Application Programming Interfaces (APIs) could greatly facilitate the exchange of data and functionalities between software applications in a flexible, controlled and secure way, especially on the web. Private companies, from startups to enterprises, have been using APIs for several years now, but it is only recently that APIs have seen increased interest in the public sector. API adoption in the public sector faces organisational, technical, legal and economic obstacles, and to overcome these barriers, proposed methods from the private sector and early adopters in the public sector provide a way forward. The available documentation is often sparse, difficult to find and to reuse for new contexts. No past efforts to collect and analyse these resources have been made. To address this shortcoming, this paper describes a landscape analysis in four areas: the main European Commission policy instruments on the adoption of APIs, the available web API standards, a set of European government API strategies and cases, and a list of government proposed methods distilled from more than 3900 documents. Our results reveal that European policy legislation and associated instruments promote, and in some cases mandate, the use of APIs, and that governments’ API strategies in the European Union are rather young but also that there are well known web APIs standards and proposed methods ready to support the digital transformation of governments through rapid, harmonised and successful adoption of APIs.