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Is this documenta valid ID card?

Constaia answers yes, no or review, with the reasons, the fields you need and without keeping a copy. For ID cards, medical certificates, safeguarding certificates, receipts and 14 more types.

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250 free documents a month · no card

  • Processed in the EU
  • Zero retention by default
  • Verdict with reasons
  • mod 23Deterministic validators
POST /v1/analyze

One call. An answer you can act on.

Tell us what the document should be and which rules it must meet. We tell you whether it is, why, and what it contains.

  1. 01

    Send the document and what you expect

    Photo, screenshot or PDF. Set the expected type and the rules: not expired, under 6 months old, in this person's name.

    {
  "expect": "es_dni",
  "checks": {
    "not_expired": true,
    "min_age_years": 18,
    "holder": {
      "full_name": "María García"
    }
  }
}
  2. 02

    We read, classify and check

    European OCR, AI classification and deterministic validators: NIF letter, MRZ, IBAN, dates and totals.

    • NIF check letter
    • TD1 MRZ
    • IBAN
    • Expiry
    • Age of document
    • Holder
    • Totals
  3. 03

    Get the verdict, the file is deleted

    valid, invalid or review with reasons in your language. By default the file is deleted when the analysis ends.

    • ValidRight type and every check passes
    • InvalidWrong type or a critical check fails
    • ReviewLow confidence or doubtful signals: a person should look

Built for people who receive documents every day

We start with sport and non-profits, where documents are mandatory, recurring and expire.

See all

18 document types, with Spanish rules built in

Field templates and validators for the documents people actually ask for. For everything else, your own schema.

Identity

Certificates

Sport

Payments and finance

Civil and family records

See the full catalogue

Verify without keeping a copy

Spain's data protection authority (AEPD) considers collecting or keeping ID copies excessive as a general rule. Constaia lets you check the document without storing it.

Zero retention by default
With storage "none" the file is deleted as soon as the analysis ends. With keep_results false we do not keep the fields either.
Everything in the EU
Servers at Hetzner, Mistral OCR and models on AWS Bedrock in Frankfurt, with no inference outside the region.
Minimum data
From a medical certificate we extract fit, date and licence number. Never diagnoses.
Data processor
Downloadable DPA with the list of subprocessors. Files encrypted with AES-256-GCM per account.

What we do not do: Constaia is not biometric KYC and does not certify that a document is authentic. A correct check letter or MRZ does not prove it. Warnings are signals for you to decide.

Read the DPA →

Ship it in an afternoon

A REST API with JavaScript and PHP SDKs, deterministic test keys and examples for your framework.

5-minute quickstart
curl https://api.constaia.com/v1/analyze \
  -H "Authorization: Bearer $CONSTAIA_API_KEY" \
  -F "file=@dni_valid.jpg" \
  -F 'options={
    "expect": "es_dni",
    "checks": {
      "not_expired": true,
      "holder": {
        "full_name": "María García López"
      }
    },
    "storage": "none"
  }'

Where you already work

SDKs, an upload component for web and mobile, and an MCP server for AI agents.

All integrations

You pay per validated document. That's it.

No subscriptions, no minimums. Credits last 12 months, a full season.

  • Free

    €0

    250 credits a month

  • 1,000 pack

    €30

    €0.030 per credit

  • 5,000 pack

    €125

    €0.025 per credit

  • 25,000 pack

    €500

    €0.020 per credit

  • 100,000 pack

    €1,900

    €0.019 per credit

Packs expire after 12 months. Prices exclude VAT.

See pricing and calculator

Frequently asked questions

Does Constaia verify that an ID is authentic?

No. We check that the document is the expected type, that its data is consistent (check letter, MRZ check digits, dates) and that it meets your rules. That does not prove authenticity: fake documents with consistent data exist. We give you signals, such as a possible screen photo or possible edit, and if you need identity verification with biometrics we recommend a KYC provider.

Do you store documents?

Not by default. With storage "none" the file is deleted as soon as the analysis ends. You can choose "temporary" (deleted after the hours you set) or "persistent" (until you delete it via the API). With keep_results false we do not keep the extracted fields either.

Where is data processed?

In the European Union: infrastructure at Hetzner, Mistral OCR and AI models on AWS Bedrock in the Frankfurt region (eu-central-1), with no cross-region inference.

How much does it cost?

One credit per document of up to 2 pages (an ID card, both sides, is 1 credit). You get 250 free credits a month and packs from €0.019 per credit. classify costs 0.2 credits. We do not charge for failures on our side or for documents rejected for quality before OCR.

Can I test without spending credits?

Yes. ck_test_ keys use a simulated provider with deterministic responses based on the file name (dni_valid.jpg, dni_expired.jpg, blurry.jpg…), free of charge.

What if the verdict is review?

It means confidence is below the threshold or there are doubtful signals. A person should take a look. You can receive these cases via webhook (analysis.review_required).

Does it work for Spanish sexual offences certificates (LOPIVI)?

Yes: we check type, holder, age and whether records exist, and extract the Secure Verification Code so you can check it on the Ministry of Justice website. We do not query that website automatically.

Who is behind Constaia?

Add On Sport S.L., a Spanish company that builds registration and licensing software for sport. Constaia grew out of validating those documents every day.

Make it count.

Create your account, copy the test key and validate your first document in five minutes.

Start freeTalk to sales250 free documents a month · no card