MailCheck.ai API

⭐ Beginner's Pick Email / No Auth Required Beginner HTTPS
Free to Use Varies (check documentation)

Overview

MailCheck.ai (powered by UserCheck) is a free API that detects whether an email domain belongs to a known temporary or disposable email provider, helping prevent fake sign-ups without requiring authentication. It checks a continuously updated blocklist of throwaway email domains and returns a simple boolean result. No API key is needed for the basic disposable-check endpoint.

💡

Beginner Tip

MailCheck.ai is one of the simplest no-auth APIs available — just append a domain to the URL and you get back a JSON object with a disposable field. Use it to block throwaway email addresses from your sign-up form with a single fetch call.

Available Data

email delivery status
message ID
bounce/complaint data
open/click tracking
event dates and names
holiday lists by country

Example Response

JSON Response
{
  "message_id": "msg_abc123def456",
  "status": "delivered",
  "to": "[email protected]",
  "subject": "Welcome!",
  "timestamp": "2025-01-15T10:30:00Z"
}

Field Reference

domain The domain name that was checked against the disposable email blocklist
mx True if the domain has valid MX records configured, indicating it can receive email
disposable True if the domain is on the known disposable or temporary email provider blocklist
alias True if the domain appears to be an email alias or forwarding service rather than a primary mailbox provider

Implementation Example

const url = "https://www.mailcheck.ai/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

False positives — legitimate domains flagged as disposable Some corporate or educational domains share infrastructure with disposable providers
Warn the user rather than hard-blocking; display a message like "This looks like a temporary email — are you sure?" instead of rejecting outright
CORS blocked in browser requests Direct browser requests to external APIs are blocked by browser security policies if CORS headers are missing
Proxy the check through your own server endpoint rather than calling MailCheck.ai directly from client-side JavaScript
Domain not in blocklist despite being disposable New throwaway domains appear faster than blocklists update
Combine disposable-domain detection with MX record validation — disposable domains often lack proper mail server configuration

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 20/20
🔒 Security 15/15
🛠 Developer XP 15/20
✓ Reliability 7/15
Response Time 52ms

Fully tested on Apr 5, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS UNKNOWN
Category Email
Difficulty Beginner
Verified: 2026-04-07

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