es_income_tax_return

Spanish personal income tax return (form 100)

Filed Spanish personal income tax return (form 100): tax year, filer, taxable bases, tax due and result, with receipt number and CSV.

Category: Tax
Country: Spain
Extracted fields: 12 fields
Cost: 1 credit

es_income_tax_returnspecimen

Tax year
Holder name
Holder ID number
Spouse id
Joint
General tax base
Savings tax base
Total tax due
Result

What it checks

National identifiers. Official checksum or format of the number (NIF, CPF, CURP, RUT, SSN…).es_nif, es_nif
Holder. Name, number or date of birth match what you expect.
Secure verification code. Format of the code used to check it with the issuer.

Extracted fields

Tax yeartax_year
Holder nameholder_name
Holder ID numberholder_id
Spouse idspouse_id
Jointjoint
General tax basegeneral_tax_base
Savings tax basesavings_tax_base
Total tax duetotal_tax_due
Resultresult
Receipt numberreceipt_number
Filing datefiling_date
Secure Verification Code (CSV)csv_code

Sample request

curl https://api.constaia.com/v1/analyze \
  -H "Authorization: Bearer $CONSTAIA_API_KEY" \
  -F "file=@document.pdf" \
  -F 'options={
    "expect": "es_income_tax_return",
    "checks": {
      "holder": {
        "full_name": "Carmen Especimen Ruiz"
      }
    },
    "storage": "none"
  }'

Sample response

Fictitious data. Shortened response.

200 OK · application/json

{
  "id": "an_01J9Z3K8QW4T6Y2B7N5M1R0PXC",
  "object": "analysis",
  "status": "completed",
  "livemode": false,
  "document": {
    "type": "es_income_tax_return",
    "label": "Spanish personal income tax return (form 100)",
    "confidence": 0.97
  },
  "verdict": {
    "expected": [
      "es_income_tax_return"
    ],
    "match": true,
    "status": "valid",
    "reasons": [
      {
        "code": "type_match",
        "severity": "info",
        "message": "The document is: Spanish personal income tax return (form 100)."
      }
    ]
  },
  "fields": {
    "tax_year": {
      "value": 2025,
      "confidence": 0.99,
      "validated": true
    },
    "holder_name": {
      "value": "JUAN ESPAÑOL ESPAÑOL",
      "confidence": 0.98,
      "validated": null
    },
    "holder_id": {
      "value": "99999999R",
      "confidence": 0.97,
      "validated": null
    },
    "joint": {
      "value": false,
      "confidence": 0.96,
      "validated": null
    },
    "general_tax_base": {
      "value": 28500,
      "confidence": 0.99,
      "validated": null
    },
    "savings_tax_base": {
      "value": 350.2,
      "confidence": 0.98,
      "validated": null
    },
    "total_tax_due": {
      "value": 4870.55,
      "confidence": 0.97,
      "validated": null
    },
    "result": {
      "value": -312.4,
      "confidence": 0.96,
      "validated": null
    },
    "receipt_number": {
      "value": "1001234567890",
      "confidence": 0.99,
      "validated": null
    },
    "filing_date": {
      "value": "2026-05-10",
      "confidence": 0.98,
      "validated": null
    }
  },
  "checks": [
    {
      "code": "id_number",
      "passed": true,
      "message": "id_number"
    },
    {
      "code": "csv_format",
      "passed": true,
      "message": "The verification code has a valid format."
    }
  ],
  "warnings": [],
  "storage": {
    "mode": "none",
    "file_deleted_at": "2026-09-29T10:00:02Z",
    "expires_at": null
  },
  "usage": {
    "credits": 1,
    "pages": 1
  }
}

FAQ

Does Constaia prove the document is authentic?

No. It checks the type, data consistency and your rules, and flags signals such as a possible edit or a screen photo. That does not prove authenticity.

Is a copy of the document kept?

No, unless you ask for it. With storage "none" (the default) the file is deleted when the analysis ends.

And for the record…

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