2nd International Workshop on API Usage and Evolution

WAPI will be held on June 2, 2018, co-located with the 40th International Conference on Software Engineering (ICSE 2018) in Gothenburg, Sweden.

Follow us on Twitter @wapi2018, spread the word with #wapi18, and contact the organizers!

To the website of WAPI 2017.


Session 1: Opening & Keynote

Session Chairs
Sarah Nadi and Raffi Khatchadourian

9:00 - 9:15
Workshop Opening & Introductions
9:15 - 10:30
“The Changing Landscape of Refactoring Research in the Last Decade”
Workshop Keynote by Danny Dig (Oregon State University)
Abstract: In the last decade refactoring research has seen exponential growth. I will attempt to map this vast landscape and the advances that the community has made by answering questions such as who does what, when, where, why, and how. I will muse on some of the factors contributing to the growth of the field, the adoption of research into industry, and the lessons that we learned along this journey. This will inspire and equip you so that you can make a difference, with people who make a difference, at a time when it makes a difference.
See the slides.
10:30 - 11
Coffee Break

Session 2: API Evolution

Session Chair
Sebastian Proksch

11:00 - 11:20
“Non-Atomic Refactoring and Software Sustainability”
by Titus Winters (Google)
See the slides.
11:20 - 11:40
“On Software Modernisation due to Library Obsolescence”
by Simos Gerasimou, Maria Kechagia, Dimitris Kolovos, Richard Paige, and Georgios Gousios (University of York, Delft University of Technology)
11:40 - 12:00
“Exploring API/Client Co-Evolution”
by Anna Maria Eilertsen, Anya Helene Bagge (University of Bergen)
See the slides and the code.
12:00 - 12:20
“Discovering API Usability Problems at Scale”
by Emerson Murphy-Hill, Caitlin Sadowski, Andrew Head, John Daughtry, Andrew Macvean, Ciera Jaspan, and Collin Winter (North Carolina State University, Google, University of California Berkeley)
See the slides.
12:20 - 12:30
Discussion of presented topics
12:30 - 2:00
Lunch Break

Session 3: API Learning & Analysis

Session Chair
Jürgen Cito

2:00 - 2:45
“Web APIs - Challenges, Design Points, and Research Opportunities”
Invited talk by Erik Wittern (IBM T.J. Watson Research Center)
Abstract: Web APIs provide programmatic, network-based access to remote data or functionalities. Applications, for example, use the Google Places API to learn about nearby establishments, use the Twitter, Instagram, or Facebook API to connect users with friends and family, or use the Stripe API to accept end-user payments. Increasingly, applications themselves consist of micro-services that expose their capabilities to one another using web APIs.
In comparison to library APIs, which are a common subject of software engineering research, web APIs present unique challenges - both for providers and consumers - that are arguably much less explored yet. In this talk, we outline the characteristics of web APIs causing these challenges. We discuss relevant design points, both for providers and consumers, and how these design points have been implemented by different web API paradigms in recent years. Throughout the talk, we give examples of our research to address web API-related challenges. Our goal is to inspire WAPI attendees to take on some of the many research opportunities surrounding web APIs.
See the slides.
2:45 - 3:05
“Where Does Google Find API Documentation?”
by Christoph Treude, Maurício Aniche (The University of Adelaide, Delft University of Technology)
See the data here or here.
3:05 - 3:25
“Extending Existing Inference Tools to Mine Dynamic APIs”
by Ziyad Alsaeed, Michal Young (University of Oregon)
See the slides.
3:25 - 03:30
Discussion of presented topics
3:30 - 4:00
Coffee Break

Session 4: Open Discussion

4:00 - 5:30 Structure of open discussion TBA. Our goal is to ensure concrete outcomes from this workshop.


Call for Papers

Application Programming Interfaces (APIs) are an essential mechanism for software reuse on many levels, such as libraries or web services. However, over the past two decades, many researchers have shown inherent problems with APIs, such as providing useful documentation for proper use, detecting correct usage patterns or wrong usages, and migrating between API versions. While these efforts have advanced the state of the art, most of these problems still exist today. We believe it is time to reflect and compare experiences from different perspectives and to come up with new solutions to the above challenges.

The 2nd International Workshop on API Usage and Evolution (WAPI) provides a venue for researchers and practitioners to come together and discuss the open challenges that API users and designers face. For example, how can we measure the quality of an API? How can we accurately rely on client code for identifying patterns when the rule of ``the majority do it right’’ does not always hold (e.g., in security-related APIs)? What is the best way to present API recommendations and API usages to a developer? The goal of the workshop is to identify the current open challenges in the area and define a roadmap for innovative solutions. Together with all workshop participants, we aim to publish this roadmap as a New Ideas Paper, e.g., in ASE’18, ICSE’19, SANER’19, or FSE’19. Before the workshop, the organizers will derive questions from the accepted papers and ask participants for feedback. This will serve as a framework for workshop discussions. After the workshop, the organizers will draft a respective publication from the results of the discussions and ask participants to contribute to it.


Topics of interest include, but are not limited to:

  • API design
  • API specification/documentation
  • API quality metrics
  • API usage recommendation
  • API misuse detection
  • API maintenance
  • API evolution and migration
  • Evolution of API documentation
  • Leveraging different sources of data to perform/support any of the above tasks
  • Suitable representations for usage patterns
  • User-friendly ways of presenting API and API-usage recommendations to the developer
  • User or designer perspectives of API usage and evolution
  • Negative experiences (what did not work)
  • Identification of open challenges and proposed solutions
  • Transfer of approaches between different types of APIs, such as library APIs or web APIs
  • Synergies between API-research challenges and other research areas

Submission Information

WAPI 2018 invites contributions in the form of 4-page papers from both researchers and practitioners, as well as talk abstracts from practitioners. Submissions can be research papers, practice papers, position papers, or experience reports. All submissions should describe unpublished work and must have been neither previously accepted for publication nor concurrently submitted for review in another journal, book, conference, or workshop. All submission must follow the ACM formatting instructions. Submissions are peer-reviewed and accepted papers will appear in the workshop proceedings. All submissions should be made through EasyChair.

Important Dates

Submissions due
Monday February 5th 2018
Notification to authors
Monday March 5th 2018
Camera-ready copies due
Monday March 19th 2018

The official publication date of the workshop proceedings is the date the proceedings are made available in the ACM Library. This date may be up to two weeks prior to the first day of ICSE 2018. The official publication date affects the deadline for any patent filings related to published work.



Steering Committee

Program Committee

  • Aiko Yamashita, iKnow Solutions Europe
  • Awais Rashid, University of Bristol
  • Christoph Treude, University of Adelaide
  • Collin McMillan, University of Notre Dame
  • Erik Wittern, IBM T.J. Watson Research Center
  • Hidehiko Masuhara, Tokyo Institute of Technology
  • Hyrum Wright, Duolingo
  • Martin Robillard, McGill University
  • Mehdi Bagherzadeh, Oakland University
  • Michael Pradel, Technische Universität Darmstadt
  • Paige Rodeghero, University of Notre Dame
  • Rob Walker, University of Calgary
  • Sebastian Proksch, University of Zurich
  • Shigeru Chiba, University of Tokyo