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CfP: ESWSA: Workshop on empirical studies of Web service architectures

Stefan Tilkov,

ESWSA: Workshop on empirical studies of Web service architectures (the REST–SOAP debate in numbers) in conjunction with OOPSLA 2008

The recent rapid growth in size and capability of distributed computing systems has heralded new types of software architectures, among them the messaging paradigm championed by Web Services and the distributed hypermedia model upheld by the Web. Currently these two competing styles – known as SOAP and RESTful – are used, but little is known about the real-world engineering characteristics of each style, though each has an active camp of campaigners. The known comparisons focus on sometimes abstract architectural principles, and there is little empirical information in the public domain from specific system implementation experience.

Only one piece of empirical data regarding this debate is available to date. It comes from Amazon. Jeff Barr, quoted by Tim O’Reilly, noted that 85% of Web services requests at Amazon are HTTP-based, or RESTful. That was in April 2003.

The ongoing conflict between the two groups is often called the “REST-SOAP debate”. Yet actual debates, organized for example during conferences, have not been conclusive, because they typically fail to convince the proponents of the competing style. Rather than arguing over abstract concepts, this workshop will address the merits of each style based on empirical experience how systems work in practice.

GOALS OF THIS WORKSHOP The workshop will present empirical work on RESTful and SOAP-based Web Services. We are seeking papers that present empirical engineering evidence regarding specific aspects of both kinds of services. This evidence will be the starting point of the discussion during the workshop that aims to:

  • Identify what is known empirically about building RESTful and SOAP services;
  • Discuss the empirical results to see how widely they apply;
  • Confirm or rebuke abstract claims with empirical evidence; and
  • Identify questions for further study.

Workshop submissions should focus on one of the following types of empirical studies.

Firstly, we are soliciting empirical studies or comparisons of SOAP and RESTful Web services in the context of:

  • Publicly accessible services
  • Cross-Organization Integration (B2B), or inter-enterprise services
  • Enterprise Application Integration (EAI), or intra-enterprise services
  • Non-functional requirements of services (e.g. security, reliability, crash recovery)

Second, studies of the REST architectural style, e.g.

  • How closely does the Web follow the principles of REST?
  • How many Web services claiming to be RESTful follow the principles of REST?

Good sources of arguments regarding the REST-SOAP debate are

  • RESTwiki,
  • Paul Prescod’s paper, “Roots of the REST-SOAP debate,” XML 2002.
  • “RESTful Web services” book by Leonard Richardson and Sam Ruby
  • Web services-related tracks at QCon conferences


We are seeking short papers (up to 6 pages, 9pt font, in ACM format). A submission must pose an empirical question related to Web services, present some data that addresses the question and interpret the results. Submissions will be judged based on soundness of methods, quality of analysis, as well as relevance of the empirical results to the REST-SOAP debate. They will be reviewed by Program Committee members, who are industry and academic experts in the area of Web services.

Submissions will be accepted through the EasyChair submission system available from

Authors of accepted papers will be notified by September 2nd (in time to take advantage of OOPSLA’s early registration discount). Authors will have an opportunity to update their submissions with the reviewers’ feedback until September 20th, 2008. The reviewed submissions will be featured in OOPSLA Companion 2008 and in the ACM’s Digital Library. Note that at least one author of the submitted paper must be present at the workshop to present it.


  • ESWSA paper submission deadline: August 3, 2008
  • Notification of acceptance/rejection: September 2, 2008
  • OOPSLA’s early registration deadline: September 11, 2008
  • ESWSA Workshop: Oct 19th or 20th, 2008


The workshop will run over an entire day’s session at OOPSLA 2008. Morning session: paper presentations (20 mins per paper + 10 mins for questions) Afternoon session: more presentations plus a panel discussion of invited experts


  • Munawar Hafiz, University of Illinois
  • Paul Adamczyk, University of Illinois
  • Jim Webber, ThoughtWorks


  • Mark Baker, Coactus Consulting
  • Raj Balasubramanian, IBM
  • Chris Ferris, IBM
  • Ralph E Johnson, University of Illinois
  • Mark Little, Redhat
  • Steve Loughran, HP
  • Mark Nottingham, Yahoo
  • Savas Parastatidis, Microsoft
  • Ian Robinson, ThoughtWorks
  • Halvard Skogsrud, ThoughtWorks
  • Stefan Tilkov, innoQ
  • Paul Watson, Newcastle University
  • Sanjiva Weerawarana, WSO2


  • Jim Webber, ThoughtWorks
  • Sanjiva Weerawarana, WSO2
  • Kyle Brown, IBM
  • Brian Foote, Industrial Logic
  • Paul Adamczyk, University of Illinois

For more information about the workshop please visit or contact the organizers.