Legacy software systems can be difficult to extend or interact with. By using legacy modernisation, the universally accepted API allows different applications, services and devices to communicate with the legacy systems. In this way, legacy modernization helps with phasing out older systems, while still meeting the business needs.
Legacy modernization perfectly fits in with the API-led connectivity approach which suggests exposing all of your internal systems as reusable APIs. API-led connectivity has three different layers of APIs:
The System APIs unlock the data and services that are available in your back-end systems. These should expose the information in a back-end independent manner. The complexity of the underlying system is hidden from anyone working with the System API.
The Process APIs compose the underlying System APIs into an API layer that focuses around business concepts. An example of this could be orders, aggregating the shipping information and stock system, independent of the back-end system they reside in.
Experience APIs are created for a specific use-case. They expose the data and functionality that is required to complete a project. These APIs make use of the underlying Process APIs that are in place.
Through modern, RESTful APIs, data and functionality from your legacy applications can easily be consumed by different teams that don’t need to have any particular knowledge of that system.