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Syncthing uses a web based GUI (currently HTML, Bootstrap 3, JavaScript, and Angular 1.3). This GUI is a bit old, has grown “organically” (that is, without planning or aforethought) for several years, and has multiple issues.

The underlying REST API has some similar issues, in that it also has grown from something small and simple to something large and complex without the benefit of planning.

We would now like to fix these issues with a redesign of both, in concert.

Specifically, we are looking for:

  • A GUI design refresh, taking into account the features that exist today and some limitations that should not persist into the new version. One such limitation is that performance is currently very bad for setups with many devices and/or folders. The refresh should bring both a visually more delightful look and a more well considered organization and some new features that are sorely lacking today, for example a getting-started “wizard” or guide. Some ideas already exist from which to draw inspiration, but none are 100% complete and we appreciate you taking initiative on this point. The GUI should follow modern accessibility standards and be responsive enough to work well on both mobile and desktop.

  • A REST API design refresh, to better support the new GUI but also keeping in mind the needs of external integrations, including other potential GUI implementations. The API should provide easy access to current internal state in the form of events, conveniently allow common actions and configuration changes, and follow a structured plan. The overall architecture remains based on HTTP verbs (GET/POST/PUT/DELETE/PATCH) and uses JSON serialization.

  • An implementation of the GUI refresh in a suitable, modern, environment. We still need to run in a browser, but we are open to suggestions on the front end technologies used (React? Vue.js? Angular? Dart? etc). We expect the implementation to follow best current practices in the chosen framework, whichever it ends up being. Providing a suggestion on this point and a couple of references of previous work is meriting.

  • In concert with the GUI refresh, an implementation of the REST API refresh. This work is done in the existing Syncthing backend, in Go. We expect the GUI and new REST API to evolve together over the course of the project.

  • The work to proceed using the established open source processes in use by the Syncthing project. This means Git, GitHub, and pull requests. Previous open source experience is meriting. We will regardless assist all along the way, both with procedure and code reviews.

To be clear, this is a from-scratch rewrite of the GUI, not a careful piece-by-piece improvement of the existing code. There will be new, exciting bugs and we will need to provide the user with the option to use either the new or the old GUI for quite a while. The new REST API will similarly live beside the old one, for compatibility reasons, for some time.

The GUI and REST API design will be iterated in cooperation with the project maintainers and a more detailed implementation plan created as part of the project. We will also assist with guiding, mentoring, testing and – as required – the implementation of backend API changes.


This is a time-limited grant, not an indefinite employment. We expect the project to require several months, up to maximum about half a year. We will provide a salary or consultancy rate in line with market rates for a junior to mid-level developer. Correspondingly we will factor in time for learning, experimentation and mentoring of a more junior developer.

Eligibility & Application

The grant is available for individuals only, corporations and similar constructions are not eligible. Individuals serving on the board of the Syncthing Foundation or employed by Kastelo Inc. are not eligible.

Submit your application via email to Please include at minimum:

  • Basic information about yourself and your background,
  • Suggestion of front end technologies you would use in this project,
  • Any relevant references to prior work in the area,
  • Your salary or compensation rate requirements.

If you have questions not answered by this brief please see this forum thread where the grant is discussed, or feel free to use the contact email above if you want to ask a question privately.

The evaluation process will include thorough evaluation of the written application as well as personal interviews and consultations with external international reviewers. Evaluation panel assessment will be in complete confidentiality, and will not be disclosed. The decision on the accepted grant application will be taken by the Board of the Syncthing Foundation.


This grant is sponsored financially by Kastelo Inc. Kastelo provides consulting and support services for, among other things, Syncthing.