Johannes Stein, Developer in London, United Kingdom
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Johannes Stein

Verified Expert  in Engineering

Software Engineer and Developer

London, United Kingdom
Toptal Member Since
June 30, 2014

Johannes is a highly skilled software engineer and manager who empowers autonomous teams to build a collaborative engineering culture. He has extensive knowledge of JavaScript, web technologies, and cross-platform development. Johannes is also extremely passionate about open-source software and is proficient in software architecture.


Mobile, Swift, Metabase, Kotlin, Agile Software Development, CTO, Leadership...
Mindful Chef
Agile Software Development, Scrum, Kanban, Ruby, TypeScript, React...
Mindful Chef
Agile Software Development, TypeScript, JavaScript, React, React Native, Redux...




Preferred Environment

Visual Studio Code (VS Code), GitHub

The most amazing...

...code I've written was to solve a complicated linking problem on my own for which no answer was available through Google.

Work Experience

Chief Technology Officer

2023 - 2023
  • Worked as a part of the senior leadership team to transform a tech-enabled company into a tech-driven company.
  • Advocated for data consistency and data-driven decision-making.
  • Initiated, planned, and tracked the development of the Android port of the flagship iOS app.
Technologies: Mobile, Swift, Metabase, Kotlin, Agile Software Development, CTO, Leadership, Amazon Web Services (AWS), Android, iOS, Figma, App Store, REST APIs, Team Leadership, Mobile Development, Git, Third-party APIs, REST, Front-end, NestJS

Head of Engineering

2021 - 2023
Mindful Chef
  • Decreased cycle time by 40% by transforming the approach from "work for squads" into building "squads around work."
  • Built, maintained, and guided the engineering vision for the next three years.
  • Transitioned from a hybrid working environment into a remote-first culture.
  • Introduced, managed, and mentored engineering managers within the digital department.
Technologies: Agile Software Development, Scrum, Kanban, Ruby, TypeScript, React, React Native, Ruby on Rails (RoR), Engineering Management, Heroku, Budget Management, Next.js, Leadership, Figma, App Store, REST APIs, Team Leadership, Mobile Development, Git, Third-party APIs, REST, Front-end

Front-end Technical Lead

2021 - 2021
Mindful Chef
  • Built a collaborative engineering culture by empowering autonomous teams and advocating for bottom-up approaches.
  • Grew the front-end engineering team from 6 to 17 developers within six months.
  • Enabled the transformation from disciple-based teams into cross-functional squads.
Technologies: Agile Software Development, TypeScript, JavaScript, React, React Native, Redux, Scrum, Kanban, Engineering Management, Technical Leadership, HTML, CSS, Styled-components, Heroku, Next.js, Leadership, Architecture, Figma, App Store, REST APIs, HTML5, Team Leadership, Mobile Development, Git, Third-party APIs, REST, Front-end

Technical Lead

2020 - 2021
Gamesys Group
  • Empowered the transformation of moving to TypeScript and React Hooks.
  • Played an integral part in adopting a design system for all front-end web concerns across the company.
  • Provided a framework and process to empower developers to suggest technical improvements and tech health items.
Technologies: React, Flux, Node.js, Material UI, TypeScript, JavaScript, Koa, Technical Leadership, HTML, CSS, Sass, Leadership, Architecture, REST APIs, HTML5, Git, REST, GraphQL, Front-end

Principal Developer and Team Lead

2018 - 2019
Gamesys Group
  • Co-organized internal Innovation Days to experiment with new ideas and approaches for the front-end platform.
  • Streamlined repeatable and reliable hiring and onboarding processes, coordinating with internal recruiters and involving and upskilling developers.
  • Advocated and introduced microfrontends across multiple teams as a means to de-couple development, technology choices, and releases.
Technologies: Agile Software Development, Kanban, Engineering Management, Technical Leadership, JavaScript, Flux, Node.js, HTML, CSS, Sass, Architecture, Leadership, REST APIs, HTML5, Team Leadership, Git, REST, Front-end

Senior Front-end Developer

2017 - 2018
Gamesys Group
  • Drove the technical delivery of two greenfield projects with two different offshore teams.
  • Led the refactoring of the legacy build system to a modern alternative.
  • Introduced technical talks, bringing multiple teams together to share ideas and new patterns.
Technologies: JavaScript, Flux, React, Node.js, Webpack, HTML, CSS, Sass, Redux, REST APIs, HTML5, Git, REST, Front-end


2016 - 2017
  • Built out the deltaDNA analytics React Native module as an open-source.
  • Set up a continuous integration environment with work-in-progress automatically published internally to stakeholders and shareholders.
  • Sped up the process from wireframe to implementation and improved the collaboration between designers and developers by introducing Sketch and Zeplin workflows.
Technologies: React Native, JavaScript, Flow, Sketch, Zeplin, Node.js, Express.js, Redux, App Store, Mobile Development, Git, Third-party APIs, Front-end

Software Engineer

2015 - 2016
Binary Thumb
  • Built out continuous integration with CircleCI and created easy-to-use build and deployment processes to integrate with Amazon EC2.
  • Migrated the back-end CoffeeScript codebase to ECMAScript 2015+.
  • Discovered and experimented with effective ways of communication between on-site and remote employees.
Technologies: React, Node.js, JavaScript, UI Design, Amazon Web Services (AWS), Amazon DynamoDB, CoffeeScript, Hapi.js, Full-stack, APIs, App Store, REST APIs, HTML, HTML5, Git, REST, Front-end

User Experience Developer

2014 - 2015
Geniux Consulting GmbH
  • Developed small-scale products for several clients.
  • Focused on applications that run on mobile devices or have a touch component.
  • Oversaw DevOps tasks, such as continuous integration with Jenkins and creating easy-to-use build and deployment processes.
Technologies: Meteor, React, JavaScript, Node.js, CSS, HTML, React Native, Jira, GitLab, Jenkins, Full-stack, HTML5, Unity3D, C++, C#, Mobile Development, Git, Front-end

Software Engineer

2012 - 2014
CostXpert AG
  • Handled and provided most of the front and back end as the lead software architect.
  • Empowered other team members to contribute toward the open-source software we were using by creating processes and best practices for contributing to GitHub.
  • Defined and implemented a build pipeline based on Grunt, which processes, optimizes, and delivers client-side assets such as JavaScript files, images, and fonts.
  • Introduced and shaped Learning Fridays, where the morning was spent on internal talks showcasing learnings from working on the product, the latest developments in the JavaScript ecosystem, and industry best practices.
Technologies: CouchDB, Node.js, JavaScript, jQuery, CSS, Bootstrap, Express.js, HTML, Full-stack, APIs, REST APIs, HTML5, Git, REST, Front-end

Mobile Game Developer

2011 - 2012
retroteam UG
  • Created the initial iOS version using the Sparrow framework.
  • Implemented and adopted a cross-platform web version to simplify development across multiple platforms.
  • Set up analytics to capture core gameplay metrics.
Technologies: iOS, JavaScript, jQuery, Mobile Development, Front-end

Software Engineer

2011 - 2011
Acomba UG (Self-employed)
  • Created an initial prototype of their flagship product for iOS platforms using Objective-C and Cocoa Touch.
  • Provided documentation and best practices for turning the prototype into a published app.
  • Provided installers for different platforms to simplify the installation with the flagship macOS product.
Technologies: Objective-C, iOS, Dropbox API, Mobile Development, Front-end

Sparrow iOS Game Framework Beginner's Guide
Sparrow is a game framework focused on ease of use and current state-of-the-art technologies. The framework is intended for 2D games and multimedia applications and has built-in support for touch, animation, and managing objects on the screen.

The book, Sparrow iOS Game Framework Beginner's Guide, aims to teach a complete overview of how to develop a mobile game for iOS using Objective-C and Sparrow. Instead of teaching concepts separately, this book takes a methodical approach, taking readers through the development of an entire game using Sparrow's powerful framework.

Irrlicht 1.7 Realtime 3D Engine Beginner's Guide

The Irrlicht Engine is a cross-platform, high-performance real-time 3D engine written in C++. It features a powerful high-level API for creating complete 3D and 2D applications such as games or scientific visualizations.

The book, Irrlicht 1.7 Realtime 3D Engine Beginner's Guide, teaches how to master all that is required to create 2D and 3D applications using Irrlicht, from installation to deployment. It is a step-by-step guide to Irrlicht that starts at an easy level for beginners. It then gradually works to more advanced topics through clear code examples and demos illustrating theoretical concepts.

Starting with installation, the book guides readers through creating a basic template application, followed by meshes, overlays, and UI. Readers will then scan through data types, nodes, scenes, cameras, lights, and particle systems. Finally, readers will learn about some advanced concepts, such as handling data, files, and shaders, followed by the last stage: deployment.

React Amsterdam: React for Game Development
This is a talk I gave at the React Amsterdam conference in April 2016. React Amsterdam is an international conference for React developers. Please note that the slides are a bit delayed in the video linked to this project.


React, Node.js, jQuery, REST APIs, jQuery UI, Dropbox API


GitHub, Webpack, WebStorm, Figma, Git, Flow, Sketch, Zeplin, Jira, GitLab, Jenkins


React Native, Next.js, Bootstrap, Express.js, Ruby on Rails (RoR), Redux, Flux, Material UI, Koa, Hapi.js, Unity3D, NestJS


JavaScript, CoffeeScript, CSS, TypeScript, HTML, HTML5, Swift, Objective-C, Sass, Ruby, C++, Kotlin, C#, GraphQL


Mobile Development, Agile Software Development, REST, Scrum, Kanban, UI Design


CouchDB, Amazon DynamoDB


iOS, Meteor, Android, Amazon Web Services (AWS), Heroku, Visual Studio Code (VS Code), Mobile


Technical Leadership, Team Leadership, Front-end, Engineering Management, Full-stack, App Store, Third-party APIs, Styled-components, Budget Management, Metabase, CTO, Leadership, Architecture, APIs

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