Thomas Karner
Custom software development
Creation of secure and maintainable web applications, APIs and backend systems. From concept to operation.
Software engineering & information systems management · Vienna
Software and digitalisation that make sense.
I'm Thomas Karner, a software engineer with a background in information systems management. I build custom software and digitalise business processes – from the first idea to running in production.
- Professional software development since 2020
- Java · Go · TypeScript
- Vienna & surroundings · remote
Services
How I can help
Digitalising business processes
Understanding workflows, digitalising them sensibly and replacing paper, spreadsheets and manual steps with end-to-end processes is information systems management in practice.
PDF/A & long-term archiving
Validation, conversion and archiving of documents as PDF/A – built on my own open-source Go library.
Something else in mind?
Tell me about your project – I'll tell you honestly whether and how I can help.
Open source · Flagship project
gopdfrab: PDF/A verification and conversion in pure Go
A fast, dependency-free alternative to Java-based tools: library, CLI and WebAssembly build for checking and converting documents to PDF/A-1b. Listed in Awesome Go. Free under the AGPL 3.0, or with a commercial licence for closed-source products.
$ go get github.com/voidrab/gopdfrab 204/204
Isartor test suite passed
569/569
veraPDF corpus passed
159
checks in 11 groups
0.27 s
for the whole 773-file corpus
Experience from projects in
- Notaries & deed archives
- Cash registers & fiscalisation (AT/DE)
- Software teams & product development
Process
How we work together
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01
Initial call
30 minutes, free: we clarify your goal, starting point and constraints.
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02
Proposal
You get a clear proposal with scope, timeline and cost.
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03
Delivery
Development in short iterations – you see results early and often.
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04
Operation
Handover, documentation and, if you like, maintenance and further development.
Hi there!
I'm Thomas Karner – nice to meet you!
I have been developing software professionally since 2020: legally compliant fiscalisation solutions for cash registers in Austria and Germany, high-security applications for the Austrian notary profession and my own products around PDF documents.
With a master's degree in information systems management, I combine solid software engineering with an eye for your business processes: I first understand how your business works – and then build software that fits.
View my CV →From the blog
All posts →-
voidrab: two web tools for working with PDF documents
The PDF Co-Viewer for reviewing documents together and the PDF Pattern Matcher for checking large batches of documents against each other – how they work and what they are for.
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RAG in business: how language models work with your own knowledge
What retrieval-augmented generation (RAG) is, which weaknesses of language models it addresses, and what companies should consider around data protection and roll-out.
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From Activiti to plain Java: when a process engine stops paying off
We moved three BPMN processes off an outdated Activiti engine and reimplemented them in Java. A field report on approach, effort and lessons learned.
Let's talk about your project.
In a free initial call we clarify what you need and how I can help – no strings attached.