Erik Olsen
XCA Consult ApS
XCA Consult ApS is a one-man consulting agency run by Erik Olsen — an M.Sc. mathematician turned software architect with 20+ years of experience building IT in the financial sector. This work spans everything from large insurance policy platforms to high-performing mobile payment systems.
Most of my work has been at the heart of IT modernisation: splitting domains into smaller, well-defined business services using domain-driven design and microservices. I contribute across the full journey — from decomposing the problem space and system design, to coding, testing, and deploying the solution.
I am independent, always work with quality in mind, and strive to solve real problems for customers.
Professional Experience
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External Consultant (Developer and Architect) — BankData 2026–present
My role was to contribute to the Online In Cloud program both as a domain architect and developer in the "login og signering" team in the security area. The overall objective was to help modernizing the area from both a technology and development point of view.
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Software Developer — Payment Engine, Vipps MobilePay 2023–2026
My task was to do development in the payment execution space, that includes migrating to the Vipps Azure platform, implementing paying with the eWallet product Box and enabling inter european money transfers to and from Vipps MobilePay users.
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Tech Consultant (Architect) — Lunar 2022
Architect in the Lending and Credit colony at Lunar, investigating new initiatives and sparring with developers on development, cloud, automated testing, service design and domain design.
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Developer and Architect — OK a.m.b.a 2021–2022
Designing and creating APIs on a Kubernetes platform using Domain Driven Design and token based security based on Azure AD.
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Lead Developer and Architect, API Tribe — Danske Bank 2020–2021
Designing and creating APIs on an Openshift Cloud using Domain Driven Design and token based security.
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External Consultant (Architect and Tech Lead) — BankData 2019–2020
Onboarding and teaching teams developing APIs on the new Openshift platform. Covered practical architecture and the principles of cloud development as an external consultant.
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Freelance Consultant — Mjølner 2018–2019
Developer on client projects and pre-sales as part of an architect team. Pre-sales work included domain discovery using DDD methodologies (Event Storming and context mapping) and writing IT project propositions.
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Senior Developer — MobilePay 2015–2018
Helped create the new application architecture and implemented it in the security team.
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Senior Developer — eBay 2012–2015
Feature development and maintenance of the bilbasen.dk site.
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Developer — Edlund A/S 2006–2012
Development on Skade.Net, an insurance platform, with a focus on integrations and policy calculations.
Education & Certifications
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M.Sc. Mathematics — Aarhus University 1998–2004
Master's degree in Mathematics specializing in Geometry and Topology.
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TOGAF I + II Certification — The Open Group 2017
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Certified Scrum Master — Ative 2009
Development
Languages
Frameworks
Tools
Technology
Cloud & Platforms
Messaging
Data
Observability & CI/CD
Architecture
Micro Services
APIs
Security
Other Skills
Certifications
Methods
Languages
Software Development
I specialize in designing and creating software and am a driver of all aspects of software development — from refining and designing to development and maintenance. I have a keen eye for balancing time, scope and technical ambition.
Architecture and development is best done in close collaboration and driven by business needs. With me on the team you get a senior developer and architect who is a team player and an excellent communicator.
Architecture Review
Independent and open review of architecture and the overall state of an existing system. I will use my experience to pinpoint strengths and weaknesses and deliver clear, tangible actions to move your system forward.
The review covers System Architecture, Code Review (quality and maintainability), and Security. Findings are presented in a meeting and delivered in writing.
Second Opinion
If you need a second opinion on an important project or are considering changes to your IT landscape, I can assist you with insights from prior experiences to help you stay on track.
Domain Driven Design Workshop
A two-day workshop where you clarify your overall project needs and design to hit the ground running when moving into feature development.