Pattern Index

by Role About

API Description

Which knowledge should be shared between an API provider and its clients? How should this knowledge be documented?

API Key

How can an API provider identify and authenticate clients and their requests?

Aggressive Obsolescence

How can API providers reduce the effort for maintaining an entire API or its parts (such as endpoints, operations, or message representations) with guaranteed service quality levels?

Atomic Parameter

How can simple, unstructured data (such as a number, a string, a Boolean value, or a block of binary data) be exchanged between API client and API provider?

Atomic Parameter List

How can multiple related Atomic Parameters be combined in a representation element so that each of them stays simple, but their relatedness becomes explicit in the API Description and the runtime message exchanges?

Backend Integration

How can distributed applications and their parts, which have been built independently and are deployed separately, exchange data and trigger mutual activity while preserving system-internal conceptual integrity without introducing undesired coupling?

Community API

How can the visibility of and the access to an API be restricted to a closed user group that does not work for a single organizational unit but for multiple legal entities (such as companies, nonprofit/nongovernment organizations, and governments)?

Computation Function

How can a client invoke side-effect-free remote processing on the provider side to have a result calculated from its input?

Conditional Request

How can unnecessary server-side processing and bandwidth usage be avoided when frequently invoking API operations that return rarely changing data?

Context Representation

How can API consumers and providers exchange context information without relying on any particular remoting protocols? How can identity information and quality properties in a request be made visible to related subsequent ones in conversations?

Data Element

How can domain/application-level information be exchanged between API clients and API providers without exposing provider-internal data definitions in the API? How can API client and API provider be decoupled from a data management point of view?

Data Transfer Resource

How can two or more communication participants exchange data without knowing each other, without being available at the same time, and even if the data has already been sent before its recipients became known?

Embedded Entity

How can one avoid sending multiple messages when their receivers require insights about multiple related information elements?

Error Report

How can an API provider inform its clients about communication and processing faults? How can this information be made independent of the underlying communication technologies and platforms (for example, protocol-level headers representing status codes)?

Eternal Lifetime Guarantee

How can a provider support clients that are unable or unwilling to migrate to newer API versions at all?

Experimental Preview

How can providers make the introduction of a new API, or new API version, less risky for their clients and obtain early adopter feedback without having to freeze the API design prematurely?

Frontend Integration

How can client-side end-user interfaces that are physically separated from server-side business logic and data storage be populated and updated with computing results, result sets from searches in data sources, and detailed information about data entities? How can application frontends invoke activities in a backend or upload data to it?

Id Element

How can API elements be distinguished from each other at design time and at runtime? When applying domain-driven design, how can elements of the Published Language be identified?

Information Holder Resource

How can domain data be exposed in an API, but its implementation still be hidden? How can an API expose data entities so that API clients can access and/or modify these entities concurrently without compromising data integrity and quality?

Limited Lifetime Guarantee

How can a provider let clients know for how long they can rely on the published version of an API?

Link Element

How can API endpoints and operations be referenced in request and response message payloads so that they can be called remotely?

Link Lookup Resource

How can message representations refer to other, possibly many and frequently changing, API endpoints and operations without binding the message recipient to the actual addresses of these endpoints?

Linked Information Holder

How can messages be kept small even when an API deals with multiple information elements that reference each other?

Master Data Holder

How can I design an API that provides access to master data that lives for a long time, does not change frequently, and will be referenced from many clients?

Metadata Element

How can messages be enriched with additional information so that receivers can interpret the message content correctly, without having to hardcode assumptions about the data semantics?

Operational Data Holder

How can an API support clients that want to create, read, update, and/or delete instances of domain entities that represent operational data: data that is rather short-lived, changes often during daily business operations, and has many outgoing relations?

Pagination

How can an API provider deliver large sequences of structured data without overwhelming clients?

Parameter Forest

How can multiple Parameter Trees be exposed as request or response payload of an API operation?

Parameter Tree

How can containment relationships be expressed when defining complex representation elements and exchanging such related elements at runtime?

Pricing Plan

How can the API provider meter API service consumption and charge for it?

Processing Resource

How can an API provider allow its clients to trigger an action in it?

Public API

How can an API be made available to an unlimited and/or unknown number of API clients outside the organization that are globally, nationally, and/or regionally distributed?

Rate Limit

How can the API provider prevent API clients from excessive API usage?

Reference Data Holder

How should data that is referenced in many places, lives long, and is immutable for clients be treated in API endpoints? How can such reference data be used in requests to and responses from Processing Resources or Information Holder Resources?

Request Bundle

How can the number of requests and responses be reduced to increase communication efficiency?

Retrieval Operation

How can information available from a remote party (the API provider, that is) be retrieved to satisfy an information need of an end user or to allow further client-side processing?

Semantic Versioning

How can stakeholders compare API versions to detect immediately whether they are compatible?

Service Level Agreement

How can an API client learn about the specific quality-of-service characteristics of an API and its endpoint operations? How can these characteristics, and the consequences of not meeting them, be defined and communicated in a measurable way?

Solution-Internal API

How can access to and usage of an API be limited to an application, for instance, components in the same or another logical layer and/or physical tier?

State Creation Operation

How can an API provider allow its clients to report that something has happened that the provider needs to know about, for instance, to trigger instant or later processing?

State Transition Operation

How can a client initiate a processing action that causes the provider-side application state to change? How can API clients and API providers share the responsibilities required to execute and control business processes and their activities?

Two in Production

How can a provider gradually update an API without breaking existing clients but also without having to maintain a large number of API versions in production?

Version Identifier

How can an API provider indicate its current capabilities as well as the existence of possibly incompatible changes to clients in order to prevent malfunctioning of clients due to undiscovered interpretation errors?

Wish List

How can an API client inform the API provider at runtime about the data it is interested in?

Wish Template

How can an API client inform the API provider about nested data that it is interested in? How can such preferences be expressed flexibly and dynamically?