Free email validation API. Detect disposable emails, check MX records, normalize addresses, and catch duplicates — all in one request.
Get Free API KeyEverything you need to validate emails and protect your platform from abuse.
Verify the domain has valid mail servers configured and can actually receive email.
Detect temporary email domains like Mailinator, Guerrilla Mail, and hundreds more.
Normalize Gmail dots and plus aliases to catch duplicate signups automatically.
Detect SimpleLogin, Firefox Relay, Apple Hide My Email, and email aliases.
Identify Gmail, Yahoo, Outlook vs business domains for lead qualification.
Suggest corrections for common typos like gmial.com, outlok.com, and more.
One endpoint. One request. All the data you need.
# Make a request
curl "https://api.checksignup.com/validate?email=test@gmail.com&key=YOUR_API_KEY"{
"email": "john.doe+test@gmail.com",
"normalized": "johndoe@gmail.com",
"domain": "gmail.com",
"mx": ["gmail-smtp-in.l.google.com"],
"valid": {"syntax": true, "mx": true},
"flags": {
"disposable": false,
"forwarding": false,
"free": true,
"catchall": false,
"role": false
},
"typo_suggestion": null
}