The #1 Rule of API Design
I just wrote this article on API design for Elsevier’s SciTech blog. It talks about the importance of hiding implementation details and covers information hiding techniques for C++, Objective-C, and Python, such as the pimpl idiom and class extensions. The article includes a discount code for 40% off my book, in case you’ve been waiting for the price to come down before buying it! Check it out at:
Government recommendations for Web API Design
The US Federal government has published a set of guidelines for government agencies that want to design Web-based APIs. This includes recommendations on authentication, keys, documentation, and code samples; with links to examples of Web APIs in the .gov domain.
Java API Design Checklist
Ferenc Mihaly maintains a blog call the Amiable API where he posts various articles on API design. As part of this blog, he provides a checklist of dos and don’t in API design. The list is focused on the Java programming language, however, most of what Ferenc presents it applicable to other languages too. I really like the bullet list format and the use of verbs to produce a concise yet extensive set of general rules to consider when developing an interface.
Richardson Maturity Model
Martin Fowler wrote about a way to approach RESTful Web APIs developed by Leonard Richardson. This presents 4 successive levels of concepts, from the simple “plain old XML” layer, through the notion of resources, http verbs, and hypermedia controls. Martin does a great job of explaining each of the layers through the use of figures and example XML data.
API Usability Testing at AT&T
Pamela Fox wrote about some great process that AT&T implemented to test the usability of their APIs. They invited several developers to come in and test out their APIs and give feedback on ways they can improve their developer experience. This is a great idea and fantastic way to improve an API based upon actual customer experience:
New eBook on Web API Design
The folk at apigee have distilled everything they’ve learned about Web API design over the last few years into a new free eBook called “Web API Design: Crafting Interfaces that Developers Love.” This collates many of the details from their various blog posts into a single reference, covering topics such as REST, handling errors, versioning, authentication, complementary SDKs, and many others. If you’re writing a Web API for your platform this is a great read.
APIs: A Strategy Guide
A new book on developing Web-based APIs is about to be published called “APIs: A Strategy Guide: Creating Channels with Application Programming Interfaces.” The book is written by Dan Jacobson, Greg Brail, and Dan Woods, who between them have an impressive background in developing real-world Web APIs. The book aims to educate executives and business development teams on the value and strategy for building Web APIs.
Versioning Tips for RESTful API Design
Brian Mulloy at Apigee wrote a short article on versioning for Web APIs where he contrasts three different methods of including versioning information in a URL. These include using a timestamp or version number in the URL path, or accepting a version number as an optional parameter. Brian suggests using a mandatory version number as far left in the URL as possible, and using a whole number instead of dot notation for your versions.
How API Testing Can Help
Bj Rollison wrote an article on API testing in which he talks about the differences between unit, API, and GUI testing. He goes on to describe some of the key benefits of API testing, including: reduced testing costs, improved productivity, and higher functional quality. Bj concludes by talking about the relationship between developers and testers.