I'm James Potter, a maker and software developer from the UK.

This page serves as a chronological archive of my personal and professional projects.


I built a consumer hardware product with my dad. QTIME is a device and mobile app that allows parents to set daily time limits for their kid's games console.

Jun 2017 — present Python Django C

Lokasi creates an automatic visual diary using only your location history.

It uses your past 48-hours of location data recorded by the Moves app and links it to Google Street View imagery.

(Unfortunately it's temporarily offline due to Moves shutting down.)

July 2017 Django Google Street View

Stretch is a bit like Uber. Except that it's free, there is only one vehicle available (a limousine) and it could be literally anywhere in the United States at this moment.

May 2017 React Native Django
The Limo Diaries

My friend Bart and I bought a 28-foot Lincoln stretch limousine and became the first to drive one to all of the lower 48 contiguous states of the United States.

It took us three months, 15000+ miles and three visits to a mechanic.

March — June 2017

Siphon was an experiment in creating a new workflow for mobile app development. We built it on top of the then-brand-new React Native.

  • Instant OTA updates for your apps
  • You could run your app inside our sandbox app in seconds
  • Removed the need to open Xcode / Android Studio
  • Interviewed at Y Combinator
Oct 2015 — Jul 2016 React Native Go Python Django Objective-C Java

I ran an algorithmic trading platform for cryptocurrencies that let you author trading strategies in the browser.

  • Raised seed funding
  • Scaled up to 30+ live trading and backtesting servers
  • Custom trading and backtesting engine
  • Secure sandbox environment for user-supplied Python code
  • It reached $1m+ monthly volumes at its peak
Jan 2014 — Mar 2015 Python Django Javascript Cython Pandas RabbitMQ

GuestSort was a viral guest list and event registration app for iPhone/iPad. GuestSort was a provider of event management and guest list services to corporate clients.

Freelance project.

November 2013 Objective-C
Poster Montage

Poster Montage was an iPad app that let you rotate, arrange and zoom your photos any way you like, to make poster-sized collages.

Side project.

July 2013 Objective-C
Color Scheme for iPhone

Color Scheme lets you extract a palette of colours from any scene. Simply snap a picture or select an existing image from your gallery.

Side project.

July 2012 Objective-C

I spent the summer of 2011 interning at InboxQ, a Y Combinator company based in San Francisco.

I built a native iPhone app to bring their service to mobile. It was my first production app for iPhone.

July 2011 Objective-C
Color Scheme for Android

My first attempt at building a native Android app. Color Scheme lets you extract a palette of colours from any scene. Simply snap a picture or select an existing image from your gallery. 40,000+ downloads.

Side project.

May 2011 Java