
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.
Portfolio
Experience
- PHP - 15 years
- Full-stack - 15 years
- Functional Specifications - 12 years
- Unit Testing - 8 years
- Laravel - 6 years
- React - 5 years
- Amazon Web Services (AWS) - 4 years
Preferred Environment
GitHub, Slack, JetBrains IDE, 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
Self-employed
- 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.
Senior Full-stack Developer
SodaStream
- Parachuted into SodaStream by Pepsi. In a tense political situation, I managed to make myself an essential part of the team within days.
- Upgraded a 6-year-old application without testing, and continued deployment and 4 major versions behind in 2 weeks—including learning the platform, writing unit tests, documentation, and communication.
- Created the primary service that handles all SodaStream subscriptions. The system was successfully delivered and generated 7-digit revenue within 3 years.
- Introduced best practices to the rest of the team, performed unit testing, and handled GitHub actions and continuous integration.
PHP Developer
BT&M Investments LLC dba Qtego Fundraising Services
- Moved the platform to an auto-scaling infrastructure on AWS, saving the company thousands of dollars per week.
- Rewrote the server-side codebase using Laravel, while running up to 50 auction events a day, with no downtime.
- Rewrote the front end using React and introduced responsive design.
- Introduced unit testing, linters, static code analysis, and GitHub actions into the process. Improved the delivery speed of code to the platform by weeks.
Senior Back-end Developer
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.
Back-end Developer
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.
PHP Developer
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.
- Testimonial: "Jeroen is the best advertising Toptal can have."
Senior Full-stack Developer
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.
PHP Developer
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.
Senior Product Manager
Zynga
- 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.
Director of Operations
6waves
- 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.
Lead Developer
Creator.me
- 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.
Operational Director
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.
Experience
Subscription Service
http://sodastream.comBesides the deliverables, coworkers were particularly impressed by the rigor—good documentation of all features, a solid pipeline, fast deployments, high feature throughput, excellent visibility into what the system was doing, and a strong ability to monitor and troubleshoot.
Auction Site 2.0
http://qtego.comQtego serves thousands of companies that organize charity auctions. The original product was SMS auction support, but has since migrated to the web. With most events during the weekend and most bidding in the final minutes, their original server has reached its limit.
I was originally brought in to build a feature, but it soon became clear that my background and experience could greatly help. I stayed on for over a year and delivered the following:
• Unit testing
• Code quality tooling
• A completely new back end
• A responsive React front end
• Team motivation
In the end, Qtego can grow, and more impressively, we made the switch without affecting a single event.
PocketChange.social
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
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
Extension includes:
- Registration service
- Optional permissions
- MWS API integration
- Sound! :)
Simple but fun!
SellerRing - Chrome 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
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
The project was completed in about three weeks.
Education
Master's Degree in Business Information Systems
University of Amsterdam - Amsterdam, NL
Skills
Libraries/APIs
Shopify API, jQuery, React, Node.js, Auth, Stripe API, DHL API, Stripe
Tools
Jira, Zapier, Git, Slack, GitHub, Tableau, Apache, Logging, Lando
Languages
PHP, JavaScript, HTML, PHP 7, CSS, TypeScript, SQL, PHP 8, GraphQL
Frameworks
Laravel, PHPUnit, React Native, Serverless Framework, Ruby on Rails (RoR)
Paradigms
Unit Testing, REST, Agile, Agile Software Development, DevOps
Platforms
Shopify, Amazon Web Services (AWS), Amazon, Drupal, Drupal 7, LAMP, Amazon EC2, AWS Lambda, Azure, DigitalOcean
Storage
JSON, MySQL, Vertica, Amazon DynamoDB
Industry Expertise
Project Management
Other
Full-stack, Technical Product Management, Functional Specifications, APIs, Webhooks, API Integration, Data Analysis, Architecture, Serverless, Amazon RDS, Amazon API Gateway, JetBrains IDE, 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, GitHub Actions, Porting, Shopify Polaris, Horizon
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