Free Email Validation API Comparison 2026

const res = await fetch(
  'https://api.zerobounce.net/v2/validate?api_key=YOUR_KEY&email=test@example.com'
);
const data = await res.json();
console.log(data.status);     // "valid", "invalid", "catch-all", "unknown"
console.log(data.sub_status); // "mailbox_not_found", "disposable", etc.

import requests
r = requests.get('https://api.zerobounce.net/v2/validate',
    params={'api_key': 'YOUR_KEY', 'email': 'test@example.com'})
data = r.json()
print(data['status'])      # valid, invalid, catch-all, unknown
print(data['sub_status'])  # mailbox_not_found, disposable, etc.

const res = await fetch(
  'https://emailvalidation.abstractapi.com/v1/?api_key=YOUR_KEY&email=test@example.com'
);
const data = await res.json();
console.log(data.deliverability);     // "DELIVERABLE" or "UNDELIVERABLE"
console.log(data.quality_score);      // 0.0 to 1.0
console.log(data.is_disposable_email.value); // true/false

import requests
r = requests.get('https://emailvalidation.abstractapi.com/v1/',
    params={'api_key': 'YOUR_KEY', 'email': 'test@example.com'})
data = r.json()
print(data['deliverability'])      # DELIVERABLE / UNDELIVERABLE
print(data['quality_score'])       # 0.0 to 1.0
print(data['is_disposable_email']) # {"value": true/false}

async function validateEmailDomain(email, apiKey) {
  const domain = email.split('@')[1];
  const res = await fetch(
    `https://agent-gateway-kappa.vercel.app/v1/agent-dns/all/${domain}`,
    { headers: { 'x-api-key': apiKey } }
  );
  const data = await res.json();
  const mx = data.records?.MX || [];
  const txt = data.records?.TXT || [];

  // Check if domain has mail servers
  const canReceiveEmail = mx.length > 0;

  // Check for SPF record (email authentication)
  const hasSPF = txt.some(r =>
    (r.entries || [r.data || '']).join('').includes('v=spf1')
  );

  // Check for DMARC
  // (query _dmarc.domain separately for full check)

  return { domain, canReceiveEmail, mailServers: mx.length, hasSPF };
}

const result = await validateEmailDomain('user@gmail.com', 'YOUR_KEY');
console.log(result);
// { domain: 'gmail.com', canReceiveEmail: true, mailServers: 5, hasSPF: true }

import requests

def validate_email_domain(email, api_key):
    domain = email.split('@')[1]
    r = requests.get(
        f'https://agent-gateway-kappa.vercel.app/v1/agent-dns/all/{domain}',
        headers={'x-api-key': api_key}
    )
    data = r.json()
    records = data.get('records', {})
    mx = records.get('MX', [])
    txt = records.get('TXT', [])

    can_receive = len(mx) > 0
    has_spf = any('v=spf1' in str(t) for t in txt)

    return {
        'domain': domain,
        'can_receive_email': can_receive,
        'mail_servers': len(mx),
        'has_spf': has_spf
    }

result = validate_email_domain('user@gmail.com', 'YOUR_KEY')
print(result)
# {'domain': 'gmail.com', 'can_receive_email': True, 'mail_servers': 5, 'has_spf': True}

package main

import (
    "encoding/json"
    "fmt"
    "io"
    "net/http"
    "strings"
)

func validateEmailDomain(email, apiKey string) map[string]interface{} {
    parts := strings.Split(email, "@")
    domain := parts[len(parts)-1]

    req, _ := http.NewRequest("GET",
        "https://agent-gateway-kappa.vercel.app/v1/agent-dns/all/"+domain, nil)
    req.Header.Set("x-api-key", apiKey)
    resp, _ := http.DefaultClient.Do(req)
    defer resp.Body.Close()
    body, _ := io.ReadAll(resp.Body)

    var data map[string]interface{}
    json.Unmarshal(body, &data)

    records := data["records"].(map[string]interface{})
    mx, _ := records["MX"].([]interface{})

    return map[string]interface{}{
        "domain":            domain,
        "can_receive_email": len(mx) > 0,
        "mail_servers":      len(mx),
    }
}

func main() {
    result := validateEmailDomain("user@gmail.com", "YOUR_KEY")
    fmt.Println(result)
}