Honestly: for months, we've been getting the same three questions over and over again. „Am I even affected by the e-invoicing obligation?” „XRechnung or ZUGFeRD – what do I take? And in the end: ”This route ID that's on the official order – is it even correct?„
Instead of answering these questions for the hundredth time in calls, webinars, and email threads, we sat down at the whiteboard and built three free tools. Online, in the browser, no login required. Nothing goes to our servers. Here's the overview.
Tool 1: The Duty Checker
Five questions, then you'll know. Are you based domestically? Small business owner? Revenue last year? Who are your customers? Can you receive e-invoices?
At the end, you'll receive an assessment with an urgency level – from „everything's relaxed” to „you should have started yesterday.” This includes information on the specific deadlines that apply to you and a PDF export to take with you or forward. Practical for managing directors who want clarity, for tax advisors who need to categorize clients, and for accountants who need to know exactly what needs to be done now.
Tool 2: The Format Decider
XInvoice or ZUGFeRD is a question that an honest consultant would initially answer with „it depends.” But precisely for that „it depends” we made the tool.
Four questions about customer structure, degree of digitalization, and your priorities – at the end, there's a concrete recommendation. Including pros and cons, possible special cases like Factur-X or Peppol, and concrete next steps. Small bonus: The tool can also say „take both.” Sometimes, the hybrid approach is indeed the most honest answer.
To the Format Decision Maker →
Tool 3: The Routing ID Checker
This is our favorite tool because it answers technical questions in a technically sound way. Do you have a routing ID on your official order? Type it in, and the tool will check the format and check digit according to KoSIT Specification 2.0.2 – mathematically using the Modulo 97-10 method. The same method used for IBANs, if that reassures you.
If the check digit is incorrect, the tool suggests the correct one. This way, you immediately know if you're on the wrong track or if you need to get back to the client because their ID has a typo. This saves a phone ping-pong that would otherwise often cost three days of processing time.
What all three have in common
All calculations run exclusively in your browser. No registration, no data transfer to our servers, no tracking. Sensitive data such as route IDs also remain local to your device. We didn't build it this way for PR reasons, but because we ourselves don't want to temporarily store any third-party authority data anywhere. It's simply cleaner that way.
The logic is based on the official specifications: BMF letter of October 15, 2025, KoSIT specification Leitweg-ID 2.0.2, XRechnung 3.0.2, and ZUGFeRD 2.4 (as of 2026). As soon as something important changes, we will update the tools accordingly.
And now?
Try out the tools, send them to colleagues who always ask the same questions, and let us know if you're missing anything. If you're missing a fourth tool in the toolbox – a PEPPOL ID validator, perhaps, or an archiving check? – send us an email. We're collecting ideas for the next round.
You can find all three tools clearly laid out on our Tool Page. If you want to delve deeper into the topic afterwards – keywords CICS, CBCS, Integration into your SAP – does the path lead directly on to E-Invoice in SAP.
