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New tech is disrupting your world now. React.

Launch innovative products

New technology brings new oportunities. We help you build fast, scalable and reliable protoypes with our dedicated Lean team to test the market fast minimizing risk. If you need capabilities or the pace of your organisation stops you, we build it with you in a safe environment.

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Learn cutting edge tech

New technology creates competitive advantage. Master the one that is disrupting and taking over the web, from mobile to desktop, from IoT to real-time apps. Our specialized training helps you adopt the new JavaScript and stay ahead by implementing the best practices and tools.

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LeanJS brings you Lean Startup and JavaScript excellence on demand

Learn with us

We provide high quality training on cutting edge technologies. We don't teach how to solve a problem with certain tools, we help you think and understand why and how to use them.

A day in our training

Live coding

You will be introduced to new concepts with live examples rather than static presentations. This way we can enhance interactions between participants and instructors, and therefore instructors can provide tailor-made examples to participants’ queries.

Pair Programming

We believe two people working together is more efficient than two people working individually. By working in pairs participants have to explain to their partners what they do rather than just doing it. Explaining is a great way to learn and to make sure concepts are clear.


Our experienced instructors will unblock and guide participants when they are coding. Instructors will guide participants and make them think about how to solve problems.


We are strong believers in learning by doing, and so we want participants to code as much as possible so they can make mistakes in a safe environment and learn from them.

September 24th, 25th, October 1st. 1 Fore St, EC2Y 5EJ, London. Twelve hours per day, 3 days. 1 instructor for 10 developers.


Why you should do this bootcamp

React is right now the most efficient way to build fast and performant complex web applications. React’s first choice is JavaScript standards rather than creating its own particular way as other frameworks may do, so developer on-boarding is easier. It is also one of the youngest technologies among their counterparts and so it is difficult to find experienced developers who know how to build apps using React the right way.

This is a great opportunity to learn React from an experienced developer and instructor. With this intense bootcamp, you will learn quickly how to build React apps avoiding the pitfalls of learning when you do your first production app and you are likely to make mistakes that could impact on your business.

What are others saying about our workshops?

See previous workshops

React Bootcamp Objectives

On completion of the bootcamp each student will:

  • Understand the core principles of React ecosystem: react, react-router, redux
  • Be able to develop and test complex and reliable React applications: enzyme, chai, mocha, sinon, jsdom
  • Understand the best practices for front-end JavaScript: node, npm, webpack, es6, functional JS and OO JS


Day 1 (). September 24th. 12 hours: react, react-router

  • Build your first component
    • <App/> : Which framework do you think is used here?
    • Everything is a component
  • Virtual DOM and JsX
    • JsX vs React.createElement
    • Developer tools
  • What is React made up of
    • Props and State
    • Components with and without state. Classes Vs Functions
    • What you sould not use: React.createClass(), mixins, etc
  • Thinking in React and performance tips
    • One way data binding
    • Composable and reusable components
    • Higher order components
  • Forms management in React
    • Controlled Components Vs Uncontrolled Components
  • Implement React in an app with dummy data
  • Component lifecycle
  • Data management
    • Presentational Components vs Container Components
    • Fetching data
  • React Router
    • Main components: Router, Route, IndexRoute, etc
    • hashHistory vs browserHistory
  • Testing with Enzyme, Jsdom, Mocha, Chai and Sinon
  • Apps vs Webs: react-bootstrap and material-ui
  • Improve the previous React app with React Router and real data

The first day costs £ 495 per attendee (discounts available for groups).

Do you need a scholarship? (up to 50%)

Day 2 (). September 25th. 12 hours: redux

  • What problem is Redux solving?
  • Redux Principles
    • Store, Reducers, Actions
    • Composition and other best practices
  • Architecting your React app with Redux
    • Unique source of truth: router, localStorage and Redux
    • react-redux: Provider and connect
    • Using together react-router and react-redux
  • Refactor the app of the previous day to use Redux
  • Improving Redux
    • Redux level 1: Action creators
    • Redux level 2: Promise middleware
  • Connecting Redux to the server
    • Fetching data from the server to Redux
    • Updating data from Redux to the server
  • Improve the app connecting Redux to the server

The second day costs £ 495 per attendee (discounts available for groups).

Do you need a scholarship? (up to 50%)

Day 3 (). October 1st. 12 hours: advanced react & redux

  • Going isomorphic with React
    • Nodejs + React + React Router.
    • Isomorphic Redux? When and How.
  • Implement an isomorphic React + Redux app using a boilerplate
  • Advanced unit testing
    • Design code that can be easily tested. Best practices and patterns to design your components
    • Dependency Injection in React
  • Write unit tests for the most complex scenarios of the previous app
  • Functional programming
    • Composing functions
    • Currying
  • Advanced Redux level 3: Thunks. Actions that dispatch actions
    • Use case: displaying loading indicators
    • Use case: displaying error messages
  • Implement loading indicators in the previous app using thunks
  • Advanced Redux level 4: Middleware API.
    • Normalizr
    • Declarative action creators
  • Implement the middlware api in the previous app

The third day costs £ 595 per attendee (discounts available for groups).

Do you need a scholarship? (up to 50%)

In order to participate in our intensive React Bootcamp you need to know HTML, CSS and at least one programming language (like Java, .NET, PHP, JavaScript, etc) and web development.

An interview will take place to attend the training. Attendees need to have a minimum skill level so we can maximise the learning.

We're aware that our industry is somehow exclusive and not diverse enough and so some groups are excluded. Therefore we are delighted to support the following groups with a 20% discount for each group in both the React training and also in the JavaScript training (displayed below). Maximum discount is 50%:

  • * 20% discount Students, unemployed people and charity workers.
  • * 20% discount Women.
  • * 20% discount Freelancers and independent developers who become mentors of our community.
  • * 10% discount If you do the 3 days of the bootcamp.

* Maximum discount is 50%

More info at react@leanjs.com

Contact now

Learn React on your own

Do you want to learn React but you cannot afford our bootcamp even with our scholarship? We have created a list of posts and videos to help you learn React on your own: learn-react.com

HTML5 & CSS3 Specialist Course

3rd June, 2016. London, UK. 12 hours. 10 developers max. One classroom (1 Fore St, London )


  • Getting started with git and Github
  • Mobile First, responsive designs, grids and other patterns
  • Introduction to CSS3 and HTML5 Koans
  • Introduction to Less CSS Koans
  • Creating our own CSS Zend Garden
  • Creating our small Bootstrap
  • Extending Bootstrap

£ 495 - SOLD OUT

React Developer

At LeanJS we are looking for a talented front-end developer who loves being on the cutting-edge JavaScript technologies, learning and mentoring other devs. Skills required:

  • Strong JavaScript development skills and knowledge of React and Redux (or strong desire to learn). React Native is a bonus.
  • Strong analytical and problem solving abilities with meticulous attention to detail.
  • Testing excellence, unit testing and E2E. Tools: Mocha, Chai, Sinon, Enzyme and Nightwatch.
  • Coaching to Junior Developers, reviewing code and pair programming.
  • Open source and community oriented mindset.
  • Experience working in agile environments, Scrum or Kanban. Knowledge of Lean Startup and entrepreneur mindset is a bonus.

Apply at react@leanjs.com

Apply now

We develop it with you

Launch new products minimizing risk. The Lean Startup methodology provides a scientific approach to get a desired product to customers' hands faster. We have been using it since 2010.

Work smarter

The Lean Startup approach is based on the premise that every innovative project is a grand experiment that attempts to answer this question: "Should this product be built?" and "Can we build a sustainable business around this set of products and services?" This experiment is more than just theoretical inquiry; it is a first product. If it is successful, it allows a manager to get started with his or her campaign: enlisting early adopters, adding employees to each further experiment or iteration, and eventually starting to build a product and a new business around it.

We help you build the MVP

An MVP can be from a simple landing page to a small app that involves real-time or IoT to validate a hypothesis. If you need capabilities or the pace of your organization stops you, we can help you deliver a high quality MVP in few weeks to test an idea and iterate over it. Deliver the right functionality with the right quality. We help you shape the right team.