> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vouch.expert/llms.txt
> Use this file to discover all available pages before exploring further.

# MX Records Verification

> Verify domain mail server configuration

## Overview

MX (Mail Exchange) record verification checks whether the email domain has properly configured mail servers in its DNS records. Without valid MX records, a domain cannot receive emails.

<Note>
  This is typically configured as a **BLOCK** check since emails to domains without MX records will always bounce.
</Note>

## What Are MX Records?

MX records are DNS entries that specify which mail servers handle email for a domain. When someone sends an email to `user@example.com`, the sending server looks up the MX records for `example.com` to find where to deliver the message.

## API Response

```json theme={null}
{
  "checks": {
    "mx": {
      "pass": true,
      "latency": 45.3
    }
  }
}
```

For unreachable MX servers:

```json theme={null}
{
  "checks": {
    "mx": {
      "pass": true,
      "latency": 120.1,
      "error": "mx_unreachable"
    }
  }
}
```

<ParamField path="pass" type="boolean">
  Whether the domain has valid MX records
</ParamField>

<ParamField path="latency" type="number">
  DNS lookup time in milliseconds
</ParamField>

<ParamField path="error" type="string">
  Optional error code (e.g., `mx_unreachable` if DNS lookup fails)
</ParamField>

## Configuration

<Card title="BLOCK" icon="ban" color="#ef4444">
  Always BLOCK emails to domains without MX records - they cannot receive email.
</Card>

## Next Steps

<CardGroup cols={2}>
  <Card title="Syntax" icon="code" href="/validation/syntax">
    Validate email format
  </Card>

  <Card title="Disposable" icon="trash" href="/validation/disposable">
    Block temporary emails
  </Card>
</CardGroup>