Jeroen de Lau, Developer in Oegstgeest, Netherlands
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Jeroen de Lau

Verified Expert  in Engineering

Full-stack Developer

Oegstgeest, Netherlands
Toptal Member Since
August 7, 2020

Jeroen has eight years of experience working remotely. He's spent over a decade managing and developing IT projects, working as a developer, project manager, and product manager in various fields. He draws from each of those experiences to provide solutions for his clients. Most recently, Jeroen has focused on Shopify-related projects, including subscriptions, rates, shipment and fulfillment, and order management.


React, JavaScript, PHP, Unit Testing, MySQL, Functional Specifications...
Helium Pte Ltd
AWS DevOps, Amazon Web Services (AWS), Site Reliability Engineering (SRE)...
Dave Smith
PHP, Unit Testing, APIs, Cryptocurrency, Scraping, Node.js, WebSockets...




Preferred Environment

GitHub, Slack, JetBrains, REST

The most amazing...

...experience I've had was working with a group of young entrepreneurs at PocketChange, helping them grow and build something that matters.

Work Experience

Freelance Developer

2017 - PRESENT
  • Successfully executed 60+ contracts for over 30 clients.
  • Developed 10+ Chrome extensions for a variety of industries, from green nonprofits to Amazon sales tools.
  • Created five full-stack platforms, web clients, mobile clients, web back-ends, and AWS deployments.
  • Built out two teams, from being the first engineer to hiring and coaching four team members.
Technologies: React, JavaScript, PHP, Unit Testing, MySQL, Functional Specifications, Amazon Web Services (AWS), HTML, CSS, Node.js, REST, Jira, PHP 7, Serverless, Stripe API, Shopify API, JSON, Webhooks, Apache, LAMP, jQuery, Git, AWS Lambda, Serverless Framework, TypeScript, Amazon EC2, Amazon RDS, Amazon API Gateway

Senior Back-end Developer

2022 - 2023
Helium Pte Ltd
  • Implemented several key new features, including subscriptions, Shipping Rules, Rate Rules, and implementation of the new Fulfillment API, driving retention and increase in installs.
  • Matured the team, activating all members, and implemented CI and observability. Managed three people in three different time zones.
  • Helped design the new architecture to make the platform more user-focused.
Technologies: AWS DevOps, Amazon Web Services (AWS), Site Reliability Engineering (SRE), Product Development, Logging, Metrics, Distributed Tracing, DevOps, Ruby on Rails (RoR), Laravel, Shopify, Shopify API, Subscriptions

Back-end Developer

2022 - 2022
Dave Smith
  • Wrote scripts that retrieved all trades and order book data for 10 different exchanges, including Binance, FTX, and Huobi.
  • Converted JSON to Binary, reducing data storage needs by more than 95%.
  • Provided near real-time data to the quant team for trading algorithms.
Technologies: PHP, Unit Testing, APIs, Cryptocurrency, Scraping, Node.js, WebSockets, Architecture, Amazon Web Services (AWS), Serverless, JSON, Webhooks, Apache, LAMP, Git, AWS Lambda, Serverless Framework, Amazon EC2, Amazon RDS, Amazon API Gateway

PHP Developer

2022 - 2022
BT&M Investments LLC dba Qtego Fundraising Services
  • Built a no-password SMS and email login system. The system has users but no user table, so it required remodeling the data structure while maintaining backward compatibility.
  • Migrated the system to AWS using a combination of EFS, RDS, and Elastic Beanstalk, which included making the code server agnostic.
  • Introduced Composer, bootstrapping, a simple DBAL, and reusable classes.
  • Introduced a CD pipeline to deploy code to different environments automatically.
  • Created a multi-event login, allowing users to be logged in at multiple sites simultaneously.
Technologies: PHP, JavaScript, HTML, CSS, Auth, Single Sign-on (SSO), Architecture, Amazon Web Services (AWS), JSON, Webhooks, Apache, LAMP, jQuery, Git, TypeScript, Amazon EC2, Amazon RDS

Senior Full-stack Developer

2021 - 2021
Arctica Partners Limited
  • Designed, built, and deployed an MVP within three weeks (60 hours) for a system using the open banking API and royal mail API to evaluate green loans.
  • Received positive feedback on the MVP from two banks, allowing the client to work toward new milestones.
  • Launched the system on AWS, keeping running costs below $20 for six months.
Technologies: Amazon Web Services (AWS), Full-stack, Laravel, React, APIs, Online Banking, JSON, Webhooks, Apache, LAMP, Git, Amazon EC2, Amazon RDS

PHP Developer

2020 - 2021
Star Editions Ltd
  • Built a system that handles 100,000 orders from 50 stores across three platforms.
  • Lowered AWS running costs by $4,500 by queueing and batching. The system is able to handle order spikes without raising running costs.
  • Reduced error rate to 1/100,000, requiring almost no human intervention. The system has been running for two years with minimal intervention.
  • Made it possible for non-technical staff to locate any issues within seconds, allowing them to move on customers' inquiries quicker.
Technologies: PHP, MySQL, PHPUnit, Unit Testing, Amazon Web Services (AWS), Shopify, eBay, Amazon, Architecture, Laravel, Message Queues, React, Stripe API, Shopify API, DHL API, Stripe, JSON, Webhooks, Apache, LAMP, Git, Amazon EC2, Amazon RDS

Senior Product Manager

2014 - 2015
  • Led a team to continuously deliver revenue through content and feature updates.
  • Developed new IP by adapting an existing global hit to the Chinese market.
  • Delivered $400,000 in revenue for games through content and engagement campaigns.
Technologies: SQL, Vertica, Product Management, Analytics, Feature Roadmaps, Feature Planning, Data Analysis, HTML, Jira, Git

Director of Operations

2012 - 2014
  • Raised units and monthly revenue by 400%, over a six-month period.
  • Spearheaded Analytics, determining and exploiting key metrics that drive decision making.
  • Helped make in-house developed games a Git contributor to revenue and profit for the company.
  • Helped develop three profitable games and supported several others.
Technologies: Analytics, SQL, Tableau, Feature Analysis, Data Analysis, Jira, Apache, Git

Lead Developer

2011 - 2012
  • Created an inclusive work environment where individual talents could shine.
  • Restructured work processes and started delivering on deadlines.
  • Helped to create an atmosphere of renewed belief in a positive outcome of the project.
Technologies: JavaScript, PHP, HTML, CSS, Node.js, REST, PHP 7, JSON, Apache, Drupal, LAMP, jQuery, Git

Operational Director

2008 - 2011
Yourzine China
  • Product managed new EDM software worth a million euro.
  • Delivered products to international partners, meeting their high-quality expectations.
  • Built an eight-person offshore web team that can deliver products at an excellent value.
Technologies: JavaScript, PHP, Feature Planning, Functional Design, Lean Project Management, Data Analysis, PHP 7, Drupal, Drupal 7, LAMP, jQuery, Git

A project that started out as a browser extension, but it can now be called a giving platform. PocketChange empowers you to take action on the causes you care about, no matter where you are.

With an international team, we developed an app for every platform. As the lead developer, I worked with talented developers to bring this platform to the world.

Ziziup Web Extension

Ziziup provides a service where they ship products from mainstream sites to customers all over the world. The extension allows their customers to shop on the site of their choosing, but to check out using Ziziup.

At this point, the contents of the shopping cart will be transferred to the Ziziup website for the final checkout. The basic extension was completed inside a week, with additional time required to scrape the 80 shopping carts.

The extension is built to work in Chrome, Opera, and Firefox, but at the time of writing, its back end is still under construction.

Ka-Ching - Chrome Extension

The client was looking for an extension that would ping every time you sell something on Amazon.

Extension includes:
- Registration service
- Optional permissions
- MWS API integration
- Sound! :)

Simple but fun!

SellerRing - Chrome Extension

Multi-part project integrating many useful features into a single extension.

Phase 1: Quickly see if you can sell a product on Amazon.
Phase2: Integration with market research tools
Phase3: Bulk scraping and decision making tools

BaoBuddy - Shopify Site

The client was looking to develop a store that pulls information from and sells it to customers outside of China.

After investigation, we decided to go for Shopify. I built the site using the Shopify API to import each TaoBao item as a new Shopify product.

Work was completed in 80 hours over a two-week time span.

Label Printer - Browser Extension

A browser extension that takes information from Amazon Seller Central and allows users to send them straight to their label printer. The extension includes a subscription feature supported by a WordPress site.

The project was completed in about three weeks.
2000 - 2006

Master's Degree in Business Information Systems

University of Amsterdam - Amsterdam, NL


Shopify API, jQuery, React, Node.js, Auth, Stripe API, DHL API, Stripe


Jira, Zapier, Git, JetBrains, Slack, GitHub, Tableau, Apache, Logging


Laravel, PHPUnit, React Native, Serverless Framework, Ruby on Rails (RoR)


Unit Testing, REST, Agile, Agile Software Development, DevOps


PHP, JavaScript, HTML, PHP 7, CSS, TypeScript, SQL


Shopify, Amazon Web Services (AWS), Amazon, Drupal, Drupal 7, LAMP, Amazon EC2, AWS Lambda


JSON, MySQL, Vertica, Amazon DynamoDB

Industry Expertise

Project Management


Full-stack, Technical Product Management, Functional Specifications, APIs, Webhooks, Data Analysis, Architecture, Serverless, Amazon RDS, Amazon API Gateway, Analytics, Functional Design, Leadership Development, Product Management, Feature Roadmaps, Feature Planning, Feature Analysis, Lean Project Management, Browser Plugins, Single Sign-on (SSO), Cryptocurrency, Scraping, WebSockets, Online Banking, eBay, Message Queues, AWS DevOps, Site Reliability Engineering (SRE), Product Development, Metrics, Distributed Tracing, Subscriptions

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