Step 2 – Issue an invoice · Flexy Provider API

In this step you issue a real document in the test environment: a Sales Invoice (1.1) of €12.40, paid in cash. Every value is ready. You only fill in the issuer's VAT number.

1. Prepare the request body

Save the following as invoice.json:

{
  "document": {
    "provider": "flexy",
    "document_type": "invoice",
    "series": "A",
    "aa": "YYYYMMDDHHMMSS",
    "date": "YYYY-MM-DD",
    "provider_details": {
      "document_type": "1.1",
      "payment_method_type": 3
    },
    "issuer": {
      "legal_name": "Δοκιμαστικός Εκδότης",
      "legal_number": "<VAT NUMBER>",
      "address": {
        "address_line": "Πανεπιστημίου 123",
        "city": "Αθήνα",
        "zip": "10678",
        "country": "GR"
      }
    },
    "counterpart": {
      "legal_name": "Δοκιμαστικός Πελάτης",
      "legal_number": "801434350",
      "address": {
        "address_line": "Σταδίου 456",
        "city": "Θεσσαλονίκη",
        "zip": "54625",
        "country": "GR"
      }
    },
    "items": [
      {
        "title": "Προϊόν δοκιμής",
        "description": "Γραμμή δοκιμής",
        "quantity": "1",
        "unit_measure": "ΤΕΜ",
        "unit_value": "10.00",
        "unit_total": "10.00",
        "taxes": [
          {
            "title": "ΦΠΑ 24%",
            "value_type": "percentage",
            "value": "24.00",
            "tax_sign": "+",
            "on_vat": true,
            "provider_details": { "provider_code": "1" }
          }
        ],
        "provider_details": {
          "classification_category": "category1_1",
          "classification_type": "E3_561_001",
          "vat_classification_category": "1"
        }
      }
    ],
    "totals": {
      "line_extension_amount": "10.00",
      "tax_exclusive_amount": "10.00",
      "tax_amount": "2.40",
      "tax_inclusive_amount": "12.40",
      "payable_amount": "12.40"
    },
    "tax_breakdown": [
      {
        "tax_category_id": "S",
        "tax_rate_percent": "24.00",
        "taxable_amount": "10.00",
        "tax_amount": "2.40"
      }
    ]
  }
}

You only fill in the issuer's VAT number. The page fills in date and aa every time you open it:

Field	Value
`issuer.legal_number`	You: replace `<VAT NUMBER>` with the VAT number (ΑΦΜ) of the business issuing the invoice (9 digits).
`date`	The page: today's date (Greek time), in `YYYY-MM-DD` format.
`aa`	The page: the current date and time down to the second, e.g. `20261004153012` for 4 Oct 2026 15:30:12. Every submission gets a new sequence number this way; for a new submission, reload the page.

2. Send it

curl https://provider-staging.flexy.gr/api/v1/documents/ \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  --data-binary @invoice.json

3. The response

Once AADE registers the document, the API answers with HTTP 201:

{
  "document": {
    "document_type": "invoice",
    "aa": "20261004102731",
    "series": "A",
    "issue_date": "2026-10-04",
    "id": "969950c9-2bfa-48c8-ba15-ebe12d02b743",
    "provider": "flexy",
    "status": "success",
    "mydata_mark": 400001972081610,
    "mydata_uid": "A2C1DBB4600F9CF22CCE6370CEDF72036220B39A",
    "qr_code_url": "https://mydataapidev.aade.gr/TimologioQR/QRInfo?q=…",
    "issuer_vat_number": "<VAT NUMBER>",
    "counterpart_vat_number": "801434350",
    "total_gross_value": "12.40"
    // … and more fields, e.g. document_data with the whole document as you sent it
  }
}

Field	Meaning
`status`	`success`: AADE registered the document.
`mydata_mark`	The MARK (unique registration number) AADE assigned.
`mydata_uid`	The document's UID in myDATA.
`qr_code_url`	The QR link, which opens the document at AADE.
`id`	The document's identifier at Flexy.

What the example contains

Value	Meaning
`provider: "flexy"`	Flexy transmits the document to AADE as the provider.
`provider_details.document_type: "1.1"`	Sales Invoice.
`provider_details.payment_method_type: 3`	Paid in cash (myDATA code `3`) for the whole payable amount.
`issuer`	The business issuing the invoice. Of its details, AADE receives the VAT number; the name and address can stay as they are.
`counterpart`	The invoice's customer: a test customer (VAT `801434350`). It must differ from the issuer.
`items`	One line: 1 piece × €10.00, 24% VAT (VAT category `1`), income classification `category1_1` / `E3_561_001` (wholesale).
`totals`, `tax_breakdown`	€10.00 net + €2.40 VAT = €12.40. They must agree with the lines.

Something is wrong

HTTP	`code`	Cause	What to do
`400`	`required`	A field is missing. `attr` says which, e.g. `aa` or `items.0.description`.	Add the field.
`400`	`invalid`	The amounts do not agree with each other, or the date is in the future. `detail` explains exactly what.	Fix what `detail` mentions.
`400`	`provider_validation_error`	AADE rejected the document; `detail` carries its message. With `It has already been sent for another invoice`, this `aa` was already sent. With `Issuer must be different from counterpart`, the issuer has the customer's VAT number.	For a new `aa`, reload the page and send again. Otherwise fix what `detail` mentions.
`403`	`onboarding_not_approved`	Your registration has not been approved yet.	Email us at [email protected].
`500`	`error`	An error on Flexy's side, e.g. your test account is not fully set up.	Email us at [email protected].

For 401 errors see step 1.

Continue with step 3: the same invoice, paid by card.