Jean Mertz

Curriculum Vitae

I am a senior software engineer focused on the combination of high-level abstract APIs and low-level performance-driven systems. I am an avid learner and an excellent communicator. I am a pragmatic ethical engineer with a knack for software architecture, an eye for user experience and a capacity to lead.

As someone who has hired many people in my career, I’ve seen many résumé that sum up experiences, without telling the story of a career. If you want a quick glance at my experiences, I’ve got such a résumé for you to download right here – but if you want to get to know me on a professional level, I encourage you to read on. If you are interested, don’t hesitate to say hello!

  1. About Me — My personal experiences and lessons learned.
  2. Employment History — Not just who, but what and why.
  3. Personal Projects — That which I build for education and fun.

About Me

I am a senior software engineer focused on the combination of high-level abstract APIs and low-level performance-driven systems.

As a backend engineer I have worked extensively with backend systems, while also maintaining clients to interact with those systems. I enjoy working with high-level languages to abstract away business rules behind easy-to-use APIs and am also getting more interested in lower-level concepts such as memory management, CPU registers, cache lines, network packets and file descriptors to develop for resource-constrained environments.

I get excited by any opportunity to optimize processes within an organization either by automating that which can be automated, by applying UX improvements to systems that are operated by other humans, or by streamlining processes such as communication flows, team compositions and removing unnecessary red tape.

I thrive in a flat organization that values high impact contributions by all employees. I have a breadth of knowledge with a work ethic that allows me to be self-regulated and trusted in doing the right thing. Conversely, I don’t do well in constrained single-purpose roles that allow for little experimentation and have a highly regulated work regime.

I am a skilled communicator with managerial experience and a feeling for user experience which allows me to bridge the gap between different units within an organization. I enjoy coaching my peers and get fuzzy feelings when I can make a small contribution to the growth of others.

I am an avid learner of a diverse set of fields, such as software engineering, communication, management, mathematics, physics and astronomy. I enjoy learning new programming languages and engineering paradigms, I am a big proponent of learning by active reading and by expanding that knowledge by continued experimentation.

I am a huge space nerd and regret never having spent the time to graduate in physics & astronomy to allow me to combine my technical skills with my biggest passion. Never say never, but so far I consider this to be my biggest professional failure.

And last, but certainly not least, I am a family man that cares for his peers, the environment and surroundings. I take pride in my focus on solidarity and openness to diversity. I respect all walks of life that respect others and enjoy being around and working with people that bring life-perspectives that differ from my own. I try to avoid monoculture environments, even though unfortunately that is still difficult to do in our industry.

Skills and Technologies

A list of soft skills, programming languages, and software that I am familiar with.

Go ahead and search the list for whatever term is of interest to you. I don’t think it matters too much, as I have enough experience in most software fields to be able to pick up new technologies relatively quickly.

In the past three years, I’ve primarily worked with the Rust programming language, working on low-level systems-software.

Programming Languages

C, Elixir, Golang, Groovy, HTML/CSS, JavaScript, LUA, PHP, Python, Ruby, Rust, SQL, Shell scripting, Swift, TypeScript.

Data Stores

BigQuery, BigTable, ElasticSearch, MongoDB, MySQL, Redis, Postgres.

Operations Tools

Ansible, Chef, Docker, Istio, Jenkins, Kubernetes, Nomad, Packer, Prometheus, Terraform, Vault.


Amazon Web Services, Git, GitHub, Google Cloud Platform, Kafka, Pub/Sub, Rails, Sidekiq, Travis, Unix, Windows, iOS, macOS.

Soft Skills

Adaptability, Collaboration, Communication, Conflict management, Creativity, Critical thinking, Decision-making, Desire to learn, Flexibility, Focus, Leadership, Listening, Mentoring, Motivating, Problem-Solving, Project management, Time management, Troubleshooting, Work ethic, Writing skills.

Past and Present Roles

My experiences over the past decade have shaped my understanding of businesses and the role that software plays in automating, simplifying, and enriching the world.

As a Technical Support Agent I know that software exists to serve the needs of the customer. What might be obvious to you is not always obvious to others, and your software should reflect the diverse world we live in, serving both able and impaired people from all walks of life.

As a Site Reliability Engineer I know that trust in your organization is the most valuable relationship you can have with your customers. Trust can be lost in a short timespan, but takes many more cycles to regain. The stability of the systems your business operates on is of critical importance, and is worth more than it seems. Prevention trumps cure, so observability must be a big part of your operation to ensure smooth sailing.

As a Software Engineer I’ve learned to build systems as complex as they need to be to fulfil their role within a product or organization, but no more complex than that. I’ve learned that every line of code is a liability that adds operational costs to an organization and must therefor be justified to exist. Documentation done right is a highly valuable asset to any organization, but done wrong can become an unwelcome time sink.

As a Software Architect I understand that software does not exist in a vacuum and must always serve a higher purpose in collaboration with other systems, both internal and external to the organization. The whole of these systems must be in-tune or risk slowing down the speed at which an organization can iterate. A ubiquitous language surrounding the domain models used throughout the organization is a highly valuable asset that warrants significant intellectual investments.

As a Technical Lead I realize that delivering a successful product is the result of a combination of short bursts of intense periods of activity spread out over a longer period of time. Sprints are needed to make sure you meet your short-term goals while never losing sight of the clarity and planning needed for a sustainable long-term marathon. Technical debt is part of every organization, and must be paid off at a constant pace, to not drag down the speed of iteration. It must never be allowed to become a reason for not shipping on time.

As an Engineering Coach I know that every engineer is a human being with needs, personality traits, misfortunes and personal goals. The software running the organization is only as good as the strength and happiness of your team. Engineers are smart, dedicated and always re-educating themselves, provide in that thirst for knowledge, and you have a formula to sustain your most valuable assets. Give your best engineers plenty of opportunities to learn from others outside your organization, while allocating their time wisely to help them teach those within your organization.

As a Chief Technology Officer I’ve experienced the importance of the collaboration between tech, product, marketing, and operations. All of these departments need to work in tandem for an organization to succeed. None serves the other, but all serve the mission and vision of the organization. A technical roadmap is of no value on its own, but must strike a balance between achieving technical excellence, and delivering on planned product features.

As a Human Being I know that I want to do good for this world, and want to leave it in a better state than I found it. I realize that software – similar to other tools – can be used for good and bad, and I choose to only use it for good. I am principled in that way, and I do not apologize for that. The mission statement of an organization matters a great deal, the way the organization lives up to that statement on a day-to-day basis matters even more.

Personality Traits

Some more serious than others, here’s a short-list of what I find interesting or questionable about myself

  • I can get watery eyes when I see a touching moment
  • I have a terrible memory, and need to write everything down
  • I enjoy being around cats, but also love dogs and other animals
  • I aspire to one day write an educational open-source game about space exploration
  • I am afraid of forgetting people’s names
  • I get fuzzy feelings when I watch rockets launch to space
  • I exercise too little, and continuously watch my calorie intake to stay healthy
  • I enjoy video games, but hardly ever play because ”I have more important things to do”
  • I have unfortunately grown to dislike social media and stay off of it as much as possible.
  • I have a strong feeling of OCD when it comes to the cleanliness of my office, desktop environment, etc.
  • I prefer the countryside over city life
  • I have a slightly addictive personality and avoid anything that I consider to be harmful and addictive
  • I am worried about what little privacy we have left in our civilization
  • I don’t drink coffee or tea, and almost exclusively drink tap water
  • I get easily distracted in open-office spaces and work best in isolation
  • I have long had a feeling of impostor syndrome, but that has faded over time
  • I struggle with being brief and to-the-point (it’s okay to laugh now)
  • I strongly dislike advertisements and instead pay for software, content and services whenever possible.
  • I have a light case of ”benign essential tremor”, it does not impact my life significantly, other than I will never beat you at a game of wire loop.
  • I like to read educational books (and writing down what I learn)

Employment History

I’ve mostly worked at startup and small-size companies. I’ve worked for one enterprise-level company in the past, but found out that the working environment in such a large company does not suit my style, and so I plan on working in smaller sized companies going forward.

Current Status: Open for New Opportunities as of August 2023

As of August 2023, my engagement with Grafbase is coming to a successful close, opening up availability for new client projects. I'm currently in the process of exploring new opportunities.

This page will be updated as soon as I embark on a new project with an exciting tech stack.

Earlier Work


In April 2023, I shifted from a role at Datadog to resume my freelancing and consulting career. As a contractor with the Grafbase team, I contributed to the development of edge-based GraphQL servers, primarily leveraging Rust and compiling the code to WebAssembly.

During my stint at Grafbase, I:

  • Built a GraphQL connector, allowing to unify existing GraphQL APIs at the edge with Grafbase,
  • improved the RFC process for the team to better plan for features,
  • lead an (ongoing) project to open-source parts of Grafbase's tech stack.


On February 2021 Datadog — the world's leading observability company — did a talent acquisition of one of my clients, Timber. As part of the acquisition, my role changed from a contractor at Timber, to a full-time employee at Datadog.

The work I do at Datadog has changed relatively little, compared to my contract work at Timber. Most of my time is spent working on the open-source project Vector, developed using the Rust programming language.

More specifically, I am the lead developer of the Vector Remap Language DSL used to remap observability data in Vector.

In this capacity I have lead an engineering team, written and reviewed numerous RFCs, written large chunks of the language implementation, and initiated the VRL design document. In short, I have contributed significantly to a programming language that is used by the majority of Vector users, which includes many S&P 500 organizations.

Given that the code of Vector and VRL is open-source, all of my work is publicly available in the online repository.


From January 2020 – January 2021, I worked as a contractor for Timber, a start-up company changing the way that other developers use logs.

In the first six months, I mostly worked on an internal log management tool, written in Golang and Typescript, using React and GraphQL.

Later, I switched roles to work on an open-source high-performance observability data pipeline product, named Vector, written in Rust.


From May 2020 – November 2020, I worked as a contractor for OneSignal, the market leading self-serve customer engagement solution for Push Notifications, Email, SMS & In-App.

At OneSignal, I worked as a senior Site Reliability Engineer working in both Golang and Rust.


From January 2015 – January 2020, I worked at Blendle, a scale-up-phase startup leading the charge in modernising the distribution of journalism in the internet age.

As a Software Engineer (January 2015 – February 2016) I joined a small team of engineers that started the company, working on rapid iterations of our product, building out the software and infrastructure stack required to support our exponential growth. In this role, I:

  • helped the adoption of software methodologies such as agile software development, test-driven development and pair programming,

  • led a greenfield ”Blendle Button” project written in Ruby and React,

  • led the transition to a cloud-native Kubernetes-based infrastructure stack,

  • focussed on optimizing our communication and automating that which could,

  • took on the role of scrum lead in several projects,

  • built an in-house CI/CD pipeline on top of Jenkins and Kubernetes,

  • collaborated on a high-performance Go-based even-driven email delivery system,

  • built and integrated the ”Blendle Premium” subscription service with payment service providers,

  • built a high-performance Go-based analytics pipeline on top of Kafka.

As the Chief Technical Officer (February 2016 – January 2019), I:

  • Was responsible for the engineering team and the software stack,
  • collaborated in our hiring efforts,
  • helped our engineers grow by coaching them and helping them in their personal development plans,
  • helped foster a culture of software engineering and architecture,
  • set out the technology roadmap in collaboration with the product roadmap,
  • kept in close contact with our partners,
  • worked closely with our product, marketing and operations divisions,
  • introduced the Spotify model of ”guilds” and led weekly check-in meetings,
  • collaborated with Blendle's privacy & security officer on relevant topics.

As a Lead Software Engineer (January 2019 – January 2020), I:

  • Conducted numerous in-depth multi-hour interviews with candidates to find the right person to replace me as the CTO of Blendle,
  • re-found my passion and refocused my efforts on being actively involved in software engineering and architecture,
  • stayed involved in non-technical duties such as the hiring process,
  • collaborated with the product teams on software architecture decisions,
  • built an automation system in Rust and WebAssembly for non-engineers.

I have grown significantly as both an engineer, software architect and a leader during my time at Blendle. Through passion and dedication I have expanded my knowledge not only on a technical level, but also on a communications and managerial level.

Throughout my journey from engineer to CTO and back to engineer, I have found a balanced combination of passion and dedication for the craft of software engineering combined with my natural talent and enjoyment of helping others grow and leading teams and projects. Merging both disciplines in a balanced manner.

Software Engineer Consultant, ASM Lithography (ASML)

From April 2014 – October 2014, I worked as a consultant from Kabisa ICT for the Dutch lithography company ASML. During my stint at ASML I worked with Ruby, Perl and Windows Batch scripts. I also worked on an enterprise scale Jenkins CI/CD setup and took on the role as a scrum master within our division.

Software Engineer, Kabisa ICT

From September 2012 – January 2015, I worked on multiple projects, both in-house and on-site at customers. My main language of choice was Ruby, combined with the Rails framework, but there were some other languages as well (including JavaScript) and there was a not insignificant focus on infrastructure as code using Unix, Chef, Puppet and later Ansible and Docker.

Freelance Software Engineer

From April 2009 – September 2012, in my early years after graduating I worked as a freelance software engineer, doing mostly contract jobs for local companies. I used languages such as PHP, Ruby, HTML/CSS and JavaScript to write custom CMS systems, mailing list systems, and maintained websites for customers.

Study: Multimedia & Software Engineering

I studied and graduated from the University of Applied Sciences ”Hogeschool Zuyd” in The Netherlands. The study (formally called ”Communication & Multimedia Design”) introduced me to a cross-section of disciplines that proved useful in my future career such as software engineering, graphics & user interface design, marketing and communications. I knew early on that my passion would lead me down the software engineering road, but all other skills taught to me here have helped me achieve what I have achieved so far.

Personal Projects

YouTube Code Sessions

Watch me work on open-source projects, while learning Rust and game development.

Rustic Games (work in progress)

An open-source game about space engineering and exploration.

Jilu (Rust)

Generate a change log based on the state of your Git repository.

Conventional (Rust)

A rust parser library for the Conventional Commit spec.

Automaat (Rust/WebAssembly)

Automate repeatable tasks for everyone within your organisation.

Hubbit (Ruby)

Hubbit is your friendly neighborhood bot.

go-streamprocessor (Golang)

Shared library for Go-based stream processors.

Kubecrt (Golang)

Convert Helm charts to Kubernetes resources.

Zapdriver (Golang)

Blazing fast, Zap-based Stackdriver logging.

That’s all folks 👋, and remember; don’t hesitate to say hello!