Free Invoicing & Accounting Software for Germany

BusinessOS ist die kostenlose MwSt Rechnung Software für Freiberufler, Kleinunternehmer und Kleinbetriebe in Deutschland. 19% MwSt (Umsatzsteuer), 7% ermäßigter Satz, Kleinunternehmerregelung, USt-IdNr Felder, EUR Währung — alles integriert. Free during limited early access.

BusinessOS is free accounting software Germany freelancers use for daily invoicing (Rechnungsstellung). It handles MwSt Rechnung software needs — automatic VAT calculation, sequential invoice numbering, and Belastungsanzeige-ready PDF exports — without a monthly Abonnement.

German tax compliance features

• 19% MwSt (VAT) standard rate, 7% reduced rate
• Kleinunternehmerregelung support (no VAT for small businesses under €22,000)
• USt-IdNr field for buyer and seller
• EUR (€) currency formatting
• Rechnung format meeting §14 UStG requirements
• Sequential invoice numbering
• CSV export for tools like DATEV, Lexoffice, or sevDesk

Cities and regions served

BusinessOS works everywhere with an internet connection to sign up — and fully offline after that. Currency, tax, and language settings adapt to your location. Popular cities:

• Berlin
• München (Munich)
• Hamburg
• Köln (Cologne)
• Frankfurt am Main
• Stuttgart
• Düsseldorf
• Leipzig
• Dortmund
• Essen
• Bremen
• Dresden
• Hannover
• Nürnberg (Nuremberg)
• Duisburg

Built for these businesses

• Freiberufler (freelance consultants, designers, developers)
• Kleinunternehmer (small business owners)
• Marketing- und Werbeagenturen
• E-commerce merchants
• Cafés, Restaurants, and Gastronomie
• Einzelhandel (retail shops)
• Handwerker (tradespeople)
• Coaches and Berater
• Photographers and creative professionals
• Solo legal and medical practices

Complete feature set

• Unlimited invoices and quotations
• One-click quote-to-invoice conversion
• Expense tracking with receipts
• Customer CRM with pipeline and trust scoring
• Product and inventory management
• Cash flow forecasting and tax set-aside
• P&L, balance sheet, and tax reports
• Multi-currency with automatic conversion
• Voice invoicing (English + Arabic)
• One-tap WhatsApp send on every invoice
• PDF export with your branding
• Zero-knowledge encryption
• Works fully offline
• Installs as a native app on any device

Privacy first

BusinessOS stores your data with zero-knowledge encryption. Everything is encrypted on your device with AES-GCM using a key derived from your password. If our servers are ever breached, an attacker only gets encrypted noise — not your revenue figures, customer list, or bank details.