Software for critical infrastructure
Development and long-term maintenance of software for a regional utility company as well as a flood warning system: dependable processes for critical services.
Freelance Software Engineer · Across Germany
Custom Software Development for Your Business
I am Renick Büttner, software engineer and IT expert witness. For more than 10 years I have been building custom software, online shops and apps for mid-sized companies: remote for clients across Germany, on site in Saxony, as your direct contact without agency overhead.
From replacing manual Excel-based processes and building internal tools to complete online shops: my projects range from a regional utility company to manufacturing companies, backed by long-standing experience from enterprise software with millions of users. As an October CMS Silver Partner I maintain my own plugins on the official marketplace and, if you wish, your software in production for many years.
- IT expert witness
- 10+ years of experience
- October CMS Silver Partner
Services: software made to measure
From the first concept to day-to-day operations: all from a single source.
Custom software
Tailor-made software development for your processes: web applications, automation and specialised business tools, a precise fit instead of off-the-shelf.
E-commerce & online shops
Powerful online shops with Shopware 6: builds, migrations, plugin development and ERP integrations, including ongoing care for existing shops.
CMS & websites
Fast, maintainable websites with October CMS and full editorial freedom, as a Silver Partner with plugins on the official marketplace.
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Mobile apps
Native and hybrid iOS and Android apps with a strong backend, from the idea to the release in the app stores.
Databases & legacy replacement
Replace sprawling Excel landscapes and ageing silo solutions with modern, web-based databases, from product data to archiving measurement records.
Interfaces & integration
Develop APIs and connect systems: ERP, shop, CRM and internal tools exchange data automatically, instead of copy & paste.
Future-proof
Automation with AI
Artificial intelligence makes automation even more effective: recurring tasks complete themselves in the background, data is processed and prepared automatically, and your team focuses on what matters. Integrated into your existing systems, privacy-conscious and with clear rules for when the AI decides and when a human does.
Process & generate data
Automatically read, classify and turn documents, e-mails and forms into structured data, or have texts, descriptions and reports generated.
Decisions made by AI
The AI makes routine decisions according to your rules, such as prioritisation, categorisation or approvals, and hands edge cases over to your team transparently.
Smart automations
Workflows that think along: connect systems, detect events and automatically trigger the right follow-up steps, from the inbox to the ERP.
Pre-processing of tasks
AI prepares the work, your team decides: drafts, summaries and suggestions are ready before the actual work begins.
On-premise AI: your data stays in-house
On request we deploy AI solutions directly on your premises: language and analysis models run on your own hardware or in your private environment and can be used day to day without any data having to be sent to the cloud. Ideal for sensitive documents, personal data and industries with strict requirements.
- No data transfer to the cloud
- Full control over models and access
- Privacy-friendly, even for sensitive areas
Made-to-measure instead of off-the-shelf
Standard software forces your workflows into someone else’s mould. Custom software models the processes that actually set your company apart. Especially for mid-sized businesses this decides over saved time, data quality and happy employees.
Whether it is a sprawling Excel landscape, an ageing legacy database or a manual process with countless media breaks: a made-to-measure web application replaces isolated tools with one system your whole team can use at the same time: secure, traceable and extensible.
- Precisely tailored to your processes
- No per-seat licence fees
- Grows with your company
- Full data sovereignty with hosting in Germany
- Advice included: sound decisions on your digitalisation journey
How your project unfolds
Transparent from the first idea to operations, with short paths and early results.
Free initial consultation
Remote or on site: we discuss your plans, processes and goals, without obligation.
Concept & proposal
You receive a clear concept with a transparent effort estimate, with a prototype on request, so you see early what is being built.
Development
Implementation with rapid application development: short cycles, regular check-ins, first usable results often within a few weeks.
Operations & long-term support
Hosting, maintenance and further development from a single source. Your investment stays reliable for the long run.
Your contact
Renick Büttner, software engineer & IT expert witness
As a media informatics graduate I have built software for critical services such as regional energy supply and bring long-standing enterprise software experience: an employee platform with millions of users and a popular email marketing product for enterprise customers that I helped build from the ground up. Today I support mid-sized companies as a freelancer, advising you on the decisions along your digitalisation journey. Established partners back me up on support and communication, so you can actually reach me.
- Media informatics graduate
- IT expert witness for neutral assessments
- October CMS Silver Partner with plugins on the official marketplace
- Enterprise experience: platforms with millions of users
Reference projects
Three examples of what custom software achieves in practice. I am happy to share further references in a personal conversation.
Enterprise experience: SaaS & email marketing
Years of product development on an employee platform with millions of users as well as building a popular email marketing product for enterprise customers from the ground up.
Legacy database replacement in production
Replaced conventional database silos with a web-based application: from product data to archiving measurement records, multi-user and maintainable.
Frequently asked questions
It depends on the scope: a small internal tool costs far less than a complete online shop. After a free initial consultation you receive a concept with a transparent effort estimate, as a fixed price on request. Rapid application development keeps the effort predictable even for more complex projects.
First usable results are often ready within a few weeks. Smaller tools go live quickly, larger projects are delivered in stages. You work with the software early on and help steer the priorities.
Yes. I replace ageing database and Excel solutions with web-based applications: multi-user, with clean permission management and complete data migration from the legacy system. The transition happens step by step and without data loss.
Yes: on-site appointments are possible in Chemnitz, Zwickau, the Erzgebirgskreis and all of Saxony; my office is in Lößnitz near Aue. Beyond that I work remotely with clients across Germany.
On request I take care of hosting, maintenance, updates and further development. Many of my projects have been under my care for years. Your investment stays reliable instead of ageing after launch.
With a freelancer you talk directly to the developer: short paths, no friction, fair costs. Established partners back me up on support and communication, combining personal service with the reliability of a team.
Depending on the task: Shopware 6 for e-commerce, October CMS and Laravel for websites and business applications, native and hybrid app development, plus Go and modern databases. I choose technologies with long-term support so your software lasts for many years.
Contact: request custom software & consulting
Whether custom software, online shop, website or app: briefly describe your plans and you will receive an honest assessment, with a free initial consultation, remote or on site.
Let’s talk about your project
Free initial consultation: remote or on site. Briefly describe your plans and I will get back to you promptly.
Reach me directly Renick Büttner · Chemnitzer Str. 10A, 08294 Lößnitz +49 3771 5646920What comes out of it
Two glimpses of the work: custom software for your processes, and modern web and app projects.
Custom software
Software that fits your processes exactly
From process analysis to the finished business application: custom software digitalises workflows, connects your systems and replaces Excel silos and ageing databases.
- Internal tools
- Automation
- Databases
- Interfaces & API
Web & apps
Website, web app, online shop and native apps
From a fast website with October CMS and e-commerce with Shopware 6 to web apps and native apps: modern, maintainable and with a clean backend behind it.
- Website & CMS
- Web app
- E-Commerce
- Native app