchant site.

address1
optional

String The first line of the billing address.
For Fraud Detection: This information is helpful when it comes to issues related to fraud detection and chargebacks. Hence, it is must to provide the correct information.

address2
optional

String The second line of the billing address.

city
optional

String The city where your customer resides as part of the billing address.

state
optional

String The state where your customer resides as part of the billing address,

country
optional

String The country where your customer resides.

zipcode
optional

String Billing address zip code is mandatory for the cardless EMI option.
Character Limit-20

udf1
optional

String User-defined fields (udf) are used to store any information corresponding to a particular transaction. You can use up to five udfs in the post designated as udf1, udf2, udf3, udf4, udf5.

udf2
optional

String User-defined fields (udf) are used to store any information corresponding to a particular transaction. You can use up to five udfs in the post designated as udf1, udf2, udf3, udf4, udf5.

udf3
optional

String User-defined fields (udf) are used to store any information corresponding to a particular transaction.

udf4
optional

String User-defined fields (udf) are used to store any information corresponding to a particular transaction.

udf5
optional

String User-defined fields (udf) are used to store any information corresponding to a particular transaction.

<HashingRequestParameters />

Sample request

curl --location \
 --request \
 POST 'https://secure.payu.in/_payment' --header 'Content-Type: application/x-www-form-urlencoded' \
 --header 'Cookie: PHPSESSID=mj185cifujktpv1igu9tmuoaal; PAYUID=6b0d4cbbe43702a8a938a4d4c546ae01; PHPSESSID=6388ab6306272' \
 --data \
-urlencode 'hash=5e0f040fb08759d621caf04baab4bd893e1d9f5d3edfc2aa42bea00c2ac7140b14b7883028a3b7fc5df6fb728f7542d85c2930c3f3dc4bab6a8b3da1ff33d9fe' --data \
-urlencode 'key=smsplus' --data \
-urlencode 'txnid=payuTestTransaction8169502' --data \
-urlencode 'amount=1.1' --data \
-urlencode 'firstname=Postman' --data \
-urlencode '[email protected]' --data \
-urlencode 'phone=9988776655' --data \
-urlencode 'productinfo=Product Info' --data \
-urlencode 'surl=https://admin.payu.in/test_response' --data \
-urlencode 'furl=https://admin.payu.in/test_response' --data \
-urlencode 'notifyurl=https://admin.payu.in/test_response' --data \
-urlencode 'codurl=https://admin.payu.in/test_response' --data \
-urlencode 'ipurl=https://admin.payu.in/test_response' --data \
-urlencode 'lastname=' --data \
-urlencode 'udf1=' --data \
-urlencode 'udf2=' --data \
-urlencode 'udf3=' --data \
-urlencode 'udf4=' --data \
-urlencode 'udf5=' --data \
-urlencode 'pg=CC' --data \
-urlencode 'bankcode=CC' --data \
-urlencode 'ccnum=XXXXXXXXXXX8006' --data \
-urlencode 'ccname=ASHISH' --data \
-urlencode 'ccvv=XXX' --data \
-urlencode 'ccexpmon=05' --data \
-urlencode 'ccexpyr=2023' --data \
-urlencode 'txn_s2s_flow=4' --data \
-urlencode 'auth_only=1' --data \
-urlencode 'termUrl=https://admin.payu.in/test_response' --data \
-urlencode 'authentication_flow=REDIRECT'

Sample response

📘

Understanding response parameters:

The response for the S2S payment request is not similar to Merchant Hosted or PayU Hosted Checkout. For description of response parameters, refer to Additional Info for Payment APIs.

{
   "metaData": {
      "message": null,
      "referenceId": "00c44a4c8306f9cbe5ecf6133afe08a7",
      "statusCode": null,
      "txnId": "payuTestTransaction447674",
      "txnStatus": "Enrolled",
      "unmappedStatus": "pending"
   },
   "result": {
      "otpPostUrl": "",
      "acsTemplate": "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"
   },
   "binData": {
      "pureS2SSupported": false,
      "issuingBank": "ICICI",
      "category": "creditcard",
      "cardType": "VISA",
      "isDomestic": true
   }
}

Step 2: Redirect the customer

Basis a successful response of the authentication API, you need to redirect the user to the bank page using acsTemplate.  This API specifies the response that is posted to termUrl after the authentication for the transaction has been processed.

📘

Notes:

  • All callbacks POST form data on the merchant’s termUrl that is passed in Initiate Transaction API. 
  • Validation of the response happens on the basis of the hash value being returned in the hash value of the response.

Request parameters

Parameter Description

rawBankData
mandatory

String This parameter contains the raw response that is received from bank after authentication. The response is urlencoded and in query string format.

referenceId
mandatory

String This parameter contains the reference id being returned for the transaction

bankData
mandatory

JSON This parameter contains the JSON string that is to be used for authorization call.This parameter is received in case of successful OTP submission of decoupled transactions.
The postToBank contains messageDigest and pares that is to be posted back for authorization. For more information on the fields in this JSON, refer to bankData JSON Fields Description.

authenticationStatus
mandatory

String This parameter contains the authentication status of the transaction

hash
mandatory

String This parameter contains the calculated hash of the data that is posted to the merchant. For security purpose it is recommended to validate the hash value before consuming the response. The hash calculation logic is:
sha512(authenticationStatus|bankData|rawBankData|referenceId|salt)

bankData JSON fields description

Field Description Applicable for EMV 3DS

cres
mandatory

StringThis field contains the Base64 encoded value received from ACS as part of the authentication response.

Yes

referenceId
mandatory

String This field is returned in case of decoupled flow. This field contains the reference id for the transaction

 

messageDigest
mandatory

String This field is returned in case of decoupled flow. This field contains the MD value being returned by the bank.

 

pares
mandatory

String This field is returned in case of decoupled flow. This field contains the pares being returned by the bank

 

additionalInfo
mandatory

String This field is returned in case of decoupled flow. This field contains the data that is being used for the gateways that do not return pares.

 

authorizationUrl
mandatory

String This integration document assumes that you have opt-ed out for the particular configuration.
The authorization URL in legacy integrations are present basis the config at PayU. Please reach out to [email protected] to know more about.

Sample response

{ 
    “rawBankData” : “”  
    “referenceId”:  “00c44a4c8306f9cbe5ecf6133afe08a7” 
    “bankData” : { 
    "referenceId": "00c44a4c8306f9cbe5ecf6133afe08a7", 
    "messageDigest": "c2e9e456037f033e5cc3d7b6e556189adf41eeabf706844dff70aac91f6b8e73bb1846286c8f99ea768cf38f7c12369c|523727493647950f32684bd6f1ab07aa6474016f", 
    "pares": "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”, 
    "additionalInfo": 
    { 
        "authUdf1": "", 
        "authUdf2": "", 
        "authUdf3": "", 
        "authUdf4": "", 
        "authUdf5": "", 
        "authUdf6": "", 
        "authUdf7": "", 
        "authUdf8": "", 
        "authUdf9": "", 
        "authUdf10": "" 
    } 
}, 
    “authenticationStatus”  :  “success”, 
    “hash” : “664b8ddd1b5b2d1b68abb7eee5ea6e001a02773499ddcd86956ba0833315e7d4e69c641d7b0b3e7590532e21e71936da173f4eda716fc09f83cd1117f0d0c37c”}

Step 3: Authorize (charge) the payment

The authorization request is the final step of transaction processing. This again needs to be an S2S call from the merchant’s server to PayU server.

Request parameters

Post URL: The data to be posted has to be exactly the same as the JSON response received in the authentication response in Step 2. The data must include the following parameters.

Environment

Testhttps://test.payu.in/AuthorizeTransaction.php
Productionhttps://secure.payu.in/AuthorizeTransaction.php
Parameter Description

key
mandatory

String The merchant key is provided by PayU and acts as a unique identifier for a specific merchant account in PayU’s database.

txnid
mandatory

String The transaction ID is the order reference number generated by the merchant to track a particular order. It can be used only once and PayU’s system does not accept a duplicate Transaction ID.

amount
mandatory

String It should contain the payment amount of the particular transaction. The amount must be greater than Rs. 8000 for the cardless EMI option.

hash
mandatory

String It is used to avoid the possibility of transaction tampering. The hash must in the following structure:
valueOf(key)| valueOf(txnid) | valueOf(amount) |valueOf(authentication_info) | valueOf(salt)

authentication_info
mandatory

JSON The JSON value received in the bankData on the Term URL or pass the fields as in the JSON example.

Example for authentication_info JSON

{
   "referenceId": "00c44a4c8306f9cbe5ecf6133afe08a7",
   "cres": "eyJhY3NUcmFuc0lEIjoiODc3OTFjZWUtMjUxNC00MzZjLWJlZDgtYTYzYTg3YmJkZjAxIiwiY2hhbGxlbmdlQ29tcGxldGlvbkluZCI6IlkiLCJtZXNzYWdlVHlwZSI6IkNSZXMiLCJtZXNzYWdlVmVyc2lvbiI6IjIuMS4wIiwidGhyZWVEU1NlcnZlclRyYW5zSUQiOiJkNDFmNjIwMC0wNDM1LTQ5ZWUtYWExMS1mMzY2ZjA2NjFjNmYiLCJ0cmFuc1N0YXR1cyI6IlkifQ==",
   "messageDigest": "",
   "pares": "",
   "additionalInfo": {
      "authUdf1": "",
      "authUdf2": "",
      "authUdf3": "",
      "authUdf4": "",
      "authUdf5": "",
      "authUdf6": "",
      "authUdf7": "",
      "authUdf8": "",
      "authUdf9": "",
      "authUdf10": ""
   }
}

 authentication_info JSON Fields Description

FieldDescriptionApplicable to EMV 3DS
cresThis field contains the Base 64 encoded value received from ACS as part of the authentication responseYes
referenceIdThis field contains the same referenceId which sent in response of the first call 
additionalInfoThis field can be used in the case of schemes where different parameters may need from merchant side. 
messageDigestThis field includes the Base 64 encoding of (sha56 hash of the JSON data (post to server). 
paresThis parameter contains the pares being returned by the bank. 

Step 4: Check the response from PayU

The response from PayU for Merchant Hosted and S2S integration is similar.

Hash validation logic for payment response (Reverse Hashing)

While sending the response, PayU takes the exact same parameters that were sent in the request (in reverse order) to calculate the hash and returns it to you. You must verify the hash and then mark a transaction as a success or failure. This is to make sure the transaction has not tampered within the response.

The order of the parameters is similar to the following code block:

sha512(SALT|status||||||udf5|udf4|udf3|udf2|udf1|email|firstname|productinfo|amount|txnid|key)

Response parameters

The parameters in the response for similar for all S2S flows. For more information, refer to Additional Info for Payment APIs.

Sample response

The formatted JSON response is similar to the following:

{
   "metaData": {
      "message": "No Error",
      "referenceId": "b6035f64240b1862295bc571952cf984",
      "statusCode": "E000",
      "txnId": "payuTestTransaction2746829",
      "unmappedStatus": "success",
      "submitOtp": {
         "status": "success"
      }
   },
   "result": {
      "mihpayid": "15270336226",
      "mode": "CC",
      "status": "success",
      "key": "4wvMqy",
      "txnid": "payuTestTransaction2746829",
      "amount": "1.10",
      "addedon": "2022-06-01 17:39:29",
      "productinfo": "Product Info",
      "firstname": "Postman",
      "lastname": "",
      "address1": "",
      "address2": "",
      "city": "",
      "state": "",
      "country": "",
      "zipcode": "",
      "email": "[email protected]",
      "phone": "9988776655",
      "udf1": "",
      "udf2": "",
      "udf3": "",
      "udf4": "",
      "udf5": "",
      "udf6": "",
      "udf7": "",
      "udf8": "",
      "udf9": "",
      "udf10": "",
      "card_token": "",
      "card_no": "XXXXXXXXXXXX8006",
      "field0": "",
      "field1": "6540854745166970506094",
      "field2": "947167",
      "field3": "1.10",
      "field4": "15270336226",
      "field5": "100",
      "field6": "",
      "field7": "AUTHPOSITIVE",
      "field8": "",
      "field9": "Transaction is Successful",
      "payment_source": "payuPureS2SAuth",
      "PG_TYPE": "CC-PG",
      "error": "E000",
      "error_Message": "No Error",
      "cardToken": "",
      "net_amount_debit": "1.1",
      "discount": "0.00",
      "offer_key": "",
      "offer_availed": "",
      "unmappedstatus": "captured",
      "hash": "cdc409dfd15a842b8d15d6627d0027619882ed800773fa413cef491ae8ff2ef0cdfa654680ba4c8f3567313c6a6b00b94cb3bb5e16bad21d26be01216a69af41",
      "bank_ref_no": "6540854745166970506094",
      "bank_ref_num": "6540854745166970506094",
      "bankcode": "CC",
      "surl": "",
      "curl": "",
      "furl": "",
      "card_hash": "fdb59253e36daf8b3969525ae3799ccb4bb41993a5d2fcaf22737ec3ac8b90ab"
   }
}

Updated about 2 hours ago