> ## Documentation Index
> Fetch the complete documentation index at: https://signatureapi-daf4ee54.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Attestation and compliance

> Meet legal e-signature requirements for ESIGN, UETA, eIDAS, and country-specific standards like Mexico NOM-151

<Note>
  This page covers e-signature compliance. For [HIPAA compliance](/docs/trust/compliance/hipaa) or [SOC 2 compliance](/docs/trust/compliance/soc2), see their dedicated pages.
</Note>

SignatureAPI is legally binding and compliant with US e-signature regulations (ESIGN and UETA), the European eIDAS regulation (at the SES level), and similar laws around the world.

Some countries have additional legal requirements. Use the `attestation` property to apply a country-specific standard to an envelope.

## Available attestations

| Value       | Description                                                                                               |
| ----------- | --------------------------------------------------------------------------------------------------------- |
| `none`      | No attestation. This is the default and applies to most countries, including the US and EU member states. |
| `mx_nom151` | Mexico NOM-151 compliance. See details below.                                                             |

## Mexico NOM-151

<Tip>To enable NOM-151 attestations for your account, [contact support](https://signatureapi.com/support).</Tip>

[NOM-151](https://www.dof.gob.mx/normasOficiales/6499/seeco11_C/seeco11_C.html) defines the legal standards for data message preservation and document digitization in Mexico.

When `attestation` is set to `mx_nom151`, a preservation certificate in ASN.1 format is attached to the deliverable. SignatureAPI also adds a verification link on the last page of the deliverable. Both the certificate and the deliverable can be verified using any ASN.1 signature verification tool.

<Frame>
  <img src="https://mintcdn.com/signatureapi-daf4ee54/to2kcqhpCDnABjF5/docs/images/mx_nom151.png?fit=max&auto=format&n=to2kcqhpCDnABjF5&q=85&s=5ad2e551079c6e080aa01ffe1ad3b87b" class="border" width="427" height="557" data-path="docs/images/mx_nom151.png" />
</Frame>

To use NOM-151, set `attestation` to `mx_nom151` when creating the envelope:

```json theme={null}
// POST https://api.signatureapi.com/v1/envelopes
// X-API-Key: key_test_...
// Content-Type: application/json

{
    "title": "Contrato",
    "attestation": "mx_nom151",
    "documents": [
        //...
    ],
    "recipients": [
        //...
    ]
}
```

NOM-151 attestation adds \$0.10 per completed envelope.