For the purpose of better collaboration on dependencies between teams, we suggest some methodologies that have proven to be very effective for teams working together over APIs.

Table of contents

  1. MUST Consumers contribute to APIs
  2. SHOULD API Consumers provide interface tests

MUST Consumers contribute to APIs

Teams of APIs are open to contributions of other teams by following the InnerSource culture. API Consumers contribute the following types of code:

  • MUST Documentation
  • MUST Consumer Driven Contract Tests
  • MUST Bug-Reports and Feature-Requests
  • SHOULD Bugfixes in the API
  • SHOULD Simple API Features
  • MAY Complex Features
  • MAY Refactorings

Teams maintaining an API should actively foster collaboration on their API and should therefore actively maintain a consumer community.


  • APIs will eventually become “consumer driven” (see also the API Maturity model).
  • The Design of an API is more consumer oriented and therefore provides a better developer usability and more functionality. This leads to lower costs through higher reuse.
  • Better speed of API Consumer teams and much less waiting times of consumers for a feature. Solves the backlog hibernation and thus reduces Cost of Delay.

SHOULD API Consumers provide interface tests

APIs should allow and engage consumers to provide Consumer Driven Contract Tests. Tests can be provided over a pact broker like the one from or over source code contribution.


  • With consumer tests, API consumers take on responsibility of the changeability and operational stability of APIs.
  • This leads to early end-to-end testing of interfaces between teams. Early discussions between teams often lead to better collaboration, stability and quality.
  • Consumers are motivated to contribute to APIs (CDC is a an important entry-level step for the path to an InnerSource collaboration model).