open /Applications/Pay\ Day.app

Pay Day

E-Invoice & Peppol

Invoices your tax authority can actually read

The EU is making electronic invoicing mandatory. A pretty PDF is no longer enough. Pay Day creates EN 16931 e-invoices and delivers them over Peppol, straight from your iPhone.

New on the App Store Free Business iPhone

See it in action ↓

Unlimited invoices and estimates, free
Factur-X / ZUGFeRD hybrid e-invoices
Peppol delivery into your client's system
Works fully offline, no account to start

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Pay Day in action

A finished, branded invoice
Building line items and VAT
Track invoice and payment status
Compliant e-invoice ready to send
Pro and Peppol credit packs

tap a screen to enlarge · swipe to see more → click a screen to enlarge

cat payday/FEATURES.md

What Pay Day does

The EU is making electronic invoicing mandatory. A pretty PDF is no longer enough. Pay Day creates EN 16931 e-invoices and delivers them over Peppol, straight from your iPhone.

Real VAT Engine

An EN 16931 VAT engine handles standard rates, intra-community reverse charge, zero-rated and exempt lines, with a correctly rounded breakdown on every document.

Factur-X E-Invoices

One hybrid file looks like a clean invoice to your client and carries embedded EN 16931 data a tax system reads automatically. Validated as a PDF/A-3 with valid XML.

Peppol Delivery

Send invoices straight into your client's accounting software over the EU's official network. No email attachment, no portal login.

Live VAT Validation

Check every client's VAT ID against the EU VIES service before you issue. Validation is advisory, so it never blocks a send.

Recurring & Branded

Set a recurring invoice once and get paid every month. Add your logo, accent colour, and templates that match your business.

AI Helpers, Optional

Snap a receipt into line items, draft an invoice from a description, or write a payment reminder. A few credits each, never required.

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How Pay Day works

Build

Add a client, drop in line items, and Pay Day computes the VAT breakdown and totals as you go.
Compose

Export a branded PDF for free, or generate a compliant Factur-X e-invoice with embedded EN 16931 data.
Send

Email the PDF, or deliver it over Peppol directly into your client's accounting system.

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About Pay Day

Most invoice apps make a pretty PDF. Pay Day makes one your tax authority's system can actually read.

The EU is switching to mandatory electronic invoicing — Belgium for all businesses (2026), with Germany, France (2027), Poland and more rolling out next. That means a normal PDF is no longer enough. Pay Day is built for exactly this moment, on your iPhone, with no desktop software and no monthly bookkeeping suite.

FREE, AND GENUINELY GENEROUS

- Unlimited invoices and estimates. No per-document limit, no watermark, no "upgrade to export."

- Unlimited clients, your logo, and multi-currency with European Central Bank reference rates.

- A real EN 16931 VAT engine: standard rates, intra-community reverse charge, zero-rated and exempt lines — with a correct, properly rounded VAT breakdown on every document.

- Works fully offline. Bill from a job site, a train, anywhere.

- No account required to start. Open the app and you're invoicing.

PRO — REAL E-INVOICE COMPLIANCE, NOT JUST A PDF

- Factur-X / ZUGFeRD e-invoices: a single hybrid file that looks like a clean invoice to your client and carries embedded EN 16931 data a tax authority's system can read automatically. Independently validated as a valid PDF/A-3 with valid EN 16931 XML.

- Peppol delivery: send your invoice straight into your client's accounting system over the EU's official network — no email attachment, no portal logins.

- Recurring invoices: set it once, get paid every month.

- Your branding: logo, accent colour, and templates that look like your business, not a template.

- Live VAT validation: check every client's VAT ID against the EU VIES service before you issue.

CREDIT PACKS — PAY ONLY FOR WHAT YOU SEND

- Top up with consumable credit packs that cover each Peppol network send (we pass through the real per-send cost rather than padding a subscription).

- The same credits power optional AI helpers: snap a photo of a quote or receipt and turn it into line items, type a rough description and let it draft the lines, or generate a tactful payment-reminder email for an overdue invoice. AI actions cost a few credits each and are entirely optional — the app is complete without them.

WHO IT'S FOR

Freelancers, consultants, designers, developers, and small businesses across the EU who invoice other businesses and need to be ready for e-invoicing mandates — without paying for a heavyweight accounting platform.

HONEST PROMISE

The free app is a complete invoicing tool, not a trial. We only ask you to pay where it genuinely costs us or genuinely earns you compliance: structured e-invoices, network delivery, automation, and AI. No fake urgency, no nagging, no surprise limits.

Pay Day Pro is an auto-renewing subscription, monthly or annual with a 7-day free trial. Peppol network sends are metered separately via consumable credit packs on every Pro plan. Payment is charged to your Apple ID; subscriptions renew automatically unless cancelled at least 24 hours before the end of the period; manage or cancel anytime in your Apple ID settings. Credit packs are one-time purchases.

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Frequently asked questions

Is Pay Day really free?

Yes. The free tier gives you unlimited invoices and estimates, unlimited clients, your logo, multi-currency, and the full VAT engine, with no watermark and no per-document limit. It is a complete invoicing tool, not a trial.

What does Pay Day Pro cost?

Pro is an auto-renewing subscription, monthly or annual; the annual plan includes a 7-day free trial. It unlocks Factur-X e-invoices, Peppol delivery, recurring invoices, branding, and VAT validation. You can cancel anytime in your Apple ID settings.

What are credit packs for?

Credit packs are one-time purchases that cover each Peppol network send at its real per-send cost, instead of padding the subscription. The same credits power optional AI helpers. Local PDF export never needs credits.

Does Pay Day work offline?

Yes. You can build and export invoices fully offline from a job site, a train, or anywhere. Only Peppol sends, VAT validation, and AI actions need a connection.

Where is my business and client data stored?

On your device. Your business and client data stays on the phone; the server only ever sees what you explicitly send, such as a VAT ID to validate or an invoice to transmit over Peppol.

What is EN 16931 and why does it matter?

EN 16931 is the EU's structured e-invoice standard. Mandates are rolling out across the EU, starting with Belgium in 2026, so a normal PDF will no longer satisfy many tax authorities. Pay Day produces compliant Factur-X and Peppol BIS 3.0 invoices built to that standard.

Which platforms does Pay Day support?

Pay Day runs on iPhone. No desktop software and no separate bookkeeping suite required.

How do I cancel or get a refund?

Manage or cancel your subscription anytime in your Apple ID settings; it renews automatically unless cancelled at least 24 hours before the period ends. Refunds are handled by Apple through your purchase history.

Be ready for the EU e-invoicing mandates. Start invoicing free today.

Free unlimited invoicing; Pro is a monthly or annual subscription (7-day free trial on the annual plan), and Peppol sends plus optional AI run on one-time credit packs.