In this demonstration, we present the main features of WebProtege, a free, opensource, cloud-based OWL ontology editor that supports simultaneous collaborative editing for geographically distributed users. WebProtege is available for general purpose use at https://webprotege.stanford.edu, where it hosts over 55,000 OWL ontology projects and over 42,500 user accounts. The software is open-source and all source code is available on GitHub1. WebProtege 3.0 builds on the success of previous versions but features a new modern interface and new features for collaboration and review. This demonstration, at the ISWC2018 posters and demos session will enable attendees to see the latest features as well as providing them with an opportunity to interact with, and provide feedback to, the WebProtege developers. We discuss the main features here.
WebProtege is essentially a \Google docs" for editing ontologies. Users access \projects" that are collections of OWL ontologies augmented with a change history, and issues/comments. WebProtege provides a default user-interface that supports lightweight ontology editing, for ontologies that more or less t within the OWL2EL pro le. However, it can also be con gured for editing ontologies that require full-blown OWL 2 axioms and class expressions.
Ontology Editing Figure 1 shows the main editing interface, which provides the familiar tabbed look and feel that is common to all desktop versions of Protege. The classes tab is shown here, which comprises four resizable views: (Class Hierarchy, Class Description, Comments and Project Feed). Users can add, remove and customize the layout of views on a tab and the state of the user-interface is automatically persisted for each user in the context of a project.
In contrast to previous versions, WebProtege 3.0 uses proper URL routing, meaning that entities, such as classes, properties and individuals, and the tabs (or pages) that display them, are bookmark-able links that can be shared with people.
WebProtege allows ontology edits to be seen by all users as they take place. However, it is possible to set up a project so that users may only view or comment on a project for cases where there is a core group of editors and a larger group of commenters/reviewers.
Collaborative Features Besides collaborative ontology editing functionality, WebProtege also allows users to comment on a project and create issues in the form of threaded comments. Comments sit outside of an ontology but pertain to speci c entities in an ontology. They are formatted in Markdown and can contain links to any entities contained in the signature of the ontology as well as GitHub style @user mentions. Discussion threads of comments for a given entity can be seen on the right-hand side of Figure 1 in the Comments view. The number of threads is also displayed next to entity names in the various entity hierarchies (left hand side of Figure 1). Threads can be created and closed as issues are opened and then dealt with by ontology editors. Figure 2 shows a global view of the comments manager that is available in the default interface.
When comments are posted, project participants are noti ed via email (left inset in Figure 2). Emails contain the body of the comment and clickable links that take user directly to the comment in a browser window. WebProtege also provides integration with Slack 2 and makes it possible to associate a Slack Web
hook3 with a project so that comments are posted to a Slack channel for external noti cation. Slack users are able to click on links in their Slack clients in order to view the comment directly in WebProtege (right inset in Figure 2).
In addition to comment threads, which can be used for adding review comments to a project, WebProtege also allows entities to be \tagged" with badges that can be de ned for a project. Figure 1 shows various tags in the class hierarchy that have been added as part of the review process. Tags and comments usually go hand-in-hand. Entities with speci c tags can also be searched for in the search dialog.
Change Tracking and Project History One of the key features of WebProtege is that all ontology changes are tracked and grouped into revisions. Revisions are based on atomic user-interface operations and it is possible to revert a single revision. Figure 3 shows an example of the history of a project. Changes can also be viewed/ ltered by entity, so that the entire history for an entity description (both logical and non-logical) can be examined. Labels for revisions are automatically generated based on the ontology changes in a revision. In the full-blown OWL 2 editing interface (not shown here) it is possible to group a set of changes into a commit, which can then have a commit message assigned to it. It is also possible to download the set of ontologies in a given revision.
Integration with Third Party Applications WebProtege does not have a traditional \drop-in" plugin mechanism like the desktop version of Protege does. However, going forward, we intend to facilitate integration with third-party applications via Webhooks and a Web-API. As of now, third-party applications can be noti ed of the changes to a project by adding an event Webhook to a project. JSON formatted messages are posted to the URL associated with the Webhook when changes in the associated project occur. We expect that this functionality will be used for lose coupling with third-party applications in the same way that GitHub and Slack can integrate with other applications. 3
WebProtege is developed by the Protege group at Stanford Center for Biomedical Informatics Research. It is under active development and we welcome feedback from the Semantic Web community in order to guide future development directions. This work is supported by Grant GM121724 from the National Institute of General Medical Sciences at the United States National Institutes of Health.