Knowledge Base Best Practices

Commingling API Versions

In our efforts to provide the best integration experience for our partners, TSYS has released new versions of our API from time to time so that our partners can use our latest and greatest features. Although partners that are currently integrated to our solutions will still be able to utilize legacy APIs, commingling of the different API versions and certifying new features on legacy APIs is not allowed. This is to ensure that our merchants don't experience any issues with their day-to-day processing, while also providing them with the best integrated solution. All API versions are utilizing the same gateway, so merchants will still have access to their existing transaction data as well as all of our reporting functions.

Reasons for these restrictions include:

  • Legacy APIs may be sunset by TSYS with sufficient notice.
  • Legacy versions of our APIs may receive limited or no support.
  • 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 Pay)
    • Line Item Display
    • EMV
    • EBT SNAP and Cash
    • Healthcare (HSA/FSA cards)
    • Loyalty and Offers

Legacy 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 We Recommend: 

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 at for any questions or comments related to upgrading your integration.