Elefthero
01 / 08
OpenAI Codex Hackathon · Apps for your life

The open-source way to invoice in Greece.

A self-hosted invoicing workspace for Greek small businesses—built around AADE myDATA, transparency, and control over the records that matter.

Use arrow keys or the controlsElefthero
Elefthero
02 / 08
The problem

Compliance should not create another dependency.

Greek businesses must transmit invoice data to AADE myDATA. For many small businesses, the alternatives can feel costly, opaque, rigid, or simply not designed around a calm everyday workflow.

FREEDOMRun it yourself

MIT-licensed, self-hosted, and designed to keep the business database under the operator’s control.

OPENNESSSee what happened

Sent and received AADE XML, MARK, UID, QR URL, and activity records are visible for review.

ACCESSIBILITYMake it usable

Greek/English controls, focused workflows, and adjustable visual preferences for everyday work.

Why Elefthero
Elefthero
03 / 08
Focused product

Six supported documents. One understandable workflow.

Elefthero deliberately avoids becoming a broad enterprise ERP. It supports the high-value small-business document flows and handles their AADE rules explicitly.

1.1 · Τιμολόγιο Πώλησης2.1 · Τιμολόγιο Παροχής5.1 · Συσχετιζόμενο Πιστωτικό11.1 · ΑΛΠ11.2 · ΑΠΥ11.4 · Πιστωτικό Λιανικής
SMART CREDIT FLOWCopy the original safely

`5.1` links to transmitted 1.1/2.1 documents and sends the original MARK; retail 11.4 copies lines without forbidden AADE correlation fields.

RETAIL DEFAULTSLess unnecessary typing

Retail receipts use the correct customer defaults and hide saved-client selection where it is not relevant.

VALIDATIONRules before submission

VAT exemption reasons, payment methods, classifications, currency, totals, and XML structure are checked before AADE receives the document.

Supported AADE workflows
Elefthero
04 / 08
From draft to proof

A transparent path from invoice to AADE.

1. CONFIGUREBusiness profile, issuer VAT, series, environment, encrypted credentials.
2. BUILDLines, quantity, VAT, exemption reasons, payment method, and E3 classifications.
3. GENERATECreate schema-aware myDATA XML and retain the exact sent payload.
4. TRANSMITSend to real AADE Test or Production and retain the returned XML.
5. KEEPStore MARK, UID, QR URL, PDF, reports, and reusable templates.
No hidden submission process
Elefthero
05 / 08
Technical implementation

Small, self-hosted, and operational.

A deliberately small architecture separates public access, application logic, local records, and external compliance services.

Browser

Greek/English UI, accessibility preferences, and CSRF-protected state changes.

→
Cloudflare Tunnel

A named tunnel exposes a hostname without opening an inbound application port.

→
Gunicorn + Flask

systemd-managed application, encrypted settings, users, rate limiting, optional TOTP.

→
SQLite + AADE

Local invoice and audit data, HTTPS AADE XML transmission, VIES/ΓΕΜΗ enrichment.

Python · Flask · SQLite · Gunicorn · Cloudflare Tunnel
Elefthero
06 / 08
Trust and safety

Security should be practical, not performative.

  • AADE, Resend, Turnstile, and TOTP secrets are encrypted at rest and never committed to Git.
  • Passwords are hashed; optional authenticator-app 2FA adds a QR-based TOTP challenge.
  • Every POST action requires a server-validated CSRF token.
  • Password, Turnstile, and OTP failures share configurable login rate limiting.
  • Developer logs retain the technical evidence needed to investigate outcomes.
Security + usability
Elefthero
07 / 08
Impact

Give the business owner answers, not another support ticket.

CLIENTSUseful records

VIES validation, optional ΓΕΜΗ enrichment, reusable addresses, filters, analytics, and invoices grouped by type.

DOCUMENTSProfessional proof

Inline PDFs with business identity, VAT breakdown, payment method, MARK, UID, QR link, notes, and optional manual email delivery.

OPERATORSReal ownership

Templates, editable draft reuse, local backups, Test-before-Production workflow, and accountant-friendly inspectability.

The impact is not only a lower software bill. It is the ability to understand what was sent, keep it locally, and discuss it clearly with an accountant.

Built for small businesses, not vendor lock-in
Elefthero
08 / 08
Open source · self-hosted · inspectable

Invoice freely.
Stay responsible.

Elefthero is a working, public, MIT-licensed project with real AADE Test submission. It is not accounting advice; businesses should always review compliance with a qualified accountant.

github.com/achouvardas/Elefthero

Thank youOpenAI Codex Hackathon
Elefthero
OpenAI Codex Hackathon
Apps for your life

The open-source way to invoice in Greece.

Self-hosted AADE myDATA invoicing for Greek small businesses—transparent, accessible, and free from vendor lock-in.

Elefthero · Open source · Self-hosted · Inspectable