@conference {apiace:2024:icwe,
	title = {How Many Web APIs Evolve Following Semantic Versioning?},
	booktitle = {24th International Conference on Web Engineering (ICWE)},
	year = {2024},
	month = {June},
	publisher = {Springer},
	organization = {Springer},
	address = {Tampere, Finland},
	abstract = {More and more Web APIs use semantic versioning to represent the impact of changes on clients depending on previous versions. Our goal is to provide insights about the extent to which evolving Web APIs align with semantic versioning rules. In this paper we present the results of an empirical study on the descriptions of 3 075 Web APIs, which released at least one new version throughout their history. The APIs descriptions were mined by retrieving 132 909 commits from 2 028 different open source GitHub repositories. We systematically collected and examined 506 273 changes of 195 different types released within 16 053 new API versions. We classified whether each change is likely to break clients or not, and checked whether the corresponding version identifier has been updated following semantic versioning rules. The results indicate that in the best case, only 517 APIs consistently release major upgrades when introducing breaking changes, while 1 970 APIs will not always correctly inform their clients about breaking changes released as part of minor or patch-level upgrades. We also detected 927 APIs which use a backwards-compatible evolution strategy, as they never introduce any breaking change throughout their history.},
	keywords = {API Analytics, API Evolution, Semantic Versioning, Web API},
	doi = {10.1007/978-3-031-62362-2_25},
	url = {https://link.springer.com/chapter/10.1007/978-3-031-62362-2_25},
	author = {Souhaila Serbout and Cesare Pautasso}
}
@article {2022:jwe,
	title = {A Large-scale Empirical Assessment of Web API Size Evolution},
	journal = {Journal of Web Engineering},
	volume = {21},
	year = {2022},
	month = {November},
	pages = {1937{\textendash}1980},
	abstract = {Like any other type of software, also Web Application Programming Interfaces (APIs) evolve over time. In the case of widely used API, introducing changes is never a trivial task, because of the risk of breaking thousands of clients relying on the API. In this paper we conduct an empirical study over a large collection of OpenAPI descriptions obtained by mining open source repositories. We measure the speed at which Web APIs change and how changes affect their size, simply defined as the number of operations. The dataset of API descriptions was collected over a period of one year and includes APIs with histories spanning across up to 7 years of commits. The main finding is that APIs tend to grow, although some do reduce their size, as shown in the case study examples included in the appendix.},
	keywords = {API Evolution},
	doi = {10.13052/jwe1540-9589.2167},
	url = {https://ieeexplore.ieee.org/document/10246943},
	author = {Fabio Di Lauro and Souhaila Serbout and Cesare Pautasso}
}
@conference {apiace:2022:ecsa,
	title = {To deprecate or to simply drop operations? An empirical study on the evolution of a large OpenAPI collection},
	booktitle = {16th European Conference on Software Architecture (ECSA)},
	volume = {13444},
	year = {2022},
	month = {September},
	pages = {38-46},
	publisher = {Springer},
	organization = {Springer},
	address = {Prague, Czech Republic},
	keywords = {API Analytics, API Evolution},
	doi = {doi.org/10.1007/978-3-031-16697-6_3},
	author = {Fabio Di Lauro and Souhaila Serbout and Cesare Pautasso}
}
@conference {2021:icwe:api-evolution,
	title = {Towards Large-scale Empirical Assessment of Web APIs Evolution},
	booktitle = {21st International Conference on Web Engineering (ICWE2021)},
	year = {2021},
	month = {May},
	pages = {124-138},
	publisher = {Springer},
	organization = {Springer},
	address = {Biarritz, France},
	abstract = {Web Application Programming Interfaces (APIs) decouple the internal implementation of a service from its consumers which can reuse and compose them to rapidly build new applications.
Many Web APIs are described with the OpenAPI Specification (OAS). The goal of our research is to check the feasibility of using API descriptions found in public open source repositories to study how APIs evolve over time. To do so, we collected a large dataset of OAS documents by crawling open source repositories, we parsed the corresponding metadata and measured the API size in order to extract a simple model to track the lifecycle of API artifacts and observe common evolution behaviors. Our preliminary results indicate that only a subset of the APIs changes, but as opposed to the expectation that APIs should only grow to maintain backward compatibility we also detected a number of APIs with a more variable history. We also study the stability of API artifacts over time and whether APIs are more or less likely to change as they age.},
	keywords = {API Evolution, OpenAPI, Web API},
	doi = {10.1007/978-3-030-74296-6_10},
	author = {Fabio Di Lauro and Souhaila Serbout and Cesare Pautasso}
}
