utility_bill

Utility bill

Electricity, gas, water, internet or phone bill from any country, used as proof of address: supplier, holder, supply address, CUPS/meter point, period and amount.

Category: Proof of address
Country: International
Extracted fields: 16 fields
Cost: 1 credit

utility_billspecimen

Supplier
Supplier tax id
Service type
Holder name
Holder ID number
Supply address
Postal code
Country
Cups

What it checks

National identifiers. Official checksum or format of the number (NIF, CPF, CURP, RUT, SSN…).postal_code
Postal code. Postal code format of the country.
Holder. Name, number or date of birth match what you expect.
Recency. Issued less than N days ago.

Extracted fields

Suppliersupplier
Supplier tax idsupplier_tax_id
Service typeservice_type
Holder nameholder_name
Holder ID numberholder_id
Supply addresssupply_address
Postal codepostal_code
Countrycountry
Cupscups
Contract numbercontract_number
Invoice numberinvoice_number
Issue dateissue_date
Period startperiod_start
Period endperiod_end
Amountamount
Currencycurrency

Sample request

curl https://api.constaia.com/v1/analyze \
  -H "Authorization: Bearer $CONSTAIA_API_KEY" \
  -F "file=@document.pdf" \
  -F 'options={
    "expect": "utility_bill",
    "checks": {
      "max_age_days": 90,
      "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": "utility_bill",
    "label": "Utility bill",
    "confidence": 0.97
  },
  "verdict": {
    "expected": [
      "utility_bill"
    ],
    "match": true,
    "status": "valid",
    "reasons": [
      {
        "code": "type_match",
        "severity": "info",
        "message": "The document is: Utility bill."
      }
    ]
  },
  "fields": {
    "supplier": {
      "value": "ESPECIMEN ENERGÍA S.A.",
      "confidence": 0.99,
      "validated": true
    },
    "supplier_tax_id": {
      "value": "A12345674",
      "confidence": 0.98,
      "validated": null
    },
    "service_type": {
      "value": "electricidad",
      "confidence": 0.97,
      "validated": null
    },
    "holder_name": {
      "value": "JUAN ESPAÑOL ESPAÑOL",
      "confidence": 0.96,
      "validated": null
    },
    "holder_id": {
      "value": "99999999R",
      "confidence": 0.99,
      "validated": null
    },
    "supply_address": {
      "value": "C/ MAYOR 1, 3º A, MADRID",
      "confidence": 0.98,
      "validated": null
    },
    "postal_code": {
      "value": "28013",
      "confidence": 0.97,
      "validated": null
    },
    "country": {
      "value": "ESP",
      "confidence": 0.96,
      "validated": null
    },
    "cups": {
      "value": "ES0021000000000000AA",
      "confidence": 0.99,
      "validated": null
    },
    "contract_number": {
      "value": "123456789",
      "confidence": 0.98,
      "validated": null
    },
    "invoice_number": {
      "value": "FE26-000123",
      "confidence": 0.97,
      "validated": null
    },
    "issue_date": {
      "value": "2026-09-05",
      "confidence": 0.96,
      "validated": null
    },
    "period_start": {
      "value": "2026-08-01",
      "confidence": 0.99,
      "validated": null
    },
    "period_end": {
      "value": "2026-08-31",
      "confidence": 0.98,
      "validated": null
    },
    "amount": {
      "value": 68.42,
      "confidence": 0.97,
      "validated": null
    },
    "currency": {
      "value": "EUR",
      "confidence": 0.96,
      "validated": null
    }
  },
  "checks": [
    {
      "code": "id_number",
      "passed": true,
      "message": "id_number"
    }
  ],
  "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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