myDATA & IAPR Guide

Send invoices and credit notes to the Greek IAPR via the myDATA platform.

Introduction

The myDATA (My Digital Accounting and Tax Application) platform is Greece’s standardized electronic invoicing and bookkeeping system, managed by the Independent Authority for Public Revenue (IAPR). This system enables businesses to report invoices and accounting data in real time, ensuring compliance with Greek tax regulations.

This guide will walk you through the process of reporting invoices to the IAPR using myDATA, first registering a supplier, and then issuing invoices and credit notes in their name.

-	Sandbox	Live
Supplier	Must use test supplier with tax ID 177472438	Real supplier registration required
Environment	myDATA test	myDATA production

Prerequisites

To issue invoices in Greece, you will need:

• Supplier details, including company name, TIN, and address.
• Customer details for B2B transactions, including name, TIN or international ID, and address.
• Line and item details, including quantity, price, description, applicable VAT rates, and, optionally, income classification codes.
• To have chosen an invoice series.

Setup

To issue invoices, follow these instructions in the Invopop Console:

1. Connect ILYDA Greece App

   1. Navigate to Configuration → Apps.
   2. Find ILYDA Greece in the app discovery list.
   3. Click Connect to activate.

   

   The ILYDA Greece app will send your invoices to the appropriate environment based on whether your current workspace is Sandbox or Live.

2. Prepare Invoice Workflow

   Template

   IAPR Invoice Workflow

   This workflow will issue an invoice through IAPR.

   Add to my workspace

   Code

   Copy and paste into a new Empty Invoice workflow code view.

   Example IAPR invoice workflow

   {
     "name": "Issue IAPR Invoice",
     "description": "Send GOBL invoices to the Greek IAPR via ILYDA eInvoicing.",
     "schema": "bill/invoice",
     "steps": [
       {
         "id": "883baa10-abd5-11ef-8b96-dd5de8906f90",
         "name": "Set Silo Entry State",
         "config": {
           "state": "processing"
         },
         "summary": "Set state to `processing`{.state .processing}",
         "provider": "silo.state"
       },
       {
         "id": "e9fad100-abd4-11ef-8b96-dd5de8906f90",
         "name": "Add Sequential Code",
         "config": {
           "name": "IAPR Invoices",
           "start": 1,
           "padding": 3
         },
         "summary": "Dynamic · IAPR Invoices · 1",
         "provider": "sequence.enumerate"
       },
       {
         "id": "fc75e4f0-8721-11ef-a962-73e3f2037a52",
         "name": "Sign Envelope",
         "provider": "silo.close"
       },
       {
         "id": "649aca50-9064-11ef-8f9e-39835766d0bc",
         "name": "Send to IAPR (via ILYDA)",
         "provider": "ilyda.send"
       },
       {
         "id": "6f77ad10-a32b-11ef-9707-79bbd71238cd",
         "name": "Set State",
         "config": {
           "state": "sent"
         },
         "summary": "Set state to `sent`{.state .sent}",
         "provider": "silo.state"
       }
     ],
     "rescue": [
       {
         "id": "e8c9c0a0-a32a-11ef-9707-79bbd71238cd",
         "name": "Set State",
         "config": {
           "state": "error"
         },
         "summary": "Set state to `error`{.state .error}",
         "provider": "silo.state"
       }
     ]
   }
   

   Build from scratch

   First, review our workflows guide to understand the basics.

   In Console create a new workflow and select Empty Invoice workflow in the template selector, then add the following steps:

   1. Set State - to Processing.
   2. Add Sequential Code - with dynamic sequences and a name like “IAPR Invoices”.
   3. Sign Envelope: The envelope must be signed before processing.
   4. Send to IAPR (via ILYDA).
   5. Set State - to Sent.

   Finally, in the Error Handling area, add the Set State action and select Error.

   Add any additional steps you may need, and save the new workflow.

Running

In this section, we’ll provide details on how to register new suppliers and issue invoices on their behalf.

Register a supplier

Supplier registration is only possible in production. In the sandbox environment, your invoices must use a supplier with the tax ID code set to 177472438 which is the TIN of the test supplier pre-enabled in that environment.

Invopop has partnered with ILYDA to issue invoices in Greece. Each supplier must be registered with ILYDA before they can issue invoices. The registration process involves providing your company details, authorizing ILYDA as your electronic invoicing provider in TAXIS, and signing a service agreement.

Greek regulation does not allow two myDATA providers to operate simultaneously for the same VAT number. If a supplier currently uses a different provider, they must switch to ILYDA before issuing invoices through Invopop. Switching providers is allowed; the restriction only applies to simultaneous use. See the Greece FAQ for more details.

All communication with ILYDA must go through Invopop. Neither you nor the supplier should contact ILYDA directly at any point during or after the onboarding process. Direct contact can lead to confusion, billing issues, and delays. Always send any questions, documents, or requests to [e-mail].

1. Supplier authorizes ILYDA as their e-invoicing provider

   The supplier must authorize ILYDA as their e-invoicing provider in TAXIS:

   1. Go to myTaxisnet and log in with the company’s credentials.
   2. Select the Authorizations (“Εξουσιοδοτήσεις”) tab on the left sidebar.
   3. Scroll down to the Providers of E-invoicing (“Πάροχοι Ηλεκτρονικής Τιμολόγησης”) section.
   4. Click New (“Νέα”).
   5. Enter ILYDA’s VAT number: 094359854 and submit the authorization.

   Take note of the date the authorization was submitted — you will need it in the next step.

2. Send the supplier's details to Invopop

   Contact [e-mail] with the following information about the supplier you want to register:

   • Company name
   • Business activity
   • VAT number (ΑΦΜ)
   • Tax office (ΔΟΥ)
   • Full address
   • Phone number
   • Email address
   • Legal representative name
   • TAXIS authorization date (from step 1)

   Also specify which document types the supplier needs to issue:

   • B2B: invoices issued to private sector businesses.
   • B2G: invoices issued to public sector entities.
   • B2C: documents issued for individual retail sales.

   If the supplier issues B2C retail sales documents, Greek regulation requires them to have a backup internet service provider (ISP) to ensure uninterrupted connectivity with the e-invoicing platform. You must also provide:

   • ISP provider name
   • Contract number
   • Contract date
3. Sign the service agreement

   Invopop will prepare a pre-filled service provision contract with ILYDA based on the details provided in step 2. We can send the contract directly to the supplier or to you as the integrator — let us know your preference. The supplier will have to review the contract, sign it, and return the signed copy to us.

4. Confirm and go live

   Once Invopop receives the signed contract, we will complete the onboarding as soon as possible and notify you when the supplier is active and ready to issue invoices.

Send an invoice

The following examples are of partial GOBL documents you can copy and paste directly into the Invopop Console or store via the API as silo entries. Then, you must run the “Issue IAPR Invoice” workflow created during setup.

As usual, the recommended approach for running jobs is to perform two steps; first, upload the document to the silo, second create a job.

GOBL Invoices sent to myDATA require the following properties to perform the correct normalization and validation steps. Invopop will try to assign these automatically, but we recommend defining them explicitly before uploading:

• $region to be set to EL
• $addons to include gr-mydata-v1

Example service invoice (B2B)

In this example, we’re issuing a simple services invoice from a Greek supplier to another Greek business customer.

Notice:

• we’ve added the gr-mydata-v1 addon; this ensures the document will be validated and normalized using the myDATA v1 rules built into the GOBL library,
• we’ve set the services tag; this makes the addon set the gr-mydata-invoice-type extension automatically to 2.1 (service invoice),
• similarly, the credit-transfer payment method will cause the addon to set the gr-mydata-payment-means extension to 1 (credit transfer),
• we added a charge for a special fee (tourist accomodation fee), using the gr-mydata-fee extension,
• the specific income category and type are set using the gr-mydata-income-cat extension and the gr-mydata-income-type extension respectively,
• only VAT rates (standard) have been specified; percentages and values for the gr-mydata-vat-rate extension will be set automatically, and,
• there are no totals or calculations; all these will be made automatically when uploading.

B2B Services Invoice

{
  "$schema": "https://gobl.org/draft-0/bill/invoice",
  "$addons": [
    "gr-mydata-v1"
  ],
  "$tags": [
    "services",
    "simplified"
  ],
  "series": "XXGR",
  "supplier": {
    "name": "Αθηναϊκό Ξενοδοχείο Α.Ε.",
    "tax_id": {
      "country": "EL",
      "code": "177472438"
    },
    "addresses": [
      {
        "num": "28",
        "street": "Λεωφόρος Συγγρού",
        "locality": "Αθήνα",
        "code": "11743",
        "country": "GR"
      }
    ],
    "emails": [
      {
        "addr": "[e-mail]"
      }
    ]
  },
  "customer": {
    "name": "Τεχνολογικές Λύσεις Ελλάς Α.Ε.",
    "tax_id": {
      "country": "EL",
      "code": "841442160"
    },
    "addresses": [
      {
        "num": "15",
        "street": "Οδός Πανεπιστημίου",
        "locality": "Αθήνα",
        "code": "10671",
        "country": "GR"
      }
    ],
    "emails": [
      {
        "addr": "[e-mail]"
      }
    ]
  },
  "lines": [
    {
      "quantity": "3",
      "item": {
        "name": "Διαμονή Deluxe Δίκλινο Δωμάτιο",
        "price": "180.00",
        "unit": "day",
        "ext": {
          "gr-mydata-income-cat": "category1_3",
          "gr-mydata-income-type": "E3_561_001"
        }
      },
      "discounts": [
        {
          "reason": "Εταιρική Έκπτωση",
          "percent": "10%"
        }
      ],
      "taxes": [
        {
          "cat": "VAT",
          "rate": "general"
        }
      ]
    }
  ],
  "charges": [
    {
      "reason": "Τέλος διαμονής παρεπιδημούντων",
      "amount": "21.00",
      "ext": {
        "gr-mydata-fee": "18"
      }
    }
  ],
  "payment": {
    "instructions": {
      "key": "credit-transfer"
    }
  }
}

Example retail sales receipt (B2C)

In this example, we’re issuing a simple goods invoice from a Greek supplier to a Greek final consumer.

Notice:

• we’ve set the goods and the simplified tags; this makes the addon set the gr-mydata-invoice-type extension automatically to 11.1 (retail sales receipt),
• similarly, the cash payment method will cause the addon to set the gr-mydata-payment-means extension to 3 (cash),
• the specific income category and type are set using the gr-mydata-income-cat extension and the gr-mydata-income-type extension respectively,
• only VAT rates (standard) or keys (exempt) have been specified; percentages and values for the gr-mydata-vat-rate extension will be set automatically
• the exemption cause is set using the gr-mydata-exemption extension, and,
• there are no totals or calculations; all these will be made automatically when uploading.

B2C Goods Invoice

{
  "$schema": "https://gobl.org/draft-0/bill/invoice",
  "$addons": [
    "gr-mydata-v1"
  ],
  "$tags": [
    "goods",
    "simplified"
  ],
  "series": "XXGR",
  "supplier": {
    "name": "Ελληνικά Τρόφιμα Α.Ε.",
    "tax_id": {
      "country": "EL",
      "code": "177472438"
    },
    "addresses": [
      {
        "num": "12",
        "street": "Λεωφόρος Βουλιαγμένης",
        "locality": "Αθήνα",
        "code": "11636",
        "country": "GR"
      }
    ],
    "emails": [
      {
        "addr": "[e-mail]"
      }
    ]
  },
  "lines": [
    {
      "quantity": "50",
      "item": {
        "name": "Ελαιόλαδο Extra Virgin 1L",
        "price": "12.50",
        "unit": "unit",
        "ext": {
          "gr-mydata-income-cat": "category1_1",
          "gr-mydata-income-type": "E3_561_001"
        }
      },
      "discounts": [
        {
          "reason": "Έκπτωση Όγκου",
          "percent": "10%"
        }
      ],
      "taxes": [
        {
          "cat": "VAT",
          "rate": "reduced"
        }
      ]
    },
    {
      "quantity": "1",
      "item": {
        "name": "Βιβλία Μαγειρικής",
        "price": "15.00",
        "ext": {
          "gr-mydata-income-cat": "category1_1",
          "gr-mydata-income-type": "E3_561_001"
        }
      },
      "taxes": [
        {
          "cat": "VAT",
          "key": "exempt",
          "ext": {
            "gr-mydata-exemption": "3"
          }
        }
      ]
    }
  ],
  "payment": {
    "instructions": {
      "key": "cash"
    }
  }
}

Example accommodation + climate fee invoice (B2C)

In this example, we’re issuing a retail sales receipt for a hotel stay (accommodation taxed at the reduced VAT rate) together with the climate crisis resilience fee on the same document.

Notice:

• we’ve set the services and simplified tags; the addon sets gr-mydata-invoice-type to 11.2 (services receipt), appropriate for B2C,
• the accommodation line uses the reduced VAT rate (13%); the gr-mydata-vat-rate extension is filled in on build,
• the climate crisis resilience fee is added as a charge with gr-mydata-other-tax set to 22 (hotels 4 stars, 7.00€ per room/night) and gr-mydata-tax-type 3 (other tax), as in the built version,
• the card payment method maps to gr-mydata-payment-means 7 (card payment), and,
• there are no totals in the minimal example; amounts are calculated when the document is built or uploaded.

B2C Accommodation + Climate Fee

{
  "$schema": "https://gobl.org/draft-0/bill/invoice",
  "$regime": "EL",
  "$addons": [
    "gr-mydata-v1"
  ],
  "$tags": [
    "services",
    "simplified"
  ],
  "series": "Plato",
  "code": "216",
  "supplier": {
    "name": "Cyberdyne Συστήματα Α.Ε.",
    "tax_id": {
      "country": "EL",
      "code": "177472438"
    },
    "addresses": [
      {
        "num": "28",
        "street": "Λεωφόρος Συγγρού",
        "locality": "Αθήνα",
        "code": "11743",
        "country": "GR"
      }
    ],
    "emails": [
      {
        "addr": "[e-mail]"
      }
    ]
  },
  "lines": [
    {
      "quantity": "2",
      "item": {
        "name": "Hotel room (2 nights)",
        "price": "120.00"
      },
      "taxes": [
        {
          "cat": "VAT",
          "rate": "reduced"
        }
      ]
    }
  ],
  "charges": [
    {
      "reason": "Climate Crisis Resilience Fee (2 nights x 7.00€)",
      "amount": "14.00",
      "ext": {
        "gr-mydata-other-tax": "22"
      }
    }
  ],
  "payment": {
    "instructions": {
      "key": "card"
    }
  }
}

Example climate fee standalone invoice (B2B)

In this example, we’re issuing a standalone climate fee invoice (no lines) from a Greek supplier to another Greek business customer. This is an example of how special records and other document types can be used in Greece.

Notice:

• we’ve set the other type and the 8.2 invoice type (climate crisis fee collection) explicitly using the gr-mydata-invoice-type extension,
• the climate fee is set as a charge using the gr-mydata-other-tax extension set to 8 (climate crisis fee),
• there are no lines as this special record type doesn’t allow them,
• the credit-transfer payment method will cause the addon to set the gr-mydata-payment-means extension to 1 (credit transfer), and,
• there are no totals or calculations; all these will be made automatically when uploading.

B2B Climate Fee Invoice

{
  "$schema": "https://gobl.org/draft-0/bill/invoice",
  "$addons": [
    "gr-mydata-v1"
  ],
  "type": "other",
  "series": "XXGR",
  "tax": {
    "ext": {
      "gr-mydata-invoice-type": "8.2"
    }
  },
  "supplier": {
    "name": "Αθηναϊκό Ξενοδοχείο Α.Ε.",
    "tax_id": {
      "country": "EL",
      "code": "177472438"
    },
    "addresses": [
      {
        "num": "28",
        "street": "Λεωφόρος Συγγρού",
        "locality": "Αθήνα",
        "code": "11743",
        "country": "GR"
      }
    ],
    "emails": [
      {
        "addr": "[e-mail]"
      }
    ]
  },
  "customer": {
    "name": "Τεχνολογικές Λύσεις Ελλάς Α.Ε.",
    "tax_id": {
      "country": "EL",
      "code": "841442160"
    },
    "addresses": [
      {
        "num": "15",
        "street": "Οδός Πανεπιστημίου",
        "locality": "Αθήνα",
        "code": "10671",
        "country": "GR"
      }
    ],
    "emails": [
      {
        "addr": "[e-mail]"
      }
    ]
  },
  "charges": [
    {
      "reason": "Τέλος ανθεκτικότητας στην κλιματική κρίση",
      "amount": "3.00",
      "ext": {
        "gr-mydata-other-tax": "8"
      }
    }
  ],
  "payment": {
    "instructions": {
      "key": "credit-transfer"
    }
  }
}

FAQ

What's the workflow for issuing myDATA invoices?

Build a GOBL invoice with the gr-mydata-v1 addon, run the IAPR Issue Invoice workflow. Invopop signs and transmits via ILYDA, retrieves the MARK identifier, and stores it on the silo entry.

How do I configure my workspace for Greek invoicing?

Install the ILYDA Greece app, register the supplier (one provider at a time per VAT — see our FAQ), and run invoices through the IAPR workflow. PDFs are generated alongside the myDATA submission.

How are Greek invoice types specified?

The Greek tax authority (IAPR) requires the invoice type to be specified as part of the invoice. In GOBL, this type can be set using the gr-mydata-invoice-type extension in the tax section and setting the GOBL invoice type to other.

Alternatively, GOBL will set the extension for you based on the type and the tax tags you set in your GOBL invoice. You can read more in the GOBL Greece Tax Regime readme.

If you produce a PDF version of the invoice, the invoice type label will be displayed instead of “Invoice”.

Where can I find the mapping of GOBL fields to myDATA?

For further details on how GOBL prepares data for conversion, see the Greek Tax Regime.

Why is my credit note being rejected with 'Invoice not found' error?

If you issue a credit note shortly after the invoice it refers to, the MyDATA system may reject it because the original invoice hasn’t completed synchronization. You’ll typically see an error like:

Fatal error 301: Invoice with ΜΑΡΚ xxxx not found for VAT number xxxx

This happens because there can be a delay between when an invoice is accepted by MyDATA and when it becomes fully available for reference by other documents like credit notes. This delay can range from a few minutes to several hours, depending on MyDATA system load.

Solution: If you receive this error, retry issuing the credit note after waiting some time. You may need to wait anywhere from a few minutes to several hours for the original invoice to be fully synchronized in the MyDATA system before the credit note can successfully reference it.

Where do I find Greece-specific GOBL documentation?

See the Greece tax regime in GOBL for tax categories and AFM rules. The myDATA mapping lives in gr-mydata-v1 including all invoice type codes.

More available in our Greece FAQ section

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