Peppol Invoicing for Greek Sellers

If you are a Greek seller, there are some additional requirements you need to be aware of when creating invoices using the Oxygen PEPPOL API.

Invoice number BT-1

Greek sellers must follow a specific format for the invoice number when issuing invoices. The invoice_number must consist of the following components, separated by the | character:

Part	Description
seller_tin	Seller's VAT number (nine digits – without the "EL" prefix)
issue_date	Issue date in "DD/MM/YYYY" format
branch_code	Issuer branch code (use value "0" for the main branch)
invoice_type	myDATA invoice type code
series	Document series (use value "0" if not applicable)
number	Sequential number

Invoice number format

{seller_tin}|{issue_date}|{branch_code}|{invoice_type}|{series}|{number}

For example, an invoice for type 1.1, with no document series, and sequential number 14, that was issued on 14/01/2026 by a seller with TIN 888888888 from the branch 6, would have the following invoice number: 888888888|14/01/2026|6|1.1|ΤΔΑ|14.

myDATA invoice types

Below are the supported myDATA invoice type codes when issuing invoices as a Greek seller:

Invoice Type Code	Description
1.1	Standard invoice (Τιμολόγιο Πώλησης)
1.6	Supplementary Standard Invoice (Συμπληρωματικό Τιμολόγιο Πώλησης)
2.1	Service invoice (Τιμολόγιο Παροχής)
2.4	Supplementary Service Invoice (Τιμολόγιο Παροχής)
5.1	Correlated Credit Note (Συσχετιζόμενο Πιστωτικό Τιμολόγιο)
5.2	Credit Note (Πιστωτικό Τιμολόγιο)

Buyer reference BT-10

The BT-10 field is an identifier assigned by the Buyer for internal routing purposes. This is an INFORMATIONAL ROUTING FIELD that identifies the Contracting Authority (Αναθέτουσα Αρχή - Α.Α) responsible for managing the B2G invoice.

BT-10 is the only field in the format that institutionally identifies the Contracting Authority by name. It may also optionally include an internal administrative unit within the Contracting Authority.

Format

The BT-10 field can take one of the following formats:

When Buyer BT-44 and Contracting Authority differ:

• {Contracting Authority Description}
• {Contracting Authority Description}|{Internal Unit Description}
• {Contracting Authority Description}|{Internal Unit Code}

When Buyer BT-44 and Contracting Authority are the same:

• BT-10 may be omitted (not mandatory)
• {Internal Unit Description/Code}
• {Internal Unit Description}|{Internal Unit Code}

Examples

• ΥΠΟΥΡΓΕΙΟ ΠΕΡΙΒΑΛΛΟΝΤΟΣ ΚΑΙ ΕΝΕΡΓΕΙΑΣ ΥΠΕΝ
• ΔΟΥ ΙΩΑΝΝΙΝΩΝ
• Νοσοκ ΕΥΑΓΓΕΛΙΣΜΟΣ|ΦΑΡΜΑΚΕΙΟ
• Νοσοκ ΕΥΑΓΓΕΛΙΣΜΟΣ|ΔΙΑΧΕΙΡΙΣΗ ΤΡΟΦΙΜΩΝ
• ΥΠΟΥΡΓΕΙΟ ΜΕΤΑΝΑΣΤΕΥΣΗΣ ΚΑΙ ΑΣΥΛΟΥ|ΤΕΧΝΙΚΗ ΥΠΗΡΕΣΙΑ
• VII ΜΟΝΑΔΑ ΣΤΡΑΤΟΥ|Στρατιωτικό Πρατήριο Αλεξανδρούπολης
• Παν/μιο ΑΙΓΑΙΟΥ|ΣΧΟΛΗ ΘΕΤΙΚΩΝ ΕΠΙΣΤΗΜΩΝ στη ΣΑΜΟ
• Νοσοκ ΕΥΑΓΓΕΛΙΣΜΟΣ|XYZ123ABC

WARNING

No spaces should exist immediately before or after the | separator. The Contracting Authority can use the "SOFT REJECT" action if BT-10 is incorrect, allowing the issuer to reissue the invoice with the correct BT-10 value.

Project reference BT-11

The BT-11 field identifies the goods/service/study/project reference to which the invoice refers. This is a ROUTING FIELD used as a Contract Identifier to determine the budget type and route the electronic invoice to the appropriate information system for receipt, settlement, and payment of the related expense.

Format and values

The BT-11 field takes one of the following values based on the budget type:

Budget Type	Format	Description	Routing Destination	Applies To
1	1|{ΑΔΑ}	Regular Budget (Τακτικός Προϋπολογισμός) ΑΔΑ = Internet Posting Number of the Commitment Decision	ΟΠΣΔΠ system	Central Government entities (Article 14, Law 4270/2014)
2	2|{Ενάριθμος}	Public Investment Budget (ΠΔΕ) Ενάριθμος = 14-digit PDE project code	e-ΠΔΕ system	All General Government entities (Central Government and Other General Government)
3	3|{ΑΔΑ}	Other Budgets (Λοιποί Προϋπολογισμοί) ΑΔΑ = Internet Posting Number of the Commitment Decision	Entity ERPs	Other General Government entities (e.g., Municipalities, NPDD) - NOT Central Government entities

Examples

• Regular Budget (Type 1):1|ΨΥΛΑΩ5ΧΓ — Ministry of Justice

• Public Investment Budget (Type 2):2|2023ΤΑ07500012 — Ministry of Environment and Energy

• Other Budgets (Type 3):3|9Δ134690ΩΣ-ΙΗΙ — Hippokration General Hospital

ΑΔΑ (Internet Posting Number) is the unique code assigned to the Commitment Assumption Decision (ΑΑΥ - Απόφαση Ανάληψης Υποχρέωσης) when posted in the DIAVGEIA system. The ΑΔΑ is referenced in the Contract document as a funding source.

Ενάριθμος is a 14-digit unique identification code for PDE projects, generated by the e-ΠΔΕ system. Format: YYYY (year of first inclusion) + ΣΑ code (Collective Decision code) + sequential number. The Ενάριθμος is always mentioned in the contract.

Credit Notes and BT-11

For credit notes, BT-11 may not exist in all cases. If the credit note relates to a previous debit invoice with the same contract, the BT-11 from the related debit invoice (referenced via BT-25) is used for routing.

WARNING

Only one Project Reference element is allowed per B2G invoice. The contracting authority can use the "SOFT REJECT" action if BT-11 is incorrect or unsuitable, allowing the issuer to reissue the invoice with the correct BT-11 value.

Contract reference BT-12

The BT-12 field is a ROUTING FIELD that contains the contract identification. It is filled with the Contract Internet Posting Number (ΑΔΑΜ - Αριθμός Διαδικτυακής Ανάρτησης Μητρώου) from the Central Electronic Registry of Public Contracts (ΚΗΜΔΗΣ), according to Article 38 of Law 4412/2016.

Format

Scenario	Value	Description
Contract exists in ΚΗΜΔΗΣ	{ΑΔΑΜ}	The ΑΔΑΜ contract number
No written contract (purchases < €2,500)	0|{ΑΔΑ}	Zero, pipe separator, and ΑΔΑ of Commitment Decision (same ΑΔΑ as in BT-11)
ΑΔΑΜ unknown or not applicable	0	Zero
Credit Notes (correlated)	0	Zero (receiving systems will obtain ΑΔΑΜ from the related debit invoice via BT-25)

Examples

• 24PROC012345678 — Contract ΑΔΑΜ from ΚΗΜΔΗΣ
• 0|ΨΥΛΑΩ5ΧΓ — No written contract, supplies under €2,500
• 0 — ΑΔΑΜ unknown or credit note

INFO

ΑΔΑΜ is the unique number assigned to a Contract document when posted in ΚΗΜΔΗΣ. Search for contracts at: http://www.eprocurement.gov.gr/kimds2/unprotected/searchRequests.htm

The Contracting Authority can use the "SOFT REJECT" action if BT-12 is incorrect, allowing the issuer to reissue the invoice with the correct BT-12 value.

Purchase order reference BT-13

The BT-13 field is a ROUTING FIELD that contains the purchase order identification. It is an identifier for a purchase order referenced at invoice level, issued by the Buyer.

INFO

The Contracting Authority can use the "SOFT REJECT" action if BT-13 is incorrect, allowing the issuer to reissue the invoice with the correct BT-13 value.

Despatch advice reference BT-16

The BT-16 field contains the identification number of the Despatch Advice (ΔΑ - Δελτίο Αποστολής) for the goods to which the invoice refers. According to PEPPOL, the correspondence between invoice and despatch advice is 1-to-1.

INFO

If the invoice is cumulative and corresponds to more than one Despatch Advice (all referring to the same ΑΔΑ), for Greek suppliers to the Greek Public Sector based in Greece, BT-16 should contain the identifier of the first Despatch Advice and the remaining Despatch Advices should be listed in group BG-24.

Buyer name BT-44

The BT-44 field is a ROUTING FIELD that contains the full name of the Buyer. For the Greek Public Sector, this is the parent administrative structure/entity (e.g., Independent Authority for Public Revenue - ΑΑΔΕ, Ministry of Digital Governance, Evangelismos Hospital, Ministry of National Defense, Ministry of Citizen Protection) or generally any entity of the Greek State under Article 14 of Law 4270/2014, or any legal entity executing a public contract that carries out the expenditure. The Buyer is always the holder of the VAT number.

Two scenarios

1. Buyer is a parent entity with subordinate Contracting Authorities:

• The Buyer is a parent state structure with a VAT number that may have one or more subordinate Contracting Authorities (Α.Α) without their own VAT numbers
• The Contracting Authority (referenced in BT-10 and BT-46) carries out the expenditure and pays the invoice, inheriting the Buyer's VAT number from BT-44

2. Buyer is the Contracting Authority itself:

• The Buyer is a Contracting Authority (e.g., University of the Aegean, Evangelismos Hospital) that has its own VAT number
• In this case, BT-10 and BT-44 have identical values, and BT-10 (being optional) may be omitted from the invoice XML unless it carries supplementary useful information (see BT-10 description)

INFO

The Buyer is always the VAT number holder. If the Contracting Authority does not have its own VAT number, it inherits the VAT number from the Buyer (BT-44) to which it is subordinate.

Buyer identifier BT-46

The BT-46 field is a ROUTING FIELD that contains the Contracting Authority (Αναθέτουσα Αρχή - Α.Α) code/identifier. For the Greek Public Sector, this is the legally designated Contracting Authority that receives and manages the invoice, as defined in the "REGISTRY OF CONTRACTING AUTHORITIES" (ΜΗΤΡΩΟ ΑΝΑΘΕΤΟΥΣΩΝ ΑΡΧΩΝ) for electronic invoicing by ΓΓΠΣ ΨΔ, with the field "ΚΩΔΙΚΟΣ ΑΝΑΘΕΤΟΥΣΑΣ" (e.g., 2048.8010430600.00061) available at www.gsis.gr/e-Invoice.

BT-46 refers to an autonomous administrative structure/unit (e.g., Ministry of Digital Governance, Tax Office of Ioannina, University of the Aegean, Evangelismos Hospital) of the Buyer (as described in BT-44). This unit is subordinate to the Buyer (BT-44) or can be the Buyer itself, with its own (or inherited) VAT number.

Relationship with other fields

• BT-46 ↔ BT-10: 1-to-1 correspondence. Both refer to the same autonomous administrative entity. BT-46 provides the code (e.g., 1020.E00321.0001), while BT-10 provides the descriptive name.
• BT-44: Buyer description (e.g., "ΕΛΚΕ Πανεπιστημίου Κρήτης")
• BT-48: Buyer's VAT number

Examples

• If the Contracting Authority has its own VAT number, it is also the Buyer BT-44
• If the Contracting Authority does not have its own VAT number, the Buyer BT-44 is the parent entity from which the Contracting Authority inherits the VAT number (e.g., MINISTRY OF CITIZEN PROTECTION for a Police Department)

INFO

The Contracting Authority can use the "SOFT REJECT" action if BT-46 is incorrect, allowing the issuer to reissue the invoice with the correct BT-46 value.

Buyer VAT identifier BT-48

The BT-48 field is a ROUTING FIELD that contains the Buyer's VAT number (ΑΦΜ - Αριθμός Φορολογικού Μητρώου), also known as the Buyer's VAT identification number. This is the VAT number of the Buyer as described in field BT-44, with the country prefix according to EN ISO 3166-1.

Format

For Buyers based in Greece, the country prefix is EL (Latin characters).

Example: EL997001671 for the Ministry of Digital Governance (Υ.ΨΗ.Δ)

INFO

If the Contracting Authority (Α.Α) does not have its own VAT number, it inherits the VAT number from the parent administrative entity (e.g., ΑΑΔΕ, Ministry of Digital Governance) to which it is subordinate.