Jekyll2026-06-04T13:52:25+02:00/feed.xmlInterface Refactoring CatalogThe Interface Refactoring Catalog is a collection of interface and other architectural refactorings.Slice 3 and 4 Workshopped and Published at EuroPLoP 20252026-05-28T00:00:00+02:002026-05-28T00:00:00+02:00/news/final-refactorings-workshoppedFor last year’s EuroPLoP writer’s workshops, we submitted two papers to have the final ten refactorings of our interface refactoring catalog workshopped. Both papers have now bee published by Springer Nature under Creative Commons licences:

Feedback on the papers was very positive, leading to interesting discussions. Participants appreciated the papers’ clear structure, detailed explanations of the refactorings and practical examples. They also considered the refactorings to be relevant and applicable to real-world scenarios.

See the publications page of this website for direct links to all papers and related publications. We hope that we considered all the feedback we received and that the refactorings are now even more useful for practitioners and researchers alike.

]]>More Refactorings Workshopped and Published (EuroPLoP24)2024-10-07T00:00:00+02:002024-10-07T00:00:00+02:00/news/more-refactorings-workshoppedWe submitted another seven interface refactorings to this year’s EuroPLoP writer’s workshop. Starting from stakeholder concerns and API design smells was seen to be useful, and the detailed guidance by example appreciated. The carefully chosen names for the refactorings were particularly appreciated for their readability, and the extensive references and footnotes will provide a rich source for their own work. One participant even suggested that the refactorings should be published as a book, with more introduction and context for newcomers. Again, we received a lot of helpful and constructive feedback on how to improve the refactorings and their presentation.

The open-access paper “Pattern-oriented API Refactoring: Addressing Design Smells and Stakeholder Concerns”, to appear in the ACM Digital Library, is available for download via the publications page of this website. We hope that we considered all the feedback we received and that the refactorings are now even more useful for practitioners and researchers alike.

]]>API Design Patterns Adoption and Refactoring Catalog Update2024-07-05T00:00:00+02:002024-07-05T00:00:00+02:00/news/patterns-adoption-refactorings-updateWe have been busy with our Interface Refactoring Catalog. We present the next seven refactorings in Workshop B of EuroPLoP 2024 taking place this week. The first eight interface refactorings were workshopped at EuroPLoP 2023; see our trip report.

The patterns that serve as targets of many of our refactorings are being used in industry and academia. A news item on the API Design Patterns website provides more information.

Our API design patterns book won the “Best Publication Award” 2023/2024 at their university OST – Eastern Switzerland University of Applied Sciences. The jury praised the book for its practical relevance and international impact. We are very proud of this peer recognition!

]]>Refactorings Workshopped at EuroPLoP232023-12-08T00:00:00+01:002023-12-08T00:00:00+01:00/news/refactorings-workshoppedWe submitted eight interface refactorings to this year’s EuroPLoP writer’s workshop. The paper was well received, and we received a lot of helpful and constructive feedback on how to improve it. The overall impression was that it was well written, the figures helped with understanding, and the examples were well chosen and explained. See Mirko’s blog post for more details.

The open-access paper is available for download here.

]]>API Design Pattern of the Week2023-10-26T00:00:00+02:002023-10-26T00:00:00+02:00/news/api-design-pattern-of-the-weekThe API Design Pattern of the Week series is a collection of articles introducing the API design patterns featured in the Patterns for API Design book. The series is published on LinkedIn and Medium. A Medium article provides an overview of the series.

]]>API Design Patterns Book Published2022-11-17T00:00:00+01:002022-11-17T00:00:00+01:00/news/patterns-book-publishedThe API design patterns featured in many of the refactorings in this catalog form the core of the book called “Patterns for API Design: Simplifying Integration with Loosely Coupled Message Exchanges”, published by the Addison-Wesley Signature series editor Vaughn Vernon on Twitter and LinkedIn.

The book features 44 patterns as well as an introduction to API fundamentals and a domain model for APIs. Six decision narratives guide through the conceptual level of API design, identifying 29 recurring decisions with options and criteria. It applies the patterns to three cases, the fictitious Lakeside Mutual microservices scenario as well as two real-world projects that have been running in productions for a long time. The book also contains an introduction to the Microservice Domain Specific Language (MDSL) that we used to illustrate many of our refactorings. A pattern eligibility cheat sheet is available as well.

Patterns for API Design Cover Image

“Patterns for API Design” is available at Amazon.com, InformIT and other bookstores.

]]>Refactorings implemented in MDSL Tools2022-02-03T00:00:00+01:002022-02-03T00:00:00+01:00/news/refactorings-implemented-in-mdslThe latest MDSL Tools implement most refactorings described in this catalog. They are also available through the MDSL Web Tools, a Web application to transform API specifications written in MDSL and generate Open API and other interface descriptions from them. The following screenshot shows the user interface to apply the Introduce Pagination refactoring:

The source code is freely available at GitHub. See the MDSL documentation on Transformations Related to Patterns and Refactorings for details.

]]>Done for 20212021-12-13T00:00:00+01:002021-12-13T00:00:00+01:00/news/seventh-slice-releasedThe final four API “refactorings” (for this year) are now published online. Unlike the previously provided ones, they affect service level agreements and desired evolution qualities rather than the endpoint design and the message structures (for the most part):

API providers and customers are often in opposing positions when making decisions about API longevity and development. For example, providers might want to increase their customer base while at the same time minimizing the number of different versions they have to run and maintain in production. An individual customer whose use case is covered by the API may not want to be forced to upgrade to new API versions. In such cases, it helps if the provider clearly states their API guarantees. If they have to be adjusted, advice can be found in our new Tighten Evolution Strategy and Relax Evolution Strategy refactorings.

One possible outcome could be that the API will be offered in several versions, with the provider introducing an explicit Version Identifier so that clients can choose which version to use. Depending on API changes, introducing a Version Mediator can (temporarily) hide API changes from clients by introducing a mediator that maps the old API calls and their request- and response messages to new ones.

]]>Slice 6 available online2021-11-29T00:00:00+01:002021-11-29T00:00:00+01:00/news/sixth-slice-releasedThree new API refactorings are now published online:

With today’s release, the previously published Add Wish List gets an alternative refactoring: Add Wish Template. If a plain list that enumerates the desired response data structure elements is not flexible enough, the Wish Template pattern offers a richer alternative where clients can express their wishes in a complex data structure. The new Rename Representation Element refactoring completes the Rename series of Rename Endpoint and Rename Operation. Finally, Merge Operations reverts Split Operation and is eligible when two (or more) operations should be collapsed into a single one.

]]>Fifth Slice of API Refactorings Released2021-11-01T00:00:00+01:002021-11-01T00:00:00+01:00/news/fifth-slice-releasedIn today’s release, we are happy to present you three new API refactorings:

Make Request Conditional is concerned with speeding up the communication between API client and provider by not re-sending data the client already has. This can be done by refactoring an API operation to the Conditional Request pattern. The other two refactorings in this release, Rename Endpoint and Split Operation, aim at improving the maintainability of an API, specifically learnability, understandability, and evolvability.

We also updated several of the previously published refactorings substantially to incorporate feedback and to consolidate the stakeholder concerns and smell sections across refactorings. For example, Introduce Pagination was significantly expanded with more “Hints and Pitfalls to Avoid”, contributed by Andrei Furda.

]]>