"We have seen a huge increase in volume in use of the Open Integration Platform," John Barnes, VP of product management for software at Wolters Kluwer Tax & Accounting, said during this week's CCH Connections conference in Washington D.C.

Barnes said the number of transaction through July exceeded the total for 2015. Transactions include all the times non-CCH software interacts with Axcess. Barnes says the total traffic is up more than 170 percent. Wolters Kluwer also enables third-party software to integrate with Axcess.

Firms often want to tailor Axcess applications for their own way of doing business. The Software Development Kit, licensed to the firms, provides the Application Programming Interfaces, APIs that are pieces of code that enable outside software to work with Axcess, along with the rules for what firms can and cannot do in writing modifications.

Barnes says firms have shown a high-degree of interest in such software integration. "It comes up in almost every conversation," he says.