Quite a few of us in the Si digital studio are keen cyclists. We noticed a regular topic of conversation though the more we chatted about our cycling experiences—close passes. So, we began to think, how can we help cyclists keep track of close pass hot spots. And Close Pass was born.

Originally a standalone website, Close Pass launched in Autumn 2017 and works by taking crowdsourced data to highlight close pass hot spots in your local area. But, a website isn’t too practical to use if you’re mid-cycle. So we developed our very own Close Pass mobile app for iOS and Android.

Designed and built to be quick and simple to use, the brand new Close Pass app allows cyclists to log their close pass rapidly. Simply move the pin on the map, select the date and time and log your close pass. It’s that simple. The close pass is then highlighted on the map as a hot spot. And if other users experience close passes there too, the hot spot gets bigger. This acts as a way for other cyclists to avoid close pass hot spots.

We launched the Close Pass mobile app in September 2024 after nearly six months design, development and refinement and we’re looking forward to seeing how it takes off in the cycling community.

When it comes to developing mobile apps, there’s a few different ways to go about it. Native apps are built using each operating systems (OS) own programming language. For Android, it’s Kotlin. For iOS, it’s Swift.

The trouble with native app builds is developers end up duplicating lots of code, which then has to be supported post-launch. This means there’s a lot of time and resource spent essentially maintaining two app builds.

Close Pass is built using a framework called React Native. React Native was developed by Meta, and is a universal language used to create apps and software for iOS, Android, Mac and Windows, making it perfect for apps that need to work on multiple platforms.

For Close Pass, using React Native means we don’t have to double up on code, resulting in less for us to maintain in the background. We can code it once and it works across both Android and iOS—which ultimately means less time spent squashing bugs. React Native is also sharable across our own development team, so it’s quick and easy for others to pick up if there’s urgent bugs that need fixing.

Close Pass is written in TypeScript using the React Native framework. Designed and developed by Microsoft, TypeScript is a superset of Java Script. But, compared to Java Script, TypeScript provides more consistency and reliability across the board thanks it’s slightly stricter rules.

Ultimately, the language choice for an app is based on what you’re building. If it’s only being used on one OS, native is probably the way to go. But if you want your app working across various different systems and devices, React Native might be the best option.

Close Pass is a unique idea, built with some unique features. As a map based app, there’s a lot of complexity around pulling in map and location data. We looked at a few options for our mapping system, but we went for Mapbox. Mapbox is a fully customisable mapping system, allowing us to brand up and tailor our maps however we liked. There was only one problem—Mapbox doesn’t currently support React Native.

After a bit of digging around online, we found a solution—a third party, community run version of Mapbox that does support React Native. This actually worked out better than using Mapbox directly. Where it’s community run, there’s a whole host of people on hand to give us support where we need it. And it’s still fully customisable. A win win situation.

With everything digital, there’s always room for growth. We’ve got big plans for Close Pass, like introducing 3D maps to see close pass hot spots in more detail, GPS turn-by-turn navigation for cycling routes, health data and social sharing to name a few. So watch this space, there’s plenty more to come.

If you’re a cyclist, Close Pass is a must-have app. So if you fancy tying Close Pass out, download it on the App Store for iOS or Google Play Store for Android.