Founder and operator of b2bkartei.de. Writes the articles on this website about company data, public registers and the rules for contacting businesses.
Who is behind b2bkartei.de
b2bkartei.de is run by Martin Adamec as a sole trader based in the Czech Republic. Behind the content, the choice of data sources and the replies to requests is a specific person who can be found in a public register – not an agency.
Company identification number (IČO)
19552319
Legal form
Sole trader, registered in the Czech Trade Register
In business since
24 July 2023
Address
Mírová 1541, 516 01 Rychnov nad Kněžnou, Czech Republic
The articles on b2bkartei.de revolve around one question: how do you work with data about businesses in a way that is both lawful and practical? They describe where company data comes from, how to check it and where the legal limits of outreach lie.
The principle: give figures with a date and source, say openly what is not known, and do not round in our own favour. How we work is described on the page Data sources and methodology, the current scope on the page Data inventory.
German Commercial Register and Company Register: Which Data Is Public11 October 2026 – Retrieval has been free of charge since August 2022. What the German commercial register contains, what it lacks, who is not registered at all – and why only individual retrievals are allowed.
WZ 2008: Using Industry Codes for Target Group Lists11 October 2026 – How the German classification of economic activities is structured, why “skilled trades” and “online shop” have no code, and what changes with WZ 2025.
GDPR and B2B Outreach: What Applies When Contacting Czech Companies9 October 2026 – What sales and marketing teams need to know about contacting Czech companies lawfully – GDPR legitimate interest, Czech Act 480/2004 and the line between company data and personal data.
VAT Payer Reliability in Czechia: What You Must Know18 September 2026 – Buying from Czech suppliers? An invoice from an “unreliable VAT payer” can make you liable for their unpaid VAT – here is how to protect yourself.
