Developer API

Technically-handy accountants—or those hiring savvy programmers—can extend and integrate TaxCycle and DoxCycle into their tax office programs using our flexible API (application programming interface).

What is an API?

An "application programming interface" or API is a set of rules and specifications that allow different software programs to talk to each other. Programmers can write code that accesses an API to facilitate the sharing of data, calculations and other functionality between programs.

Join the Developer Network

You must join our Developer Network to access the API (contact us for pricing). 

This gives you:

  • Access to developer documentation.
  • License to build extensions using the API.
  • Technical support for API implementations.

Using the API

Once built, you can install your creation on computers in your office. 

But, if you want to process a large number of returns or resell your extension, you must apply for a special licensing that includes either a per-return fee or royalty payments. Please contact us for details.

Need inspiration?

Here are a few ideas of how you could extend TaxCycle or DoxCycle or integrate them into your existing programs or your workflow:

  • Add a client intake assistant to help staff ask the right questions during the client interview process.
  • Create an extension to export data and analyze data in Microsoft Excel®.
  • Automatically back-up each file whenever you save the return.
  • Add or hide icons from the ribbon or toolbars for specific users or specific tasks.
  • Use the TaxCycle calculations engine to power calculations in a different piece of software.


  • All extensions are under Windows® User Access Control (UAC), so you can easily control who can enable or launch particular extensions.
  • When you use an extension to attach custom data to any field, form or return, the data remains intact even if the file is opened in a version of TaxCycle that doesn't include the extension.
  • There is no limit the number of extensions you can add to TaxCycle or DoxCycle. So, create what you need to make your practice better.