Mark Topper Diderichsen, Developer in Holbæk, Denmark
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Mark Topper Diderichsen

Verified Expert  in Engineering

Software Developer

Holbæk, Denmark
Toptal Member Since
December 30, 2021

Mark has a big passion for performance, scalability, and security. He helped build the online supermarket's entire solution for shared economy between its users and shoppers called Vigo by REMA 1000. He has also been working with the implementation of new features and updates for the Copenhagen Airport APIs and servers for the mobile platforms, ensuring the stability and performance were within the acceptable threshold.



Preferred Environment

MacOS, PhpStorm, Slack, Laravel

The most amazing...

...thing I've developed is the back-end solution for a supermarket's online shop and delivery service, including validation of delivery purchases at the store.

Work Experience

Software Developer

2014 - PRESENT
Novasa Interactive ApS
  • Developed the back-end solution for a supermarket's online webshop and delivery services.
  • Created a message translation SaaS solution with scalability, handling many requests exceptionally well.
  • Maintained critical API services to ensure stability for Copenhagen Airport's mobile applications.
  • Built a vertical scalable server infrastructure with its own servers, allowing 99.99% availability for web services, cache, databases, and file storage.
  • Integrated multiple payment solutions securely into platforms, handling all the edge cases and possible bottlenecks.
  • Tracked and fixed bugs using automatic bug logging software such as Bugsnag and Sentry along with Jira.
Technologies: Laravel, PHP, Amazon Web Services (AWS), Servers, APIs, Firebase, Cordova, Swift, Web Security, MySQL, NoSQL, SQLite, Microsoft SQL Server, Slack, Slackbot, Slack API, PhpStorm, MacOS, Postman, Terminal, Unit Testing, PHPUnit, REST, JSON, XML, React, Vue, Performance, PHP Performance, SQL Performance, Jira, Git, GitHub, GitHub API, CI/CD Pipelines, Bitbucket, GitLab, Trello, Automation, Stripe, C#, Ubuntu Server

REMA 1000 med Vigo | Online Shop
A supermarket's take on an online shop, allowing their customers to purchase products online and have them delivered. Anyone can sign up to become a delivery person to start earning money.

Built their back-end infrastructure, service APIs, and customer support portal. The service APIs were heavily used by the webshop, mobile applications, and partners, requiring code to be stable and fast. The project succeeded and became a popular online shopping choice for many in Denmark.

Their mobile applications have been in the top 10 on App Store and Google Play in their related category. For security, I implemented a flow that allowed us to validate the purchase a delivery person did down in the store to ensure the user was not committing fraud. Then we could automate the process of orders to ensure human resources weren't overflowing with the workload.

Copenhagen Airport's mobile application was created and managed by my coworkers at Novasa. Meanwhile, I was in charge of the servers, API services, and administration panel.

The system runs various automatic tasks to keep the APIs updated with the latest data from Copenhagen Airport, even some time-critical details such as flight times and security waiting time.

The mobile application is in the top 50 of their category in Denmark on App Store and Google Play. The application is widely used, so the API services are built to perform.

Debt Collecting Automatization Platform
A Laravel-based application where clients can easily or automatically send unpaid overdue invoices to debt collection.

Invoices were automatically fetched in from various accounting and invoicing platforms, allowing clients to partner with this company no matter their invoicing method. Since all the invoicing details came automatically to the systems, it was straightforward and intuitive for clients to send in debt collections.

This project made it possible to automate much of the manual processing in this field of work and thereby allow to easier scale the number of active clients.

Coaching Platform

As a freelancer, I was contracted for a custom software development job to build the back end and server infrastructure for a coaching platform.

We made it possible for coaches to automate much of the client's time-consuming work with this project. The system needed to be fully translatable, fast, and scalable.

The system had to process an enormous amount of data within a short time. This was achieved with various cloud solutions to ensure that we could quickly scale up and down on workers for data processing.

Puzzible Social Messaging Application
Like Snapchat, Puzzible is a free messaging and social networking application for smartphones, allowing users to send messages and photos.

In addition to the features that Snapchat provided, Puzzible was created to allow users to generate a jigsaw puzzle from the photo that was taken. This was a unique feature that turned messaging into gamification.

I built the entire server infrastructure and API services. It was essential to the client that the system could scale and have high availability. Therefore I set up an entire scalable infrastructure with multiple load balancers, failovers, storage, database, and web servers to ensure availability.

Even if we had to shut down any of these services during maintenance, the system would still be running smoothly.

Open-source Admin Panel Solution
Laravel Voyager is an open-source solution, allowing developers to quickly set up an admin user interface for their web application using the Laravel framework.

The system allows non-developers to modify and configure their content, while developers can focus on the core integration. It includes BREAD (CRUD) operations, media manager, and menu builder.

I contacted the author, who didn't have the time to maintain the system, and then I became the maintainer of this open-source repository. I managed to maintain, support, and improve the system over many years until I quit my position as a maintainer after I stopped using the system myself.

While I was maintaining the solution, I managed to implement automatic tasks such as assets compiling, code style fixing, unit and feature tests, code coverage, and more automatic tasks to ensure the system continued to improve.

Besides that, I added multiple features to the system like translations, multilingual support, and plugins. The plugin support was by far the most complex but also the most loved and used feature, allowing non-dev users to easily browse and install (one-click) a plugin. It used Composer behind the scenes.

Real-time Poker Engine

I developed a custom poker SaaS platform as a single-page application (SPA) with a separated back-end solution.

The front-end platform is built using React as a SPA solution, Web Sockets for live game updates, and oAuth for authentication. The back-end solution is built using the Laravel framework for API and game data interactions. I also implemented both Stripe Connect and PayPal for payment gateways.

For customization, I added support for the businesses to customize the design of their poker site. To lower the dreadlocks for the database, I separated every game table into its own database, like the tenancy design.

Sadly the project is not yet publicly available, and it's been sold to a closed group of businesses. I am therefore unable to share the link or name at this point.

Certified PHP Developer

W3 School


Certified Laravel Developer

Laravel LLC


Vue, GitHub API, jQuery, Slack API, React, Stripe, Node.js, Stripe Connect


PhpStorm, Slack, Terminal, Git, GitHub, Trello, Postman, Jira, Bitbucket, GitLab, Android Studio, Xcode, Bugsnag, Shell, NGINX, Composer, NPM, Figma


Laravel, PHPUnit, Tailwind CSS, Redux, Next.js, Nuxt.js, Bootstrap, PHP MVC, Realtime


PHP, XML, JavaScript, HTML, CSS, Swift, C#, TypeScript


Unit Testing, REST, Automation, Agile Software Development, Microservices, CRUD, Modular Design, Maintainability


MacOS, Firebase, Amazon Web Services (AWS), Ubuntu, Docker


MySQL, JSON, NoSQL, SQLite, Microsoft SQL Server, SQL Performance, Redis, Memcached, Database Replication


APIs, PHP Performance, Ubuntu Server, Servers, Cordova, Web Security, Slackbot, CI/CD Pipelines, OAuth, WebSockets, PayPal, Chrome Extensions, Performance, Microsoft Servers, Customer Support, Payment Gateways, Ajax, API Documentation, Laravel Nova, Serverless, Caching, User Authentication, Scaling, Load Balancers, Cloud, Cloud Storage, Failover Solutions, Open Source, Squarespace, SaaS

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