How to install the sample kit on a web server:

1. Copy PaytmKit folder in document root of your server (like /var/www/html)
2. Open config_paytm.php file from the PaytmKit/lib folder and update the below constant values
   • PAYTM_MERCHANT_KEY – Can be downloaded from the Paytm portal. One time downloadable
   • PAYTM_MERCHANT_MID - MID (Merchant ID) can be collected from Paytm team
   • PAYTM_MERCHANT_WEBSITE - Website name can be collected from Paytm team
3. PaytmKit folder is having following files:
   • TxnTest.php – Testing transaction through Paytm gateway.
   • pgRedirect.php – This file has the logic of checksum generation and passing all required parameters to Paytm PG.
   • pgResponse.php – This file has the logic for processing PG response after the transaction processing.
   • TxnStatus.php – Testing Status Query API

For Offline(Wallet Api) Checksum Utility below are the methods:

1. getChecksumFromString : For generating the checksum
2. verifychecksum_eFromStr : For verifing the checksum

To generate refund checksum in PHP :

1. Create an array with key value pair of following paytm parameters (MID, ORDERID, TXNTYPE, REFUNDAMOUNT, TXNID, REFID)
2. To generate checksum, call the following method. This function returns the checksum as a string. getRefundChecksumFromArray($arrayList, $key, $sort=1)