Andreas Grill · Software architecture · Vienna & remote

Your requirements.Straight into software.

I design architectures in which the language and workflows of your business show up directly in the code. The domain model becomes the specification for development teams and AI agents.

Book an intro callSee focus areas
  • 20+ years of software development
  • 10 years of event‑driven architecture
  • iSAQB® CPSA-F
  • Domain‑Driven Design & arc42

Focus areas

What I specialise in

Event-Driven Systems

Systems that record what actually happened in the business, instead of only reflecting the current state. I model workflows together with domain experts and developers (with Event Modeling or EventStorming, for example) and implement them with Event Sourcing and CQRS. I have worked with the Axon Framework since 2016, from the initial architecture through operation and further development over many releases. On one project we even generated the code straight from the event model.

  • Event Modeling
  • Event Sourcing
  • CQRS
  • DDD
  • Axon Framework
  • Kafka
  • NATS
  • MQTT
  • AsyncAPI
  • Code generation

Identity, Access & Security

Who may do what? And who did what, when? Since 2016 I have built security-relevant software for electronic locking and access control systems: role and permission models, Keycloak connected to Active Directory, OpenID Connect and SAML. Plus audit logs built on event sourcing: immutable, replayable to meet new audit requirements retroactively, and GDPR-compliant thanks to crypto shredding.

  • Keycloak
  • OpenID Connect
  • OAuth 2.0
  • SAML
  • Single sign-on
  • Active Directory
  • Role models
  • Access control
  • Audit log
  • Crypto shredding

Traceable Architecture

Software only stays maintainable if, years later, it is still clear why it was built the way it is. I record architecture with arc42 and architecture decision records, and the domain model describes, in the language of the business, what the system is meant to do. New team members find their way by it just as AI agents do. That way they work within the architecture instead of around it. And where AI belongs in the product itself, I integrate language models into existing architectures, with an eye on data protection and the EU AI Act.

  • DDD
  • arc42
  • ADRs
  • Spec-Driven Development
  • Agentic Coding
  • LLM integration
  • EU AI Act

Approach

From the first conversation to the hand-over

Good architecture emerges step by step, together with the people who understand the business. This is what working with me typically looks like:

  1. Step · 01

    Domain understood

    In workshops using methods such as Event Modeling, EventStorming or Domain Storytelling, we work out together with the business what the system has to do and where its boundaries lie.

  2. Step · 02

    Architecture designed

    From that comes a sound architecture, recorded with arc42 and ADRs. The resulting model serves as the specification for teams and AI agents.

  3. Step · 03

    System built

    Depending on what you need, I work hands-on and build the critical parts myself. Alternatively, I support your team, explaining concepts, building prototypes and being there when questions come up.

  4. Step · 04

    Team enabled

    Mentoring, pairing and documentation keep the knowledge in your team, so the software can be developed further independently.

Services

How we can work together

Start with a clearly scoped engagement, or bring me into your team for a longer stretch.

  • Workshop

    Modelling & architecture review

    A clear picture within a few days: we model your workflows together with the business. Alternatively, I review your existing architecture including security aspects and record the findings and prioritised improvements in arc42.

  • Enablement

    Spec-driven development

    Domain models and ADRs as guard rails, so your team can work reliably with AI agents. As a next step, code can be generated directly from the event model.

  • Ongoing

    Interim architect or tech lead

    I join your team for several months, on site in Vienna or remotely.

Projects

Selected projects

Projects I shaped as architect and developer.

Security technology · 2016–2026

Software for an electronic locking system

New development and many years of further development of the management software for an established electronic locking system. A central challenge was making permissions and access events traceable in an audit-proof way.

With Event Sourcing and Axon, the system models not just the current state but the complete business history as an immutable chain of events. As a result, new audit-log requirements could be met even years later by replaying existing events, without ever having to alter historical data.

The system also covers device communication over MQTT and an Android app with Bluetooth LE. In a follow-up project, a multi-tenant application with a user-centred interface and crypto shredding for erasing personal data was built under my architectural and technical lead.

My role: Architecture, development, mentoring, proxy product owner

  • Axon Framework
  • Event Sourcing
  • Crypto Shredding
  • Spring Boot
  • React
  • MQTT
  • Vault

Architecture · 2026

Architecture concept for a distributed system across several sites

A company needs a system that keeps working on its own when the connection between sites is down, while securely synchronising data between several network zones. Separating the operational network, the DMZ and an area accessible only to public authorities was of particular importance.

The resulting architecture lets every site operate autonomously. Relevant business transactions are captured as events and synchronised between sites via encrypted event streaming. Each site stays operational when the connection drops, and the relevant data can be synchronised once it is restored.

Operations are planned on Kubernetes and GitOps.

My role: Architecture concept

  • Event Sourcing
  • MQTT
  • Kubernetes
  • ArgoCD
  • Keycloak
  • OpenBao
  • PostgreSQL

Hospitality · 2025–present

Booking platform with digital access

Guests book accommodation through a mobile app and pay with credits. A central business challenge is linking the booking to physical access: the first successful door opening marks check-in, and access rights expire automatically after check-out.

The workflows were described together with the business using Event Modeling, and the architecture was derived from them on the basis of Event Sourcing. Development proceeds incrementally with the team I built.

My role: Architecture, team building, mentoring

  • Event Modeling
  • Axon Framework
  • Kotlin
  • Spring Boot
  • Keycloak
  • Angular
  • Capacitor
  • Kubernetes

Product information management · 2023–2024

AI-assisted content generation for a product information management system

An existing product information management system was extended with automated, AI-assisted generation of product texts and other content. To that end, a cloud-native microservice architecture with event streaming and dynamic scaling was designed and implemented.

The solution was developed by a six-person international team.

My role: Architecture, development lead

  • Kotlin
  • Spring Boot
  • NATS
  • Kubernetes
  • Vault
  • Grafana
Portrait of Andreas Grill

About me

Andreas Grill

I have been developing software for more than 20 years and have held almost every role between code and architecture along the way. I started as a developer and later worked as tech lead and architect.

I am at my best where business and technology meet: working out what actually happens in a system, who is allowed to do what, and how to build it so that it still makes sense ten years from now. My foundation is Domain-Driven Design and arc42. On top of that come techniques such as Event Modeling and EventStorming, plus a healthy dose of pragmatism.

With EmberBytes IT I offer this experience as an independent consultant. We can work together on site in Vienna or remotely. I also enjoy sharing it in talks, for example at the Java Vienna Meetup or the EventSourcing Vienna Meetup.

Contact

Tell me about your project

Drop me a short note on what it's about, and we'll set up a no-obligation intro call.

Send email

office@emberbytes.atLinkedIn