Joinup continues here with a periodical survey of remarkable EUPL distributed software. As a licence, the EUPL is widely used across Europe by institutions and business bodies.

The National Bank of Belgium (NBB) has published its RESTful API design guide under the terms of the EUPL licence.

That guide serves as the current standard for the creation of all current Web APIs within the bank. It is an important design document for bank software development because it regroups all the choices that have been made and those serve as a set of rules for our development teams and could possibly become a model or template for developments made outside.

A design guide for APIs is useful because there is, at this point in time, no clearly winning industry standard. There are many design choices to make at high level design (pagination? filtering? search? sorting?) as well as in the detailed design (page=2? offset=10? version in the URL or in a header? etc.).

When there are many options to choose from, development teams can argue forever about the best solution for each use case and the guide contributes to avoid such waste of time and to improve standardisation, which is key for developers’ productivity and ease of integration between applications.

This is the reason why, while preparing for the development of their own Web APIs, the National Bank decided to create and share with the whole community of bank developers a comprehensive design guide, covering all current and known future needs.

For more information: https://github.com/NationalBankBelgium/REST-API-Design-Guide/wiki