OliverDirr
Senior Software Engineer · Team Lead
Software architecture, Domain-Driven Design and payment infrastructure for large‑scale platforms.
About Me
I am a software engineer and technical leader with a background in Business Information Systems and a strong interest in solving complex problems through software.
I started my career at CHECK24 as a working student and gradually moved into backend engineering, software architecture and technical leadership. Over several years, I worked on the architecture of CHECK24’s rental car platform, where I contributed to Domain-Driven Design, domain modeling and the definition of domain boundaries. This experience shaped the way I approach software: I am interested not only in how to implement a feature, but in understanding the underlying business problem and designing systems that can evolve with it.
As a Senior Software Engineer, I have worked on business-critical payment systems and taken ownership of complex areas including payment architecture, external payment providers, internationalization and accounting. I have been involved in onboarding providers such as Revolut, Stripe, Apple Pay and PayPal and in building software connecting rental car bookings, payments, settlements and accounting.
Since January 2026, I have also been Team Lead of the Pay Team. My responsibilities now combine technical leadership with people management, roadmap planning, prioritization and cross-functional stakeholder management. I work on both sides of engineering leadership: making technical decisions and creating the conditions for other engineers to work effectively and take ownership.
What I enjoy most is bringing structure to complex problems. I like understanding the domain, challenging assumptions, discussing different approaches and turning that understanding into software that remains understandable and maintainable over time.
I believe good engineering is about more than writing good code. It requires ownership, clear communication, thoughtful architectural decisions and the ability to balance technical quality with real-world constraints.
Career
Professional experience across engineering, architecture and technical leadership.
CHECK24 Mietwagen
Augsburg, Germany
- Jan 2026 – PresentTeam Lead — Pay Team
- Oct 2025 – PresentSenior Software Engineer
- Oct 2023 – Sep 2025Professional Software Developer
- Jun 2023 – Sep 2023Junior Software Developer
- Mar 2022 – May 2023PHP Backend Developer
- Apr 2022 – Apr 2023Working Student — PHP
- Sep 2021 – Mar 2022Working Student — Project Management
Architecture & Software Engineering
- Contributed to the fundamental architecture of CHECK24’s large-scale rental car platform.
- Applied Domain-Driven Design to model complex business domains and establish meaningful domain boundaries.
- Drove and participated in domain discussions to translate complex business requirements into sustainable software architecture.
- Worked on architectural decisions spanning rental car, payment, settlement and accounting domains.
- Designed and developed business-critical backend systems with a focus on maintainability, reliability and long-term evolvability.
- Worked extensively with PHP, Symfony, Doctrine, MySQL and asynchronous messaging.
- Contributed to the evolution and modernization of CHECK24’s payment architecture.
Payment Infrastructure & External Integrations
- Led the technical integration and onboarding of international payment providers and payment methods, including Revolut, Stripe, Apple Pay and PayPal.
- Integrated external payment providers into CHECK24’s payment architecture and handled the associated technical and domain requirements.
- Worked on payment authorization, payment execution, supplier settlement and accounting-related processes.
- Contributed to payment architecture supporting multiple payment methods, providers and markets.
- Worked on the internationalization of the rental car and payment platform, adapting systems and domain concepts to different markets and country-specific requirements.
Financial & Accounting Systems
- Drove the development and introduction of a new accounting system for rental car settlements.
- Coordinated technical requirements across engineering, accounting and business stakeholders.
- Designed solutions for complex financial processes connecting bookings, payments, settlements and accounting.
- Translated business and accounting requirements into technical solutions and negotiated cross-functional trade-offs.
Technical Ownership & Production Engineering
- Take responsibility for the stability and continuous evolution of business-critical payment systems.
- Investigate and resolve production issues involving CPU, memory, storage, databases, queues and application performance.
- Work across the complete service lifecycle, including development, testing, deployment, monitoring and production operations.
- Secured the parallel operation of legacy and new payment systems.
- Contributed to the Jenkins migration and advanced the Pay-Core architecture.
- Drove modernization initiatives across the payment platform.
- Developed and promoted internal engineering initiatives including Pay MCP and the Pay Hackathon.
- Maintain a strong focus on system reliability, operational stability and sustainable technical solutions.
Team Leadership & People Management
- Lead the Pay Team with approximately five engineers and hold technical and disciplinary responsibility.
- Conduct feedback and development conversations and support engineers in increasing autonomy and ownership.
- Handle critical conversations and complex personnel situations.
- Provide orientation and stability to the team during difficult situations.
- Foster team motivation, collaboration, knowledge sharing and individual responsibility.
- Translate organizational goals into clear expectations, priorities and actionable work.
- Balance team capacity, technical quality, reliability and business priorities.
Product & Organizational Leadership
- Translate management objectives into actionable engineering priorities and roadmap decisions.
- Actively plan and represent the engineering roadmap.
- Evaluate and communicate trade-offs between technical work, business requirements and team capacity.
- Drive cross-functional initiatives involving engineering, product, accounting and business stakeholders.
- Represent engineering topics in cross-team and leadership discussions.
- Negotiate sustainable compromises for complex cross-functional initiatives.
Skills
Core technologies, disciplines and tools I work with day to day.
Backend & Languages
Frontend
Architecture & Engineering
Payments & Financial Systems
Data & Infrastructure
Observability
Engineering & Collaboration
AI & Developer Tooling
Selected Engineering Impact
A few areas where my work had lasting impact and shaped large-scale systems.
CHECK24 Rental Car Platform — Architecture & Domain Modeling
Worked for several years on a major CHECK24 rental car project and contributed to its fundamental architectural direction.
This involved designing software around a complex and evolving business domain rather than optimizing individual features in isolation.
Payment Platform — Internationalization & Payment Providers
Worked on expanding and evolving the payment platform through internationalization and external payment integrations. Key integrations included Revolut, Stripe, Apple Pay and PayPal.
Rental Car Accounting — Financial Software
Drove the implementation of a new accounting system for rental car settlements. The project required coordination between engineering, accounting and business stakeholders and involved translating complex financial processes into maintainable software solutions. The initiative is also part of the cross-functional responsibilities I took on as Team Lead.
Pay Team — Engineering Leadership
Since January 2026, responsible for the Pay Team as Team Lead. The role combines technical direction, people management, roadmap and prioritization, stakeholder management, team development, production responsibility and architectural decision-making.
DEVOLTI
Augsburg, Germany
Co-founder and developer at DEVOLTI (Dirr Oliver, Dreier Tim GbR).
- Develop software solutions independently and together with a business partner.
- Take responsibility for technical implementation and project execution.
- Work across the complete development lifecycle from requirements to implementation and delivery.
- Combine software engineering with entrepreneurial and business responsibility.
Previous Experience
CHECK24 Versicherungscenter
- Full-stack development using the MERN stack.
- Development of web applications and backend services.
- Experience working in a professional software engineering organization.
University of Augsburg
Grenzebach
Education
- Apr 2021 – Oct 2023
University of Augsburg
Master of Science — Business Information Systems
Grade: 1.42 - Oct 2017 – Jan 2021
University of Augsburg
Bachelor of Science — Business Information Systems
Grade: 2.01 - Oct 2014 – Jul 2017
Hans Leipelt Fachoberschule
General Higher Education Entrance Qualification
- Oct 2009 – Jul 2014
Realschule Heilig Kreuz
Intermediate Secondary School Certificate
Awards
Past projects
Platforms, products and systems I have designed, built or driven.
CHECK24 Rental Car Platform
Large-scale business platform with focus on domain modeling, architecture and Domain-Driven Design.
Payment Platform Modernization
Evolution of business-critical payment architecture including payment processes, external providers, supplier settlement and accounting.
3D Terrace Planner
Independent software project.
Portfolio Website
Next.js-based personal portfolio with Matomo analytics.
LEW IoT Device Registration
IoT device registration project using Oracle APEX.
Linear Optimization
Optimization project using Python and IBM CPLEX.
Master’s Thesis — Chatbot / Configuration File Graph
Academic project exploring chatbot-based interaction with configuration structures.
Languages
Interests
Let's get in touch
I am happy to talk about software architecture, payment systems, engineering leadership — or the best pizza in town. Write me a message or connect via the links below.