Product & Platform Architecture
I am not interested in features on their own. I care about the places where a product gets easier or harder later: boundaries, permissions, interfaces, and operations.
Senior Software Developer / Product Architect
Daniel Retzl develops systems at the intersection of audio, AI, and web infrastructure.
I work on products where frontend, backend, operations, and product decisions affect each other. I sort out the structure early and stay close to the build so the result later holds what I promise.
- Enterprise e-commerce and modernization in live systems
- Audio products, plugins, and browser-based workflows
- AI-supported delivery with technical ownership
Selected organizations
Professional background and project contexts
Schrack Technik, CANCOM, Kapsch, ISHAP, ÖGB/ÖGJ
Profile
Profile at a Glance
I am a Senior Software Developer and Product Architect with long-standing experience in web applications, enterprise e-commerce, interfaces, infrastructure, and technical ownership.
I am strongest in environments where software is not only built, but also operated, extended, and understood over time. Application logic, APIs, data, permissions, hosting, performance, and product decisions belong together in my work.
Relevant roles
- Senior Software Developer
- Product Architect / Platform Architect
- Business Application Manager
- Application / Platform Engineer
- Technical Product Owner
- bridge between business, development, and operations
What I bring
- technical ownership from concept to operation
- experience with enterprise web systems and live modernization
- understanding of APIs, databases, and interfaces
- hosting, Linux, and operations awareness
- structured requirements analysis
- pragmatic implementation with maintainability in mind
Current Focus
These are the areas I keep coming back to.
In practice they overlap. Product questions, system design, audio workflows, and infrastructure belong together.
Audio & Music-Tech
Audio is not a side track for me. I work on playback, session logic, plugin ideas, and tools shaped around real studio workflows.
AI-Accelerated Delivery
AI helps with speed in research, prototyping, and routine work. I do not only use chat interfaces, but also work with LLM-supported workflows, agents, API integration, and server-side test environments. The calls on architecture, quality, security, and integration still sit with me.
Web Infrastructure & Systems
A website is never just a website. Hosting, deployment, APIs, access, and the part that has to stay steady at night all matter.
Skills
Skills & Technical Focus
My work sits at the intersection of development, architecture, operations, and product logic. I come from web development, but I think strongly in systems, interfaces, and long-term operation.
Backend & Architecture
- PHP 7/8, OOP, and procedural legacy systems
- MySQL / MariaDB
- REST APIs, web services, middleware
- refactoring and modernization of existing systems
- roles, permissions, and access concepts
- maintainability, performance, and technical structure
Frontend & Web
- HTML5, CSS3, JavaScript ES5 / ES6
- jQuery, AJAX, Vanilla JS
- Bootstrap and responsive UI implementation
- TypeScript, React, and Tailwind in current projects
- browser-based workflows and product-oriented interfaces
Infrastructure & Operations
- Linux, Debian, Ubuntu
- Apache, nginx, web server and hosting setups
- Bash, cron jobs, automation
- deployment, operational awareness, and technical ownership
- Git / GitHub
- Docker and CI/CD basics
Interfaces, Data & Integration
- API integration and interface logic
- data models and database work
- OAuth / authentication concepts
- performance, caching, CDN, and optimization
- security, SSL, data protection, and access control
Working Style & Tools
- requirements analysis and technical concept work
- documentation and structured handover
- Jira, Confluence, Scrum / agile workflows
- collaboration with business teams, customers, and external partners
- second-level-style analysis and troubleshooting
- AI-supported research, prototyping, and delivery with technical control
AI Systems, Agents & Emerging Technology
- hands-on work with LLMs, AI-supported development, and agentic workflows
- own agent setups in controlled server-side test environments
- technical evaluation of AI tools beyond simple chat usage
- work with prompting, context design, tool use, and domain-specific workflows
- audio-related AI experiments around stem separation, voice tools, and workflow automation
- concept work for an agentic hosting product focused on administration, permissions, security, and operational logic
- careful handling of limits, failure modes, data protection, and human control
Application & Business Focus
- operation and further development of existing applications
- translation of business requirements into technical solutions
- stability, performance, and process improvement
- interfaces between software, users, and operations
- cost-benefit thinking from long-term self-employment and entrepreneurship
Selected Work
A few projects that show what my work looks like now.
Not a full archive. Just the work that is current, live, or already taking shape.
What it is: A self-hosted platform for audio sessions with customer access, playlists, playback, and clear role logic.
Why it matters: This is not a showpiece site. It has to work as an operational product where media flow, permissions, and day-to-day use all line up. The product is live in production use.
My role: I define the product logic, system structure, and access model, set the technical direction, and own implementation and smooth operation.
What it is: A browser-based audio workflow built on APIs around stem separation, voice tools, LLM-supported audio processing, and DAW-adjacent automation.
Why it matters: The interesting part is not the AI feature on its own. It is whether the whole thing becomes a tool people can actually work with.
My role: I connect product concept, workflow design, API integration, and AI-supported audio experiments. The point is not the AI effect itself, but whether it can become a reliable tool for real workflows.
What it is: Internal plugin concepts, mostly around tuner and modulation tools, with a possible path toward commercial releases later.
Why it matters: With tools like these, the idea itself is not enough. What matters is whether it actually works with the required precision.
My role: I shape the use case, the interaction logic, and the technical frame before any of it turns into a product.
What it is: The live public website karlhorak.com, which makes current execution quality visible without much explanation.
Why it matters: One of the first completed projects in 2026: the main feature is the audio player, which is used productively and intensively by many users every day.
My role: I handled the technical build from structure through frontend and brought it to production standard.
What it is: A substantial band website with an AI-supported agent for ongoing operations. A project currently in active implementation. The agent is intended as a controlled operational assistant: recurring tasks, content maintenance, structure, and editorial support should become easier without handing over technical or content control.
Why it matters: A real-world example of a working custom solution that uses modern tools while still remaining stable.
My role: From concept into reality. I stay close to the product, make technical structure decisions, and make implementation possible from prototyping to go-live.
What it is: An internal direction for a stable hosting control panel around Linux servers, websites, and administration workflows. In the longer term, this also points toward an agentic hosting product: recurring tasks such as analysis, configuration, checks, and structured admin workflows should be supported by AI, but with clear permissions, logging, and human approval.
Why it matters: What interests me here is the control layer: permissions, overview, recurring tasks, and making administration work without chaos.
My role: I plan the entire model behind the interface, from the RBAC permission system to the admin workflows.
Vita
Vita in Brief
2024 - 2025
Schrack Technik GmbH
PHP Senior Software Developer in an enterprise e-commerce environment. Work on a large webshop platform with 18 country instances, API development, refactoring, and PHP modernization from PHP 5 to PHP 8.2 in a live system.
2023 - 2024
Kapsch / K-Businesscom / CANCOM
Senior Software Developer in custom solutions. Focus areas included hosting, servers, DevOps-adjacent work, web applications, technical support, and operations.
2021 - 2023
ISHAP Softwareentwicklung GmbH
Full Stack Web Software Developer focused on PHP, JavaScript, and web applications.
2003 - 2025
goodconnect IT Services e.U.
Self-employed work in web, software, and custom solutions. Delivery of many projects of different sizes for SMEs, organizations, and larger customer environments.
2014 - today
Bigfield Tonstudio & Audio Services
Audio, studio, and product work with technical ownership. Today this is especially relevant at the intersection of audio workflows, software, web technologies, and internal product ideas.
YaWK / yawk.io
Own CMS/web kit
Own CMS/web kit with module and plugin architecture, developed over many years and used as the basis for numerous websites. Documented pre-AI legacy work on GitHub.
How I Work
I sort out the system first. Then I build.
I am most useful when the work is not just about a screen, but about what should be built, how it fits together, and what has to hold up once people actually use it.
Before the build starts
I clarify the problem, the boundaries, the interfaces, and the operating model early. That saves expensive churn later.
Structure that lasts
Shipping fast matters. So does having a structure that does not fall apart after the second release.
Product and system belong together
User flow, API contracts, data, permissions, and infrastructure are usually the same conversation. I treat them that way.
AI is a tool
I use AI where it genuinely adds speed. I do not hand off architecture, quality, integration, or final judgment.
Background
What my work is built on.
I have worked on enterprise e-commerce systems across 18 country instances. That included PHP modernization, API integration, performance work, and the less glamorous question of how a live system stays maintainable.
I host my own sites and client sites in a virtual datacenter setup. That means I naturally think about operations, reliability, access, and what happens after launch.
YaWK was a long chapter and it mattered. It teaches you a lot when you carry a system over years instead of shipping a release and moving on.
Audio and studio work sharpen my product judgment. Signal flow, interaction, responsiveness, and technical detail all have to work together.
This mix of development, operations, infrastructure, product work, and entrepreneurship is why I do not see technical roles as implementation only. I care whether a system works in day-to-day use, remains maintainable, and is usable for people who did not build it themselves.
Emerging technologies interest me when they become practically useful. With AI and agents, I am less interested in the next hype term and more interested in how such systems can be integrated safely, operated with control, and connected to real workflows.
Contact
If the topic fits, I am open to a conversation.
That includes product architecture, platform work, audio, music-tech, and roles where technical responsibility is part of the job and not an afterthought.
I am open to conversations around software development, product and platform architecture, application ownership, interfaces, web infrastructure, and technical responsibility.
Relevant conversations
- Product architecture and system design
- Platforms, hosting, and operational questions
- Audio, plugins, and music-tech products
- AI-supported execution with clear ownership
Direct contact
- Email danielretzl@gmail.com
- LinkedIn linkedin.com/in/danielretzl
- Phone +43 676 9094197
- Location Austria