These are the guides for the person who has to get it right on Monday: the owner writing the first invoice with two taxes on it, the freelancer wondering whether the turnover threshold has been crossed, the business leaving one piece of software for another and afraid of arriving on the other side with a number missing. Each one is written from the law and the primary sources, says what KRONENWERK does about it, and says just as plainly what it does not do. Nothing here is tax advice; every page names the point at which the question belongs with your accountant.
What an invoice has to show
A document that is wrong is not only a legal problem — it is a payment that stalls, because the customer's bookkeeper cannot claim the tax on it and sends it back. Two guides go through that in detail for the two places KRONENWERK is used most. What a Québec invoice must show sets out the CRA and Revenu Québec thresholds by amount, why GST and QST belong on two separate lines with two registration numbers, and where the Charter of the French language comes in. The mandatory particulars of a German invoice walks the § 14 Abs. 4 UStG list item by item with the trap in each, covers the small-amount invoice, and gives the § 14a wordings for reverse charge and intra-Community supplies verbatim.
Crossing a border, and crossing a threshold
Selling outside your own tax jurisdiction changes the document and sometimes the tax. Invoicing a US customer from Canada explains why most exports are zero-rated rather than untaxed, why the invoice should still carry a 0 % line with a stated reason, what the customer's W-8BEN-E request is about, and how a US-dollar invoice sits on top of Canadian-dollar books. Registering for the GST/HST takes the $30,000 small-supplier test apart: the single-quarter test and the four-quarter test have different consequences and different effective dates, and the difference decides which invoices you should have been charging tax on. The German Kleinunternehmerregelung does the same for § 19 UStG, including the part most summaries get wrong — a Kleinunternehmer may still send an ordinary invoice, but has had to be able to receive an e-invoice since January 2025.
Running the business, not just the invoice
The rest of the guides are about the work around the document. Transactions explains the job folder: quote, order, supplier bills, photos, invoice and payments under one number, with no amount of its own. Switching to KRONENWERK is the honest version of a migration — what comes across, what does not, how long it takes, and the rule that lets you reverse the whole import while no imported record has been touched. Several companies and several currencies, bookkeeping for a SaaS business, bookkeeping for a European startup and connecting your own application cover the cases that do not fit one country and one company.
How KRONENWERK handles this
SUPPORTED WITH LIMITATIONS Every guide ends with the same two paragraphs: what the product actually does about the subject, and what it does not. KRONENWERK issues invoices with several taxes on a line, checks the country's required particulars before a number is spent, freezes issued documents and corrects them with credit notes, keeps the originals with the record, and lets an accountant in. It does not file a tax return anywhere, does not decide a rate or whether a supply is taxable, does not run payroll, and gives no tax advice. Four plans from 29 € a month, listed on the pricing page; there is no free plan and no trial.
Frequently asked questions
Is any of this tax advice?
No. The guides state the rules and cite the source they came from. Applying them to your business is your accountant's work, and each page names the points where that is especially true.
How current are these pages?
Each page carries the date it was last checked and a list of the sources that were read, with their own dates. Where a rule was about to change, the page says so rather than pretending the date is settled.
Which guide should I start with?
The one that matches the document in front of you. If you are choosing software rather than writing an invoice, the comparison pages are the better starting point.
Do the guides only cover Canada and Germany?
Those two are the deepest, because they are where the product is used most. Belgium, France, Poland and the cross-border cases have their own sections under e-invoicing.
Can I check a file or a number without an account?
Yes — the free tools validate an e-invoice, check a VAT identification number and build a Peppol identifier without signing in.
The pages in this guide
- Accounting for SaaS companies in Europe: revenue, Stripe, VAT and the API How a European SaaS keeps its books: deferred revenue, Stripe payouts vs invoices, OSS and reverse charge VAT, refunds, multi-currency and what to automate.
- Accounting for startups in Europe: entity, VAT, invoicing, e-invoicing What a European startup needs from its accounting: choosing DE, FR, BE or PL, VAT registration, invoicing rules, e-invoicing mandates and an accountant.
- Multi-company, multi-currency accounting: ledgers, intercompany, FX How to keep books for several companies and currencies: one ledger per entity, intercompany invoices, exchange rates, realised and unrealised differences.
- How to connect your app to accounting software: CSV, integrations, API, MCP The four ways to connect an app to accounting software, what to sync (customers, invoices, payments), idempotency, webhooks and keeping API keys safe.
- Switching to KRONENWERK: from other software or your accountant's spreadsheet How a switch works: what moves (customers, invoices, bills, payments, files, opening balance), what does not, how long it takes, and how to keep your accountant.
- One job, every document: transactions in KRONENWERK Why the quote, purchase order, supplier bills, drawings, photos, invoice and payments of one job belong in one folder inside the accounting — and stay out of the money.
- What a Québec invoice must show: GST, QST, both numbers, French — the rules by amount Invoice rules for a Québec business: what the CRA and Revenu Québec require under $100, from $100 and from $500 — two tax lines, both registration numbers, French.
- Invoicing a US customer from Canada: zero-rated exports, the invoice, the currency How a Canadian business invoices a US customer: when GST/HST and QST are zero-rated, what the invoice shows, USD invoicing with CAD books, and proof of export.
- When do I have to register for GST/HST and QST? The $30,000 threshold The $30,000 small-supplier threshold explained: the four-quarter test, the single-quarter test, what changes the day you cross it, voluntary registration and the QST.
- Kleinunternehmer invoices under § 19 UStG: no VAT, the § 19 reference, E-Rechnung What a Kleinunternehmer invoice must show since 2025 — the 25 000 and 100 000 euro limits, the § 34a UStDV particulars, no Vorsteuer, and the E-Rechnung duty.
- What a German invoice must show: the § 14 UStG particulars, item by item The mandatory particulars under § 14 Abs. 4 UStG, the 250-euro Kleinbetragsrechnung, the § 14a statements, and what a missing one costs the recipient.