David Butler, Developer in London, United Kingdom
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David Butler

Verified Expert  in Engineering

Mobile and Full-stack Developer

London, United Kingdom
Toptal Member Since
July 6, 2021

David has nearly two decades of experience as an engineer (C++ and OpenGL), web developer, and mobile app developer. Over the course of his career, he has served as the CTO of a small logistics startup (seven years) and contracted for a large church, improving their website and media offering (two years).


Vertical Future
React, Serverless, Amazon Web Services (AWS), Node.js, Sequelize
St Helen's Bishopsgate
Apple TV, Amazon Echo, Flutter, Node.js, Amazon Web Services (AWS), YouTube API...
ParcelSpace Ltd
Amazon Web Services (AWS), CakePHP, Google APIs, Objective-C, Android, HTML...




Preferred Environment

MacOS, Android Studio, Node.js, PHP, Flutter, Amazon Web Services (AWS), Express.js, Elasticsearch, CakePHP, React

The most amazing...

...project I've worked on was making the API, Android and iOS mobile apps, and admin web app, Bible Matters, for a client with over 10,000 talks and videos.

Work Experience

Software Developer

2021 - PRESENT
Vertical Future
  • Developed an algorithm to produce a production calendar to control and maximize the farm's output, allowing the user to set the crop type, quantity, and harvest date required depending on the available capacity.
  • Built a front end to automate the processes related to growing crops on the farm, such as seeding, germination, growing, and harvesting, from robotic movement of trays of crops to environment control like lighting, humidity, airflow, and irrigation.
  • Created an alerting and messaging system similar to Twitter with mentions and hashtags to allow workers at the farm to communicate with each other effectively.
Technologies: React, Serverless, Amazon Web Services (AWS), Node.js, Sequelize

Contract Software Developer

2018 - 2020
St Helen's Bishopsgate
  • Developed an API to interface with a resource library of 10,000+ talks and videos with a search facility and admin web app for uploading content.
  • Developed mobile apps for users to consume talks, videos, PDFs, and a YouTube live stream.
  • Developed an Apple TV app to play all video content.
  • Developed smart speaker apps (Amazon Echo and Google Assistant) for users to consume and search for audio content.
Technologies: Apple TV, Amazon Echo, Flutter, Node.js, Amazon Web Services (AWS), YouTube API, Vimeo API, iOS, HTML, JavaScript, Mobile Development, REST APIs, AWS Lambda, Dart


2009 - 2016
ParcelSpace Ltd
  • Developed a multi-channel platform—web, iOS, and mobile—for users to be able to add tracking numbers for parcels, view their status, and interface with couriers to communicate delivery preferences.
  • Built an algorithm to optimize courier routes given address postcodes and delivery time slots.
  • Created interfaces to gather tracking information from 20+ different couriers via their API and website.
Technologies: Amazon Web Services (AWS), CakePHP, Google APIs, Objective-C, Android, HTML, JavaScript, Bootstrap, Mobile Development, REST APIs

Software Engineer

2003 - 2008
XPI Simulation
  • Developed a physics model for a driving simulator with realistic suspension, acceleration, and braking for learner drivers and drivers of heavy good vehicles.
  • Developed realistic artificially intelligent traffic to mimic the behavior of surrounding cars whilst driving a virtual car; e.g. lane-changing, obeying traffic lights.
  • Made an engine that could create 3D models from terrain data with low polygon meshes for the ground, buildings, and roads.
Technologies: C++, OpenGL, 3D Graphics

Bible Matters

An app that allows users to access a database of over 10,000 Bible-teaching resources. I made the app with Flutter, API with Node.js and Express.js, and search functionality using Elasticsearch and Logstash. I also made a React web app for admins to upload content to the database and YouTube and Vimeo using their APIs, and I used AWS for transcribing audio and video content.


A web app to make hosting Q&A sessions much easier. It allows event organizers to receive questions from their audiences via text message (using the Nexmo API). Multiple admins can organize incoming questions on their own devices and see changes reflected on all devices (using socket.io).


A Flutter app with Google, Facebook, and Apple sign-in allows users to see books available within their church community and list their own books with a barcode scanner so others can view and borrow books.


A job board for churches that allows them to post jobs so that job-seekers can view available posts and make applications. It uses structured data for SEO, NextJS for the front end, Node.js for the back end, Google Maps API for displaying posts on a map, and Stripe API for payments.
1998 - 2002

Master's Degree in Engineering

Cambridge University - Cambridge, UK


REST APIs, Node.js, Google APIs, React, YouTube API, Vimeo API, OpenGL, Socket.IO, Nexmo, Stripe API


Android Studio, Logstash, Sequelize


Flutter, Express.js, CakePHP, Bootstrap, Next.js


Mobile Development


PHP, HTML, JavaScript, Dart, Objective-C, C++


Amazon Web Services (AWS), Android, iOS, Firebase, AWS Lambda, Apple TV


Elasticsearch, MySQL


Computer Vision, Medical Imaging, Electrical Engineering, 3D Graphics, Amazon Echo, Serverless

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