Leon Weidauer, Developer and Designer

Black and White Portrait Photo

I'm a freelance developer and designer available for remote work or on location in Berlin, Germany.

I started teaching myself programming at the age of 11 when I got an old 80386 PC and found a BASIC interpreter on it. From there I began a journey over Delphi, VRML and some C to the languages of the web. I started using HTML, CSS and JavaScript in 1998 and have followed web technologies since then: from the arrival of Firefox and Chrome, the first JS frameworks and HTML5 to the advent of the mobile revolution.

I started a formal apprenticeship as a developer in 2007 where I got into backend development and UI design in addition to frontend development. During that time, user experience became very important to me. During most of my projects, I also frequently did design work, both for UI and graphics.

When designing and building applications, I focus on things that benefit the user: accessibility, availability, usability, performance and conserving the user's resources. I strongly believe that technology exists to serve people, not the other way around.


When talking to machines

  • JavaScript
    node.js, React, Redux, Angular, jQuery
  • PHP (Zend Certified Engineer)
    Symfony, Agavi, Zend Framework, Silex
  • Clojure
    Ring, Overtone
  • Ruby
    Sinatra, Rails
    Bootstrap, Foundation, Inuit
  • SQL
  • Minor experience with: Python, C, Java
  • Currently learning or playing with: Rust, Swift

When talking to humans

  • German (native)
  • English (fluent)

Databases, tools, ...

MySQL, Oracle, MSSQL, CouchDB, ElasticSearch, Redis, SQLite, Emacs, Photoshop, Illustrator, Sketch, Xcode, Git, SVN, Vagrant, Puppet, Redmine, JIRA, Github, Gitlab, Docker


Berlin Online Stadtportal GmbH & Co. KG

September 2015 - now, Freelance Developer

  • maintenance and further development of a cross-platform app using Cordova and React
  • consulting on mobile app projects and concepts
  • Frontend and backend development for e-governance applications

Immobilien Scout GmbH

April 2016 - now

  • Frontend development: React, Angular 1
  • Backend development:L node.js, AWS Lambda
  • Operations: Nginx

BCG Digital Ventures

Oktober 2016 - November 2016

  • development of a web client for a car sharing app
  • UI developement with React.js

GSMK Gesellschaft für sichere Mobile Kommunikation mbH

June 2016

  • development of a React/Redux based frontend application for data visualization and analysis

Immmr GmbH

November 2015 - May 2016, Freelance Developer

  • development of a messaging and audio/video call app for web browsers
  • offline-first approach using PouchDB, syncing with CouchDb
  • implementing a complex UI using React and Flux
  • synching data and interoperability with native apps (iOS, Android)

A&B One Digital GmbH

October 2015 - November 2015, Freelance Developer

  • implementation of a responsive website re-design
  • consulting on design for mobile devices

Advertile Mobile GmbH

September - November 2015, Freelance Developer

  • maintenance of an AngularJS 1.x app
  • development of a mobile product landing page
  • strong focus on page loading performance

Berlin Online Stadtportal GmbH & Co. KG

2012 - 2015, Senior Developer

  • design and development of a web UI for a new content management system (HTML5, CSS3, JS)
  • CMS backend development (PHP, ElasticSearch, CouchDB)
  • various web applications as part of http://www.berlin.de
  • teaching/mentoring of an apprentice software technician (Ruby, PHP, JS, HTML, CSS)
  • open source image processing service (node.js)
  • hybrid iOS/Android app using Cordova (HTML, CSS, JS)
  • implementation and maintenance of the company website (Ruby, HTML, CSS, JS)

Exozet Berlin GmbH

2010 - 2012, Developer

  • CMS backend development for video on demand applications (PHP, MySQL)
  • various web portals for public and private TV stations and VoD providers (PHP, HTML, JS, CSS)
  • mobile web frontend development for VoD applications (HTML5, CSS3, JS)
  • deployments and operations on various projects (Linux, Nginx, PHP, MySQL)

iFD AG, Chemnitz

2007-2010, Apprentice/Junior Developer

  • backend development for warehouse management systems (PHP, MSSQL, Oracle, Java, C)
  • design and frontend development for handheld and vehicle mounted touch terminals (HTML, CSS, JS)
  • UX optimisations for various use cases in logistics: one handed operation, outdoors and refrigerated environments, etc.
  • design and frontend development for large wall mounted monitoring displays in warehouses
  • database reports for various warehouse metrics (MSSQL)
  • database and application deployment and operations (Windows Server, MSSQL, IIS, PHP)

Graduated as an IHK certified "Computer Science Expert" (german: "Fachinformatiker") and passed the Zend Certified Engineer exam in 2010.

Education before 2007

  • 2004-2006: studied chemistry at TU Bergakademie Freiberg
  • 2004: abitur with focus on math and chemistry at Lessing Gymnasium Plauen