ISO 8583 vs Name / Value Pairs | Payment Gateway Integration Architecture

It is very important to choose the right payment gateway integration design pattern while developing a payment gateway. This is important because it can impact transaction success rate directly (click here to see why). For online card not present transactions, a name/value or key/value pair based messaging format is considered best for payment gateways because it can help in following ways:

A name value pair based message will look like (just an example):

AccessCode = '100GFTJ',
Amount = 10000,
TransactionType = 'AUTH'
Locale = 'en',
MerchTxnRef = 'myorderid01',
MerchantId = 'mymerchantId',
OrderInfo = 'my order description',
ReturnURL = 'RETURN URL of MERCHANT WEBSITE',
Version = '1'
Note: There can be many other fields like above, can depend on transaction type also

1. Loosely coupled because it provides a flexibility in changing client-server contract in future at server end without requiring the existing client to change integration related code
   
   
2. Simplification of the client-server contract because ISO 8583 requires a learning curve and many online merchants may not have that skill or time required to integrate
   
   
3. Similarity to other payment gateways because many big and popular payment gateways are using the same approach. This kind of similarity allows the clients to integrate with your payment gateway without much effort or additional learning curve
   
   
4. Test-ability ease with various scenarios and transaction types, you can run your existing old test cases to validate if the new code will not break any existing clients
   
   
5. Same messaging format with different transaction types, you can keep the URL also same because the client will not be required to change URL for different transaction types. Transaction type can be a name/value pair in the message like TXN_TYPE=AUTH

In case you are developing a payment gateway interface for card present/POS terminal based transactions then ISO 8583 is better because:

1. ISO 8583 is a light weight and compact messaging format, it makes the message size small all POS terminals may not be having a high internet bandwidth and speed to transfer big sized messages to servers
2. A client/merchant will not require a learning curve because offline merchants are provided the POS terminals by the payment gateway company or a technology partner

Click for a quick read about about payment gateway integration for best transaction success rate

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