Ashley Nelson-Hornstein and I built an app for hanging at WWDC. It took 5 weeks to build. It’s called Beacon, and you can get it on the App Store today.

Beacon is a way to signal to your friends that you’re down to hang out. You can set up an event, and your friends will be able to see those events, and let you know that they want to come. Beacon answers questions like “Who’s free?” “Who likes persian food?”, “We have 2 spots for dinner, and who would want to come?” without the messiness of having to text your entire address book. Each event has a big chat room for organizing, and honestly, goofing around in those chat rooms has been some of the most fun of the beta. Beacon is, at its heart, a very social app.

Ashley and I did a ton of work in these few weeks, trying to get this app from concept to production. I never built an app this fast before, and it’s been an exhilarating ride. In addition to being a stellar dev, Ashley’s got a great eye for the holes in the product and the user loop, which let us tighten up the experience before putting the app in the hands of all of our friends. This project absolutely wouldn’t have worked without her.

Linda Dong also contributed a considerable amount of design work, giving the app life and personality. Before her touch, the “design” was the output of two developers, and you can imagine what a horror show that was.

From a technical perspective, one of the things I’m most excited about is the server side of this project. Chris and I got to talk about this on the last episode of Fatal Error season 2 (Patreon link). Beacon finally gave me the chance to build an application for the server using Swift. We chose Vapor for the framework, purely for the quality of support (mostly a friendly Slack channel) and the size of the community using it.

Swift on the server is a budding project. Builds are slow, test targets are hard to set up, there’s no Xcode (which means no autocompletion or command/option-clicking), Foundation isn’t complete, there’s almost no library support, documentation is god-awful, and everything is changing extremely quickly. Nevertheless, it’s fun as hell to write Swift for the server, and I don’t regret the decision. I think it’s most comparable to writing Swift 1 or 1.1 in a production iOS app. Potentially a problematic decision, but the language was so fun that everyone who did it had no complaints. I think in 2 or 3 years, Swift on the server will be where Swift in the client is now, and that will be a great time indeed.

I’ve written web apps in Node, Rails, and various PHP frameworks, and while it’s possible to take advantage of their dynamically typed features for certain patterns, I often felt like I was programming without a safety net. I felt forced to write tests to make sure that various code paths were getting hit and the right methods were being called.

With Swift on the server, you get all the Swift niceties you’re used to: enums, generics, protocols, sequences, and everything else. All of the other tiny pieces of knowledge of Swift that you’ve built up over the last weeks and months are valid and useful.

A few scattered thoughts on Swift on the server:

  • Because you have a type system, building up little abstractions is much easier, and you can change those abstractions without worrying that protocol conformances down the line will be broken. Optionals are excellent. It’s so nice to know that you have something. For example, in the Event model, I have a non-optional User called organizer, and I have total confidence that through any code path in the app, if I have an event, I will have an organizer.
  • I definitely want Linux support for Sourcery. There’s a lot of boilerplate in model code on the server (sometimes even more than the client) and Sourcery would help with that pain a lot.
  • Because everything in Vapor is synchronous, I rewrote my networking library to simply return a value (or throw) for each request. This makes writing network code so simple, and I find it quite a shame that we can’t take advantage of this on the client as well. I hold out hope that Swift’s async/await implementation will be the answer to some of these woes.

We don’t know if Beacon is a viable product for the broader market, but we think it’ll be a lot of fun at WWDC and we look forward to organizing lots of ad hoc events with all of you awesome people. Find me on the app, and let’s hang out.