Knowledge Base Best Practices

Commingling API Versions

In order to provide the best integration experience for our partners, TSYS has released new API versions from time to time so that its partners can use TSYS' the latest and greatest features. Although partners that are currently integrated to our solutions will still be able to utilize existing APIs, commingling of the various different API versions and certifying new features on existing APIs is not allowed. This is to ensure that our mutual merchants do not experience any issues in the field as well as to provide them with the best integrated solutions. All API versions are utilizing the same Gateway on the back end so merchants will still have access to their existing transaction data as well as all of TSYS' reporting functions.

Reasons for these restrictions:

  • Legacy APIs can be sunsetted by TSYS with sufficient notice
  • Limited or no support may be available for the legacy versions of our APIs.
  • Mixing features among different APIs leads to increased maintenance
  • Crucial updates may only be available in the latest versions of our APIs.
  • Partners can only get access to the latest features/technologies listed below in the current versions of our APIs. For example:
    • NFC (Apple Pay, Google Wallet)
    • QR Code (LevelUp)
    • Line Item Display
    • EMV
    • Loyalty and Offers

Legacy/Old API versions:

  • MerchantWARE Pro
  • MerchantWARE Web Services
  • MerchantWARE 2.0 Client
  • MerchantWARE 2.1 Web Services
  • MerchantWARE 3.0/3.1 Web Services
  • MerchantWARE 4.0 Web Services
  • Transport.WEB v1
  • Transport.WEB v2

What TSYS recommends: 

If you are integrated with any of the APIs listed under the Legacy/Old APIs section above and are looking to add new features or to enhance functionality, it is strongly recommended that you upgrade to the latest versions of the APIs listed below.

Current API versions:

Please reach out to the Certification Engineering team for any questions/comments related to upgrading your integration by contacting