> ## Documentation Index
> Fetch the complete documentation index at: https://docs.invopop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Greece FAQ

> Frequently asked questions about invoicing compliance in Greece

### Compliance questions

**Greece**

<AccordionGroup>
  <Accordion title="When does mandatory e-invoicing start in Greece?">
    B2G has been mandatory since 2023 (phased in by company size). B2B reporting through myDATA has been mandatory for all transactions since 2021. Full structured B2B e-invoicing is being phased in following EU ViDA timelines.
  </Accordion>

  <Accordion title="Who can act as a supplier in Greece?">
    Any entity with a Greek AFM (tax ID) registered with the IAPR. Foreign businesses operating in Greece need a Greek fiscal representative or a non-resident AFM.
  </Accordion>

  <Accordion title="What are the legal obligations for receiving invoices in Greece?">
    Recipients must classify each received invoice in myDATA (καταχώρηση) within the deadline matching their books. Standard archival is 5 years.
  </Accordion>

  <Accordion title="What periodic reporting obligations exist in Greece?">
    Monthly or quarterly VAT (Φ2) declarations, plus the annual VAT clearing return (Φ1). Withholding taxes have their own schedule. myDATA classification of issued and received invoices is continuous and feeds the periodic returns.
  </Accordion>
</AccordionGroup>

**myDATA**

<AccordionGroup>
  <Accordion title="What invoice types are available for myDATA?">
    Greece's myDATA system uses a detailed set of invoice type codes that classify every transaction reported to the tax authority (IAPR). Each type has a numeric code (like `1.1` or `11.1`) and describes the nature of the transaction — whether it's a standard sale, a service, a credit note, a retail receipt, and so on.

    When using GOBL, many of these types are assigned automatically based on the invoice type and tags you set. For the rest, you can set the `gr-mydata-invoice-type` extension directly in the tax section of your invoice, using type `other`.

    ### Sales Invoices (1.x)

    | Code  | Description                                                   | GOBL Type  | Tags                    |
    | ----- | ------------------------------------------------------------- | ---------- | ----------------------- |
    | `1.1` | Sales Invoice                                                 | `standard` | `goods`                 |
    | `1.2` | Sales Invoice / Intra-community Supplies                      | `standard` | `goods`, `export`, `eu` |
    | `1.3` | Sales Invoice / Third Country Supplies                        | `standard` | `goods`, `export`       |
    | `1.4` | Sales Invoice / Sale on Behalf of Third Parties               | `standard` | `goods`, `self-billed`  |
    | `1.5` | Sales Invoice / Clearance of Sales on Behalf of Third Parties | `other`    | —                       |
    | `1.6` | Sales Invoice / Supplemental Accounting Source Document       | `other`    | —                       |

    ### Service Invoices (2.x)

    | Code  | Description                                                        | GOBL Type  | Tags                       |
    | ----- | ------------------------------------------------------------------ | ---------- | -------------------------- |
    | `2.1` | Service Rendered Invoice                                           | `standard` | *(default)* or `services`  |
    | `2.2` | Intra-community Service Rendered Invoice                           | `standard` | `services`, `export`, `eu` |
    | `2.3` | Third Country Service Rendered Invoice                             | `standard` | `services`, `export`       |
    | `2.4` | Service Rendered Invoice / Supplemental Accounting Source Document | `other`    | —                          |

    ### Credit Invoices (5.x)

    | Code  | Description                     | GOBL Type     | Tags |
    | ----- | ------------------------------- | ------------- | ---- |
    | `5.1` | Credit Invoice / Associated     | `credit-note` | —    |
    | `5.2` | Credit Invoice / Non-Associated | `other`       | —    |

    ### Retail / Simplified (11.x)

    | Code   | Description                                     | GOBL Type     | Tags                                 |
    | ------ | ----------------------------------------------- | ------------- | ------------------------------------ |
    | `11.1` | Retail Sales Receipt (ΑΛΠ)                      | `standard`    | `goods`, `simplified`                |
    | `11.2` | Service Rendered Receipt (ΑΠΥ)                  | `standard`    | `services`, `simplified`             |
    | `11.3` | Simplified Invoice                              | `standard`    | `simplified`                         |
    | `11.4` | Retail Sales Credit Note                        | `credit-note` | `simplified`                         |
    | `11.5` | Retail Sales Receipt on Behalf of Third Parties | `credit-note` | `goods`, `simplified`, `self-billed` |

    Additional codes exist for proof of expenditure (3.x), self-delivery / self-supply (6.x), contracts and rents (7.x, 8.x, 15.x, 16.x), expense / purchase records (13.x, 14.x), and accounting entries (17.x).
  </Accordion>

  <Accordion title="What if my business already uses another myDATA provider?">
    Greek regulation does not allow two myDATA providers to operate simultaneously for the same VAT number. If your business currently uses a different provider, you will need to switch to Invopop's provider (ILYDA) before issuing invoices through the platform.

    The regulatory restriction applies to simultaneous use of multiple providers, not to changing from one to another. See the [supplier registration](/guides/gr-iapr#register-a-supplier) section in our Greece guide for details on the onboarding process, or contact us via Slack or [support@invopop.com](mailto:support@invopop.com).
  </Accordion>

  <Accordion title="Are there special supplier obligations under myDATA?">
    Each AFM can have only one active myDATA provider at a time — switching providers requires deregistering the previous one in Taxisnet. The supplier must also declare its issuance branch (κλειδί χρήστη) and issuance series (σειρά).
  </Accordion>

  <Accordion title="What are the legal obligations for receiving invoices through myDATA?">
    Recipients must classify (χαρακτηρισμός) every issued invoice that lists them as counterpart, by the periodic return deadline. Failure to classify exposes the recipient to fines and discrepancies in IAPR's automated VAT reconciliation.
  </Accordion>

  <Accordion title="What reporting obligations does myDATA impose?">
    Continuous: every issued invoice transmitted in real time, every received invoice classified. Supplementary monthly/quarterly aggregations (e.g., E3 income statements) reconcile to myDATA totals automatically — discrepancies trigger IAPR queries.
  </Accordion>
</AccordionGroup>

### Invoicing questions

**myDATA**

<AccordionGroup>
  <Accordion title="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.
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="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](https://docs.gobl.org), this type can be set using the `gr-mydata-invoice-type` extension in the tax section and setting the [GOBL invoice type](https://docs.gobl.org/draft-0/bill/invoice) to other.

    Alternatively, GOBL will set the extension for you based on the type and the tax tags you set in your [GOBL invoice](https://docs.gobl.org/draft-0/bill/invoice). You can read more in the [GOBL Greece Tax Regime readme](https://github.com/invopop/gobl/blob/main/regimes/gr/README.md).

    If you produce a PDF version of the invoice, the invoice type label will be displayed instead of "Invoice".
  </Accordion>

  <Accordion title="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](https://github.com/invopop/gobl/blob/main/regimes/gr/README.md).
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="Where do I find Greece-specific GOBL documentation?">
    See the [Greece tax regime in GOBL](https://docs.gobl.org/regimes/gr) for tax categories and AFM rules. The myDATA mapping lives in [`gr-mydata-v1`](https://docs.gobl.org/addons/gr-mydata-v1) including all invoice type codes.
  </Accordion>
</AccordionGroup>

### Registering supplier questions

**myDATA**

<AccordionGroup>
  <Accordion title="How do I register a supplier with myDATA?">
    Production registration is multi-step: authorize ILYDA in Taxisnet, declare ILYDA as issuer in myDATA, sign the service agreement, then onboard with Invopop. Sandbox uses a shared pre-registered AFM, no manual steps required.
  </Accordion>

  <Accordion title="How do I onboard a new supplier with ILYDA?">
    Contact Invopop to begin the onboarding flow with ILYDA. The supplier authorizes ILYDA in Taxisnet, declares ILYDA as their issuer in myDATA, and signs ILYDA's service agreement. Sandbox uses a shared test AFM (`177472438`).
  </Accordion>

  <Accordion title="What credentials does myDATA require to authenticate a supplier?">
    No supplier-side certificates. ILYDA submits to myDATA on the supplier's behalf using its provider credentials, authorized by the supplier through Taxisnet. The supplier holds only their Taxisnet username/password.
  </Accordion>

  <Accordion title="How are supplier credentials stored in Invopop for Greece?">
    Suppliers don't upload credentials to Invopop — ILYDA holds the IAPR submission credentials on the supplier's behalf based on the Taxisnet authorization. Only the AFM and registration metadata are stored in Invopop.
  </Accordion>
</AccordionGroup>

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