Hi, I am Martijn. đź‘‹ I am a passionate

Freelance React Developer

I am open to a challenging new job as of 1 August. Contact
Martijn Hols (2023)

About me

I am an experienced developer, specialised in React, with a lot of full stack experience. During my work experience (regularly as React Tech Lead) I was responsible for (the architecture of) several large projects. As a React Developer (or React Tech Lead) I can do a lot for a team.

I prefer to work “under the hood” in the React landscape. Things like the project setup/architecture, TypeScript, performance, accessibility, service workers, backend integrations, CI/CD, complex interactions of components, maintainability, stability, and improving the team’s velocity fascinate me. I focus on both the User Experience (UX) and the Developer Experience (DX) so that users and developers can work optimally within the project.

I enjoy working with others and find it important to share knowledge within a team. I also like to think along with stories, and with more than 6 years of React-specific experience and more than 15 years of web development experience, I have a lot of knowledge about this landscape. I have designed and built several SPAs and PWAs from scratch (functional and technical), including esd.next, WoWAnalyzer, the PME Legend webshop and Jetje. More on that in my resume and further below.

You can download my resume in Dutch on the Dutch version of this site.

Projects

Results that I am proud of.

Amels Yachting (2022)

Amels

Amels Yachting is the most animation and video-heavy project that I have worked on until now. It shows, as especially the portfolio pages are among the most visually appealing pages on the web, providing the user with a great experience to discover the Amels superyachts.

Achieving this did not come without some major challenges. Examples of this are the image sequence, highlights and interior/exterior design modals of the portfolio pages. As you can see, these work excellently on almost all devices and browsers and as well as possible with visitors with less bandwidth at their disposal.

React
,
TypeScript
,
Next.js
,
Storyblok
,
Azure DevOps
,
Cypress
,
Emotion.js
,
Algolia Search
,
Cloudinary
,
GraphQL
,
Scrum
,
CSS animaties
,
static rendering/prerendering

martijnhols.nl (2022)

You are here

My website to become better findable as a Freelance React Developer. Of course it's made in React, with Next.js as framework and Prismic as CMS. The source code is available on GitHub.

Open Source
,
React
,
Next.js
,
Prismic
,
TypeScript
,
React Query
,
SSG

Jetje (2021 - 2022)

Jetje

Jetje is a start-up that I started with a partner. We are developing an app to support customer-centered services, with integrated chat and (video)calls among other things. Our first implementation is coaching, but we are thinking much bigger. The app is primarily a React web app with Node.js backend, in TypeScript with GraphQL for complete type safety from start to finish. It features a comprehensive test suite, including Cypress for end-to-end testing. There is also a React Native app for (chat) notifications. Check out the Jetje and Geef 'm van websites for more information about the platform (Dutch only), or contact me.

React
,
React Native
,
TypeScript
,
Next.js
,
GraphQL
,
Apollo Client
,
Node.js
,
Apollo Server
,
service worker
,
GitHub Actions
,
Docker
,
GraphQL code generation
,
Jitsi
,
Yarn workspaces
,
Cypress (E2E testing)
,
Prismic
,
SSR
,
Static Site Generation
,
LighthouseCI

New Faith Network (2022)

New Faith Network

For the video platforms WithLove and New Faith Network, I rebuilt the landing and onboarding pages in two short months with React, Next.js, Prismic, TypeScript and Cypress. With the changes, the development team has an increased velocity building software that's more stable and more future-proof, with improved tracking from new events and the best possible performance.

React
,
TypeScript
,
Next.js
,
Gatsby
,
GraphQL
,
Prismic
,
Cypress
,
Netlify
,
GitHub Actions
,
SSG
,
Yarn workspaces

WoWAnalyzer (2017 - 2021)

WoWAnalyzer

I started WoWAnalyzer in 2017 from the desire to automate analysis of the game World of Warcraft. WoWAnalyzer automatically provides players with insights and suggestions for improvement based on their playstyle. It is primarily a React app. Within the app I developed a framework so that other developers could easily extend the analysis. It has become an immensely popular project with over 550,000 unique visitors in one month (January 2021) and over 200 contributing developers, all under my leadership. The project is completely Open Source. WoWAnalyzer has been used as an example of giving feedback in the book The Engagement Game, and a lecture and article. Since the end of 2021, WoWAnalyzer has been acquired by RPGLogs.

Open Source
,
React
,
TypeScript
,
Redux
,
Node.js
,
Express
,
Docker
,
GitHub Actions
,
Yarn workspaces

Swiss Sense (2019 - 2021)

Swiss Sense

Swiss Sense is a large box springs and mattresses bed store. For Swiss Sense I made, among other things, the boxspring configurator, made a plan to incrementally migrate the app to React, created microservices and major maintenance on the microservices framework, accelerated the CI and got Magento 2 working in Docker.

React
,
TypeScript
,
Node.js
,
GraphQL
,
Apollo Client
,
Apollo Server
,
Apollo Federation
,
microservices
,
Docker
,
GitHub Actions
,
GitLab CI
,
Lerna
,
Yarn workspaces
,
Cypress
,
Scrum
,
JIRA
,
SEO (e-commerce)
,
static rendering/prerendering

PlatteTV (2020 - 2021)

PlatteTV

PlatteTV is one of the largest TV stores in the Netherlands. As Front End Lead Developer I played an important role in the construction of their brand new webshop. I set up the project from scratch and developed the project approach (including SCRUM methodology) together with the project lead and led the team. This ambitious project was made in React with TypeScript, GraphQL, Apollo Server, and many microservices including Magento 2 and Pimcore as backend.

React
,
TypeScript
,
Node.js
,
GraphQL
,
Apollo Client
,
Apollo Server
,
Apollo Federation
,
microservices
,
Docker
,
GitHub Actions
,
GitLab CI
,
Service Worker/PWA
,
Lerna
,
Yarn workspaces
,
Cypress
,
Magento 2
,
Scrum
,
JIRA
,
SEO (e-commerce)
,
static rendering/prerendering

PME Legend (2019 - 2020)

PME Legend

The official webshop for the (in the Benelux) very popular clothing brand PME Legend, and associated brands Vanguard, Cast Iron and Just Brands. These were the first React webshops that we developed at Emico. Together with a small team, we built these webshops from scratch. Within a short time I had proven myself within this project and I became responsible for a large part of the architecture. The client was very satisfied with the new webshop, which resulted in a significant increase in conversion and was able to handle thousands of simultaneous visitors (including from commercials around the European Championship 2020).

React
,
TypeScript
,
Node.js
,
GraphQL
,
Apollo Client
,
Apollo Server
,
Apollo Federation
,
microservices
,
Redux
,
Docker
,
GitHub Actions
,
GitLab CI
,
Service Worker/PWA
,
Lerna
,
Yarn workspaces
,
Cypress
,
Scrum
,
JIRA
,
SEO (e-commerce)
,
static rendering/prerendering

esd.next (2016 - 2019)

ExternalStaffingDesk

esd.next is a unique system to streamline the entire hiring process of personnel. The system is complete and contains functionalities from vacancies and CV parsing to invoicing and automatic bookings. I designed this system from scratch with a partner and built it in PHP with a React SPA. An important principle was to give the user full control over the system. We have done this, among other things, by making almost all fields optional and keeping track of compliance with monitoring rules. The system is often compared to gigantic systems such as NĂ©tive and Salesforce and experienced as a breath of fresh air. Visit the esd.next sales page for more information (Dutch only).

React.js
,
Redux
,
PHP
,
Docker
,
MariaDB
,
TravisCI

modelovereenkomstmaken.nl (2016)

modelovereenkomstmaken.nl

With a few simple steps you can make a legal contract completely free of charge within 15 minutes, based on an approved model agreement from the Dutch Tax Authorities. This tool, which I built within 4 weeks, consists of a React application with minimal PHP backend. Users can easily and quickly select the right contract, fill it out and save it using an interactive contract form.

React.js
,
Redux
,
PHP
,
Docker
,
MariaDB
,
TravisCI

When at Work (2015)

When at Work

When at Work is an iOS app that automatically keeps track of when you are on location, based on geofencing, in order to largely automate your time registration, with options to adjust it manually, automatically take into account things like lunchtime and separate projects. I built this app completely independently as part of my graduation at HAN.

Swift
,
iOS
,
XCode
,
App Store

Elite Avengers (2004 - 2011)

Elite Avengers

Back in 2004 Elite Avengers was the first large project I started and worked on. It was a text-based online mafia game that has seen thousands of players. It existed mostly in PHP4 with a sprinkle of JS. Adding JS was a significant challenge as this was before the release of libraries like jQuery making even basic things like simple AJAX calls hard, not to mention the trouble dealing with Internet Explorer. Considering this was my first real development experience and I had no one to ask for help, I was in way over my head. This project has had a massive impact in training me to solve any problems I ran into on my own, work on maintainability, refine my English, make business decisions and deal with players/customers and volunteers.

PHP
,
MySQL
,
Linux
,
JS
,
Photoshop