XML and XSLT used to be a very popular choice for integration transmission. However, this format proved to be messy and complex even with XSD in place. Then, JSON format comes around with the resurgence of JavaScript and REST service. It quickly overtakes XML as the preferred choice of integration format. This puts us into challenging mode as we move to convert XML to JSON.
Your Stack Setup
Historically, the usage of applications is directly linked to the type of integration format used. JSON is very geared towards web languages like JavaScript, Python, PHP and Nodejs. In contrast, XML favored Java and Dot Net languages. Thus, you will find difficulty for your legacy system to consume JSON. Even database is split for CLOB to XML. There is newer database like unstructured or NoSQL database for JSON. Therefore, a consideration of architecture changes may be required to leverage the advantage of integration format like JSON.
Your Endpoints
If you do not have budget and time to overhaul your architecture, you may consider focusing on your endpoints and gateway. It is common to setup integration gateway to manage the translation of XML to JSON. This provides backward compatibility to your legacy architecture. In another words, you gain more time to progressively upgrade your stack. The good part is that these integration gateway can serve as a command post to manage your endpoints.
The switch from XML to JSON is a time consuming effort. If you do not have legacy system with XML, you may want to consider having a technology stack that favors JSON. However, those with legacy and XML integration may want to lower risk with the setup of integration gateway to manage your endpoints and translation of XML to JSON.
Danny Kwok 