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Understanding ISO8583 Message Type

Understanding ISO8583 Message Type

The following visual "reveal"(I would say) the meaning and composition of an ISO8583 message type. First bit tells the version of the ISO8583, second defines the class, third is for function to be performed(request/response/etc), and the last one shows origin. See following fig-1.

FIG 1: Message type definitions of each bit.

Here(Mitug) is a resource that helped me a lot to get started, that was referred to me by my friend Syed Kamran. In some places Mitug website doesn't work, atleast a couple of my friends from different locations of the world map reported the website is not opening the page. So for friends who are unable to open the same, rightclick and save as this [PDF] layman's guide to understanding the ISO8583 financial transaction messages.


  1. Anonymous19 November

    I think the last one is not correctly interpreted because 0110 which is a response from Issuer for 0100 sent by Acquirer. Please advise

  2. Last bit always shows the party who "originated" the transaction.

    In your case, the origin(last bit) of the transaction is "Acquirer".

    Don't forget to checkout: http://en.wikipedia.org/wiki/ISO_8583 which concurs, xxx0 -> who began the communication (Acquirer)

  3. Anonymous19 November

    Got it. Thanks