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POST
/
v1
/
validate
/
emails
curl -X POST https://www.unosend.co/api/v1/validate/emails \
  -H "Authorization: Bearer un_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "emails": [
      "[email protected]",
      "[email protected]",
      "[email protected]",
      "[email protected]"
    ]
  }'

{
  "total": 4,
  "valid": 2,
  "invalid": 2,
  "risky": 2,
  "summary": {
    "deliverable": 2,
    "undeliverable": 2,
    "risky": 2,
    "unknown": 0
  },
  "results": [
    {
      "email": "[email protected]",
      "valid": true,
      "score": 90,
      "reason": null,
      "checks": {
        "syntax": true,
        "mx_records": true,
        "disposable": false,
        "role_based": false,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "valid",
        "domain": "company.com"
      }
    },
    {
      "email": "[email protected]",
      "valid": true,
      "score": 75,
      "reason": "Role-based email address",
      "checks": {
        "syntax": true,
        "mx_records": true,
        "disposable": false,
        "role_based": true,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "info",
        "domain": "business.com"
      }
    },
    {
      "email": "[email protected]",
      "valid": false,
      "score": 40,
      "reason": "Disposable email address",
      "checks": {
        "syntax": true,
        "mx_records": true,
        "disposable": true,
        "role_based": false,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "temp",
        "domain": "mailinator.com"
      }
    },
    {
      "email": "[email protected]",
      "valid": false,
      "score": 25,
      "reason": "Domain has no mail server (MX records)",
      "checks": {
        "syntax": true,
        "mx_records": false,
        "disposable": false,
        "role_based": false,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "invalid",
        "domain": "nonexistent.xyz"
      }
    }
  ]
}
Pro Feature: Bulk email validation is available on Pro, Scale, and Enterprise plans only. Free plan users should use the single email validation endpoint.

​
Request Body

​
emails
array
required
Array of email addresses to validate. Maximum 1,000,000 emails per request on Pro/Scale/Enterprise plans. Duplicates are automatically removed.
​
check_smtp
boolean
default:"false"
Perform SMTP mailbox verification for each email. Significantly slower but more accurate.
​
check_catch_all
boolean
default:"false"
Check if domains are catch-all (accept any address).

​
Response

​
total
number
Total number of emails validated
​
valid
number
Count of valid emails
​
invalid
number
Count of invalid emails
​
risky
number
Count of risky emails (disposable, role-based, catch-all)
​
summary
object
​
results
array
Array of validation results for each email (same format as single validation)
curl -X POST https://www.unosend.co/api/v1/validate/emails \
  -H "Authorization: Bearer un_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "emails": [
      "[email protected]",
      "[email protected]",
      "[email protected]",
      "[email protected]"
    ]
  }'

{
  "total": 4,
  "valid": 2,
  "invalid": 2,
  "risky": 2,
  "summary": {
    "deliverable": 2,
    "undeliverable": 2,
    "risky": 2,
    "unknown": 0
  },
  "results": [
    {
      "email": "[email protected]",
      "valid": true,
      "score": 90,
      "reason": null,
      "checks": {
        "syntax": true,
        "mx_records": true,
        "disposable": false,
        "role_based": false,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "valid",
        "domain": "company.com"
      }
    },
    {
      "email": "[email protected]",
      "valid": true,
      "score": 75,
      "reason": "Role-based email address",
      "checks": {
        "syntax": true,
        "mx_records": true,
        "disposable": false,
        "role_based": true,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "info",
        "domain": "business.com"
      }
    },
    {
      "email": "[email protected]",
      "valid": false,
      "score": 40,
      "reason": "Disposable email address",
      "checks": {
        "syntax": true,
        "mx_records": true,
        "disposable": true,
        "role_based": false,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "temp",
        "domain": "mailinator.com"
      }
    },
    {
      "email": "[email protected]",
      "valid": false,
      "score": 25,
      "reason": "Domain has no mail server (MX records)",
      "checks": {
        "syntax": true,
        "mx_records": false,
        "disposable": false,
        "role_based": false,
        "free_provider": false,
        "catch_all": null,
        "smtp_valid": null
      },
      "details": {
        "local_part": "invalid",
        "domain": "nonexistent.xyz"
      }
    }
  ]
}

​
Processing Large Lists

For lists larger than 1000 emails, split them into batches: 
async function validateLargeList(emails, apiKey) {
  const batchSize = 1000;
  const results = [];
  
  for (let i = 0; i < emails.length; i += batchSize) {
    const batch = emails.slice(i, i + batchSize);
    const response = await fetch('https://www.unosend.co/api/v1/validate/emails', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${apiKey}`,
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({ emails: batch })
    });
    const data = await response.json();
    results.push(...data.results);
  }
  
  return results;
}
Bulk validation processes emails in parallel (10 concurrent). SMTP checks will significantly increase processing time.