MP Rechnungen — Invoicing software for Austria
Invoice. Send. Paid. The free invoicing software for sole traders, freelancers and small businesses in Austria, developed and operated by me.
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Free plan to start
§ 11
UStG-compliant
3
E-invoice formats
Background
Many sole traders, freelancers and small businesses in Austria still write their invoices in Word templates and keep an Excel list on the side. What was the last invoice number? Is the VAT correct to the cent? Has the client paid yet? If a mandatory detail under § 11 UStG is missing, the client cannot reclaim input VAT. Existing tools are often expensive, bloated or not tailored to Austria.
Challenge
Invoicing software has to be legally watertight: mandatory details under § 11 UStG, immutable invoices under § 131 BAO, retention under § 132 BAO, reverse charge for EU clients and e-invoicing according to EN 16931. At the same time it has to work on desktop and phone without training, strictly separate data between accounts, run GDPR-compliant in the EU and be operated profitably as a SaaS with plans and online payment.
Solution
MP Rechnungen is a multi-user SaaS built on Nuxt 4 and Supabase, which I developed myself from the idea through to operation. Choose a client, enter the service, send: number, date, tax and due date are set automatically. Every invoice carries a payment QR code, is sent from your own SMTP mailbox and is stored immutably in the archive. Plans, limits and Stripe subscriptions live dynamically in the database and are enforced directly via database triggers and row level security.
Results
- Live at rechnungen.mporg.at, free to start without a credit card
- Every mandatory detail under § 11 UStG has its own field, none gets forgotten
- Issued invoices immutable under § 131 BAO, archive as PDF/A-3 with SHA-256 hash chain
- E-invoicing in three formats: ZUGFeRD/Factur-X, XRechnung 3.0 and ebInterface 6.1
- Recurring invoices create and send themselves automatically
- Self-sign-up, Free and Business plan with Stripe subscription, fully automated
All features
Invoices & documents
- Invoice, fee note and credit note referencing the original
- Recurring invoices: weekly, monthly, quarterly or yearly, billed in advance or in arrears
- Created automatically as a draft for review or sent directly, service period filled in
- Sequential invoice numbers, can be set manually if needed
- Net, VAT and total to the cent, including mixed 20, 13 and 10 % rates
- Reverse charge for EU businesses with 0 % VAT and the mandatory note
- Small business scheme with 0 % VAT and exemption note
- Payment terms per client, due date printed on the invoice automatically
Law & standards
- All mandatory details under § 11 UStG, including VAT IDs and service period
- Immutable under § 131 BAO: issued invoices are locked in the database
- Invoice archive under § 132 BAO: PDF/A-3 (+ XML) with SHA-256 hash chain, archive verification, ZIP download per year
- E-invoice per client: ZUGFeRD/Factur-X (EN 16931), XRechnung 3.0 and ebInterface 6.1 for e-rechnung.gv.at
- Address field according to DIN 5008 form A, fits a window envelope
- EPC payment QR code with IBAN validation and invoice number as payment reference
Sending & design
- Sending via your own SMTP mailbox (STARTTLS or SSL/TLS), clients reply directly to you
- Optional copy to your tax advisor
- Delivery log per invoice and automatic retry on errors
- Own logo and invoice templates with live PDF preview
- PDF download of every invoice
Overview & clients
- Dashboard with monthly revenue, open and overdue invoices
- Filters for drafts, open, overdue and paid invoices
- Mark as paid with one click
- Client management for companies and individuals, multiple addresses, automatic client numbers
- Runs in the browser on desktop, tablet and phone, no installation
Security & GDPR
- Sign-in via password, magic link or passkey, two-factor authentication (TOTP)
- Captcha protection against automated sign-in attempts
- TLS for every connection, SMTP passwords encrypted with AES-256-GCM
- Database in the EU, row level security: every account sees only its own data
- Data export as PDF archive, CSV and JSON, account deletion at any time, DPA included
Plans & operation
- Free: 25 invoices per month, no credit card and no time limit
- Business: unlimited invoices, e-invoicing and priority support, monthly or yearly
- Payment via Stripe with card, Apple Pay or Google Pay, cancel any time
- Super admin area with dynamic plans, user management and audit log
Technology
Similar project to discuss?
30-minute initial consultation — free, non-binding, concrete.