myDATA MARK
Generator
Generate correctly formatted Greek myDATA MARK and UID pairs for software development and QA testing — entirely in your browser.
About Greek myDATA MARK (Electronic Invoicing Protocol)
MARK (Monadikos Arithmos Registration Kataxorisis) is the official electronic ledger protocol number assigned by the Independent Authority for Public Revenue (AADE / IAPR) of Greece for each invoice transmitted to the myDATA platform (Ministerial Decision A.1138/2020).
The UID (Unique Identification Number, a 40-character hexadecimal SHA-1 hash) identifies the transaction uniquely and pairs with the 14–16 digit numeric MARK for full audit traceability.
myDATA Issuance and Transmission Flow
| Step | Description |
|---|---|
| 1. Hash the invoice | The issuer's ERP generates the XML invoice payload and calculates its 40-hex SHA-1 cryptographic hash (UID). |
| 2. Submit to AADE | The document is submitted via REST API to AADE's myDATA platform endpoint. |
| 3. AADE validates and assigns MARK | AADE validates the XML schema, verifies the supplier AFM, and returns the sequential MARK ledger number. |
| 4. Book MARK and UID | Both supplier and customer book the MARK and UID into their digital VAT books for tax deduction. |
Frequently Asked Questions & Technical Guidelines
Why is UID and MARK pairing important for developers and QA engineers?
ERP and invoicing software must correctly generate and store both the UID (the invoice's own SHA-1 hash) and the MARK (the ledger number AADE returns) together — losing or mismatching either one breaks the audit trail required for VAT deduction and compliance checks. Testing against correctly paired, correctly formatted sample values helps catch integration bugs before they hit production invoices.
Are the generated numbers official or real?
No. These are synthetic test values with the correct format — they are not issued by AADE, do not correspond to any real invoice or transaction, and must never be submitted to the myDATA platform or used on real invoices.