Denis Ulmer

Senior software engineerStuttgart area, Germany

I’ve spent more than a decade designing and building reliable systems for global enterprises.

Open to conversations about senior software engineering roles, in the Stuttgart area or remote.

Take the tour Straight to my CV

Scroll to travel through five small paper worlds, one for each thing I love doing.

Stop 1 of 5

Family

The picture shows: In a sunny garden, Denis sits in the grass with a guitar next to his wife. One daughter is on a small slide and the other lies on a blanket.

I’m married, with two daughters. Most of our free time is spent together: cooking, biking, swimming, and long afternoons in the garden. I usually bring the guitar; the audience is small but very honest.

Next stop: Coding

Stop 2 of 5

Coding

The picture shows: Denis sits at a desk with two monitors. One shows a grid of star photos, the other shows code. A small telescope stands on the windowsill.

Coding is my job and my hobby. After hours I’m building a private astrophotography gallery with its own plate solver, which works out exactly which patch of sky a photo shows. I also built this site; you’re standing in it.

The day job is in my CV.

Next stop: Reading

Stop 3 of 5

Reading

The picture shows: Denis sits in an armchair under a reading lamp with a book open on his knees, next to a shelf full of paperbacks.

Science fiction is my favourite way to switch off. These are the books I keep coming back to, and press on anyone who asks.

  • The Mote in God’s Eye Larry Niven and Jerry Pournelle First contact told slowly and carefully, and all the more unsettling for it.
  • Daemon Daniel Suarez A thriller whose scariest part is how plausible the code is.
  • The Three-Body Problem trilogy Cixin Liu Physics on a scale that changed how I look up at night.
  • Ready Player One Ernest Cline A love letter to the games and films I grew up with.
  • Hyperion Dan Simmons Six pilgrims, six stories, and one of the best-built worlds in the genre.

Next stop: Astronomy

Stop 4 of 5

Astronomy

The picture shows: Under a starry night sky, Denis stands beside a white refractor telescope on a heavy equatorial mount, with a camera fixed to its end.

I’ve been photographing the night sky since 2011. My setup is a 130 mm apochromatic refractor on an AZ-EQ6 mount with an ASI1600 camera, and my favourite targets are the Pleiades, the core of the Heart Nebula and M16, the Eagle Nebula. Clear, moonless nights are rare here, so when one comes along, sleep can wait.

  • The Pleiades star cluster, a knot of bright blue stars wrapped in wisps of blue dust.
    The Pleiades (M45) Placeholder image
  • Glowing red gas and dark dust around the small star cluster at the core of the Heart Nebula.
    Core of the Heart Nebula (IC 1805) Placeholder image
  • The Eagle Nebula, with dark columns of dust rising into glowing gas.
    The Eagle Nebula (M16) Placeholder image

Next stop: Gaming

Stop 5 of 5

Gaming

The picture shows: Denis, in his yellow hoodie, sits on a couch with a game controller. A PC glows on a desk beside him and a console sits under the TV.

I play on PC and consoles, mostly JRPGs, racing games and strategy. Final Fantasy is where I learned to love a long story, Command & Conquer is where I learned to love a good build order, and Gran Turismo keeps me humble about my braking points.

That’s the tour. On to my CV

CV

I’ve spent more than a decade designing and building reliable systems for global enterprises.

Open to conversations about senior software engineering roles, in the Stuttgart area or remote.

Download CV (PDF) hello@denisulmer.dev

Experience

  1. Senior Software Engineer

    Festool

    to present

    • Full-stack development of internal tools and processes for logistics, manufacturing and suppliers.
    • Built an IoT platform for firmware and telemetry across tens of thousands of devices.
    • Introduced zero-downtime deployments on Azure Kubernetes Service.
    • Brought automated integration tests to every codebase and infrastructure as code (Bicep, Terraform) to every environment.
  2. Software Engineer

    Strack IT Solutions

    to

    • Designed and delivered custom software for industrial clients, mainly Festool.
    • Turned complex requirements from many stakeholders into maintainable products.
    • Introduced React to the company to raise quality and speed up development.
  3. Systems Engineer

    T-Systems

    to

    • Engineered the SAP private-cloud infrastructure behind Dynamic Services for SAP, serving dozens of enterprise clients.
    • Built internal tools and automations that saved more than 2,000 work hours a year, recognised with an improvement award.
    • Last-level support, plus incident and change management to ITIL standards.
  4. SAP Technology Consultant

    T-Systems

    to

    • Planned and ran SAP system upgrades for multiple clients within SLA.
    • SAP administration, including transport management and performance tuning.

Education

  1. Apprenticeship, IT specialist for system integration (Fachinformatiker Systemintegration)

    Deutsche Telekom

    to

    • Final exam score of 99/100; awarded “Young IT Talent” and “TOP Nachwuchskraft”.
    • Ran high-availability customer systems (SAP R/3, Red Hat Enterprise Linux, Oracle RAC) and automated their operation with Bash.

Skills

.NET / C#
  • C#
  • ASP.NET Core
  • Entity Framework
  • Blazor
  • REST
  • GraphQL
  • gRPC
Azure
  • Kubernetes Service
  • IoT Hub
  • Event Hubs
  • Functions
  • Service Bus
  • Bicep
  • Terraform
TypeScript / React
  • TypeScript
  • React
  • Tailwind CSS
  • shadcn/ui
  • HTML
  • CSS
Data and delivery
  • SQL Server
  • Cosmos DB
  • Azure DevOps
  • GitLab CI/CD
  • Agentic coding
  • Linux
  • Windows
Architecture
  • Domain-driven design
  • Modular monoliths
  • Microservices
  • Sagas and state machines
  • Security-aware design
  • Agile and Scrum

Languages

German
Native
English
Professional working proficiency

Say hello

Open to conversations about senior software engineering roles, in the Stuttgart area or remote.

hello@denisulmer.dev