For the purpose of higher reuse, more autonomous clients and «Self Service» of capabilities, it is crucial that APIs are well understandable, documented and easily accessible to other teams and external partners.

Table of contents

  1. MUST APIs are findable
  2. MUST Business capabilities as a Service
  3. MUST Centralized API documentation in English
  4. MUST Define plans driven by the API’s business context

MUST APIs are findable

APIs must be published in the central API Repository, also known as the SBB Developer Portal. APIs must be logically ordered and grouped by business capabilities or domains for better findability. APIs have a unique name and short description which describes the business capabilities in one or two sentences.

API Names

The name of an API must represent the business capability that it provides, focusing on consumers and a wide understandability. Organizational names must not be used for API Names. API Names should be as unique as possible.


  • Better transparency and findability leads to a higher reuse which again leads to lower redundancy and costs.
  • Better findability and documentation leads to a higher collaboration between API consumer and provider.
  • We expect better stability and efficiency in development due to better documentation.

MUST Business capabilities as a Service

For the sake of agility and more speed in development, it is very important that consumers can consume business capabilities over APIs without the need of human interaction. This is especially important for early prototyping, fast ramp-up, mode-2 projects and for creating new partnerships. Usually teams will nevertheless collaborate and talk together before production readyness.

APIs must provide subscription plans and there must be an automated sign-up process. Plans are usually used for distinct pricing and/or access management.

Hint: Every API that is published via API Management (APIM) automatically fulfilles these requirements.


  • Managed APIs provide automated transparency of technical interfaces between teams.
  • We expect a much higher speed and efficiency when implementing new interfaces, which leads to reduced Cost of Delay.

MUST Centralized API documentation in English

API Linting by Zally SBB Ruleset: ApiMetaInformationRule

An API must be documented in English by focusing on API consumers. For a better reuse quota it is crucial that APIs are well documented. Good documentation fulfills the following properties:

  • It describes the business capability in 1-3 sentences.
  • It puts the API in a well understandable context.
  • It provides all important information that a developer needs to consume the API (specification, security, access-codes, …).
  • It is understandable to internal and external developers.

For a better understandability of the technical specifications, there should also be meaningful examples and the possibility to Try-It-Out in a sandbox environment. Cookbooks, blueprints or even public client libraries and code templates help developers consume APIs more efficiently.

Define the language

In a complex business domain, it’s hard to translate everything in another language without losing context. If you chose to define your resources in another language than English, you must provide a glossary with the explanations of the different resources.


A good example for comprehensive documentation is the b2p API.


  • Comprehensive documentation leads to lower costs through higher reuse and better collaboration.
  • Increased understandability also improves development speed and thus reduced Cost of Delay.
  • Documentation in English enables new business models due to a global understandable repository of APIs.

MUST Define plans driven by the API’s business context

API plans in API Management must be designed to meet the clients needs. They must be driven by the API’s business context. Appropriate API plans are well documented and clarify the usage of the API.

Use limited plans only

We highly recommend to use limited plans only in API Management for all APIs and all plans. Plan limits clarify what amount of requests the API backend expects and can handle and therefore significantly improve documentation and understandability of an API. It also improves stability of the API and all it’s clients.


A good example for business context driven plans is the b2p API.


  • Well documented and designed API plans lead to better understandability and thus also a better stability
  • API plans are vital for client management and also for lifecycle management