Nelson Kelem (TheCrab)
Software Developer
South East London, UK
Hire me, am available

I am based in Purley, South East London. I mostly work online so I can live where I love.


Nelson Kelem is a:

  • code optimiser and problem solver or critical thinker
  • software developer and code experimenter (Ruby, JavaScript and Erlang primarily)
  • avid reader of many programming and CS books
  • open source software spirit sharer hoping to make sharing popular
  • an experienced web and iOS app developer and software enthusiast
  • tech-based community organiser (iLinkoln)
  • a dreamer and tinkerer with enterprising leanings
  • a visual-centric software developer


I’m a full stack web developer, with a focus on backend systems. My key skills include among others:

  • HTML, CSS, Adobe Illustrator/Photoshop (2007-present)
  • Ruby and Ruby-on-Rails/Datamapper (2009-present)
  • Vanilla Javascript, JQuery (2009-present) and AngularJS (2013-present)
  • Nodejs and Express framework (2013-present)
  • Objective-C, RubyMotion (2014-present)
  • TDD/BDD I honestly can not remember when I started testing, its one of those things.

Languages:- Ruby is my main go to (OO) language, Nodejs for real-time API’s, Elixir is my current interest for functional language.

I’m an ardent advocate for Open Source dev and a contributor, author of among others:

  • Hanami-FumikiriWIP a JSON Web Token authentication gem for Hanami Web framework
  • Spree-gocardless ‐ a GoCardless extension for Spree Commerce, GC is a UK Direct Debit payment processor making life easy for SME and Sole Traders.

I’ve also contributed to: Spree Commerce and DataMapper 2 among others and currently Hanami Web Framework.


  • Backend development
    • Languages: Ruby, MacRuby, Nodejs
    • Languages with intermediate proficiency: Elixir, Go
    • Frameworks: Rails, Hanami, Roda, Sinatra, Sails, Express
    • Frameworks with intermediate proficiency: Phoenix
  • Frontend development
    • Web HTML5, CSS3, Javascript, Dart, Objective-C
    • Web frameworks BackboneJS, AngularJS, UIKIT CSS, Bootstrap CSS,
    • Mobile frameworks: RubyMotion, Xcode, Ionic
  • Testing suits: TestUnit, RSpec + Capybara

    I prefer using RSpec with Capybara for frontend integration testing in place of Cucumber.

  • Prototyping: Photoshop, Illustrator, Bootstrap and UIKIT CSS
  • Preprocessors Javascript (CoffeeScript and TypeScript), CSS (Sass, Grunt, Gulp)
  • Databases: Postgres, SQLite, MongoDB, RethinkDB
  • Architecture and UML: OS X (macOS), Linux (Ubuntu) and Git

Tech community work

I founded the iLinkoln Digital Meetup Group in Lincoln. And organised the first ever hackday in Lincoln, besides running the group for almost 4 years. I attend a number of hackathons mainly in the UK.

Work experience

My experience is mainly drawn from freelancing work and collaborations on Open Source Software projects. Largely they are backend systems. For the past 5 years I have worked at a digital agency (Safarista Design), where as a senior developer I focused on Ruby and Rails development. Below are some apps I have worked on.

Fullstack Web and API apps

  Project Timelines Technologies Description
1 Bless Africa Tours 2011-2014 Rails 4.2, Postgres, Bootstrap, Javascript, Devise, Google Calendar African Safaris and Mt. Kilimanjaro trekking tours company
2 Enterprise St Helena 2012-2015 Rails 4.2, Elastic Search, Postgres, Bootstrap, Javascript, Forem, Devise commissioned by Government of Saint Helena
3 Fat Pheasant 2010-present Rails 3, Postgres, Javascript, Bootstrap Personal Contacts unified Hotmail, Google, Yahoo and Facebook for when you loose your phone. WIP
4 Lincs Piper 2009-present Rails 4, JQuery + Vanilla Javascript, Vanilla CSS directory like Gumtree. Unfinished personal quest.
5 Property Piper 2011 Sinatra, SQLite, Google maps, Elastic Search Property search engine WIP
6 Rails Piper 2013-present Sinatra, Postgres, Sorcery, Heroku Ruby developers cv posting/search.
7 Waddington Taxis 2013-present Rails 4.2 API, Devise, Backbone JS, PureCSS framework Taxi booking app, dispatch app and driver app thats mobile friendly
8 Paxi Labs 2015-2016 Hanami, Hanami-Fumikiri, Postgres, MongoDB, Google Firebase, Redis, OpenShift hosting, Apple/Google/MapBox Maps Developed a number of API’s plus iOS apps used privately and some awaiting launch in 2016

Mobile apps iOS

  Project Timelines Technologies Description
1 VanMan 2015-2016 iOS, RubyMotion, Objective-C, Apple Maps, Google Firebase, Sails (Nodejs) Help Delivery drivers reduce dead mileage
2 Spota 2015-2016 Sails-JS, Firebase + GeoFire, RubyMotion, OpenShift - Almost like Uber.
3 Spoted 2015-2016 RubyMotion, Apple Maps, CoreLocation The driver-app for accepting jobs booked via Spota
4 Swara 2015-2016 RubyMotion, Stripe, Hanami Mobile card payment app
5 Strop 2015-2016 Rails, RubyMotion, CoreLocation, MongoDB Mobile dating app
6 Kutsh 2013-2016 Stripe, Ionic, Postgres, Rails 4.2 International Mobile payment remittance

I am in the process of writing the Android equivalent of some of the above apps.


Lincoln University — BA Architecture, 2007-2009

Strengths and goals

I can work as software architect or developer. I can also do on-site Ruby on Rails, Hanami web frameworks and frontend web development.

My goal is to help in design and development of better backend and UI strategies and simplify solution architecture by using the best architecture solutions for the task and business strategy.

Please get in touch