avanton Kontor · documents and bookkeeping

Invoicing software with e-invoicing, cash book and DATEV export

Invoices a German tax auditor accepts without a word.
No subscription.

Nine document types, ZUGFeRD and XRechnung, a cash book and the monthly DATEV package — on your own server, with your number ranges and your chart of accounts.

Is this right for my business?See all features

Why we built avanton Kontor

An online shop does not write invoices. Our own shop needed a back office — and we found that between “an invoice from a word processor” and “inventory software for twenty people” there is little that fits a small business.

  • Invoicing services on subscription, with your documents sitting in someone else’s data centre.
  • E-invoicing: in German business-to-business trade, ZUGFeRD and XRechnung are not optional any more — and few small programs handle them.
  • A cash book the tax office accepts, instead of a spreadsheet whose rows can be changed afterwards.
  • A DATEV export the accountant can import without asking questions.

What avanton Kontor does

The part of an inventory system that even a small business needs — documents, money and the handover to the accountant.

Documents

  • Nine document types: quote, order confirmation, delivery note, invoice, proforma, commercial invoice, credit note, cancellation invoice, payment reminder
  • Every follow-up document knows its predecessor — the order becomes the invoice, the invoice becomes the credit note
  • Your own number ranges with a yearly reset, issued under a lock — no duplicates, no gaps
  • PDF to DIN 5008 with punch mark, barcode and a GiroCode to scan when paying
  • German or English per document, with the matching tax note
  • Customers, articles, quotes and orders entered by hand — with quick capture from free text

E-invoicing

  • ZUGFeRD in the EN 16931 profile as PDF/A-3: one PDF that is also the machine-readable invoice
  • XRechnung 3.0 for public sector customers, including the routing ID
  • Mandatory fields are checked before sending and reported in plain language
  • The invoice goes out as a PDF by email — with a log of who received what and when

Money

  • Post payments against the document, open items with due dates in view
  • Import bank statements: CAMT.053, CAMT.052 or CSV, with duplicate protection
  • Matching suggestions by document number and amount; the rest waits for clarification
  • Cash book for expenses, deposits and withdrawals — closed off month by month

Bookkeeping and audits

  • DATEV posting batch (EXTF 700): debtor against the revenue account for each tax rate
  • Payment batch with fees kept separate, cash batch from the cash book
  • Monthly package as a ZIP: batches and document PDFs in one go for the accountant
  • SKR03 or SKR04, accounts configurable per tax case
  • GoBD data export with index and description — when the auditor arrives, it is ready
  • Document archive as PDF, findable for ten years

With avanton Shop

  • A paid order becomes a sales order, dispatch creates the invoice — to the cent from the order
  • A refund becomes a credit note, a cancellation becomes a cancellation invoice
  • The invoice goes to the buyer automatically with the shop’s dispatch email
  • Transfers are signed, repeatable and reconciled hourly; the status is visible on the start page
  • Without a shop the Kontor works just the same — then you enter the transactions yourself

Built for the tax audit

Printing an invoice is something any program can do. The difference shows when somebody wants to change it afterwards.

Traceable under GoBD

German bookkeeping rules require records that cannot quietly change. Gapless numbers, credit notes instead of deletions, documents locked once closed — enforced by the database itself, not just by the interface.

E-invoicing to EN 16931

German businesses already have to be able to receive e-invoices; the duty to issue them is being phased in. ZUGFeRD and XRechnung are built in here, not bought in.

Cash book without cash income

Deliberately only expenses, deposits and withdrawals. Anyone taking cash in Germany needs a certified security module (§ 146a AO) — a cash book without one would be a liability, not a help.

Tax cases with the right wording

Small business rule (§ 19), intra-EU supply, export and reverse charge (§ 13b) — each with the right sentence on the document and the right account in the export.

Your data stays yours

Your own server, your own database, no shared tenancy. If you leave, you get the full export and your document archive.

Your own instance, not a subscription

Set-up once, then maintenance — no tiers by document count, no per-user licences. On our server in Germany or on yours.

No Windows, no licences

Linux, Node and PostgreSQL. All free, nothing expires.

Modest requirements

2 cores, 4 GB RAM, 40 GB SSD. No server cabinet.

Set up by us

Company details, number ranges, chart of accounts and tax cases are configured by us — you start with your first document, not with an empty form.

Roles for everyday work

Administration, staff, bookkeeping and read-only. Your accountant gets an account that cannot change anything.

Passkey sign-in

Passkey or password with a second factor, trusted devices can be remembered.

Off-site backup

Encrypted nightly, kept for fourteen days, with a copy on another server.

Updates from us

Including when the e-invoicing standard or DATEV changes. That is part of maintenance.

Test mode first

Until everything is right, documents carry test numbers and do not count. You say when we switch over.

Handbook included

No tool without instructions. The handbook lives inside the application — currently in German.

What avanton Kontor deliberately is not

We would rather tell you up front what is missing than surprise you with it after you buy.

  • Built around German rules: GoBD, DATEV, § 19, § 13b, ZUGFeRD and XRechnung. For bookkeeping outside Germany it is the wrong tool.
  • No customer in daily operation yet. The Kontor is built, deployed and runs as a demonstration with sample data. You would be the first business using it — that belongs in the offer and in the price.
  • The interface and the handbook are currently German-only; documents go out in German or English.
  • Not bookkeeping in the narrow sense: no profit-and-loss statement, no balance sheet, no VAT return. The Kontor prepares everything; your accountant files it.
  • No payroll and no fixed-asset accounting.
  • No point of sale and no fiscal recording unit — and therefore no cash income in the cash book.
  • No dunning. You see open items; you write the reminder yourself.
  • No purchasing, no stock, no stocktaking. If you need stock, that is what avanton Wawi is for.
  • Connected is the avanton Shop. No marketplaces, no other shop systems.
  • One company per installation. It is not a multi-client system for tax firms.

How it starts

01 — Conversation

Is it a fit?

One hour: how many documents a month, which tax cases, who does the books today, and whether a shop is attached. If your accountant already does all of it, we say so.

02 — Setup

Your numbers, your accounts

Server, company details, number ranges, SKR03 or SKR04, tax cases and access — agreed with your accountant.

03 — Test mode

Practise before it counts

The first documents run with test numbers. Your accountant imports a trial export before it gets serious.

04 — Switch over

From here it counts

Test mode off, number ranges set to the agreed start. From the first real document the chain runs gapless.

Also from the studio

avanton Wawi

Inventory management for used-goods and industrial traders — from purchase to e-invoice.

View avanton Cockpit

eBay management for multiple accounts — prices, competitors, buyer messages, fees.

View avanton Shop

Online shop with German consumer law built in — your own instance, no plugins, no revenue share.

View

Would this suit your business?

Tell us briefly how many invoices you write each month and what you use today. We will reply with an honest assessment — even if it is “probably not”.

hallo@avanton.de

Pricing on request — one-off setup including data import, then maintenance and updates as a monthly fee.