Stop fake signups at the email field

Check any address for typos, disposable inboxes and domains that can't receive mail. Free, instant, and we never store the address.

What every check covers

Checks run in milliseconds at the edge, cheapest first, so a signup form can call them while the user types.

Syntax

Length limits, valid characters and real domain names, including international domains.

Typos

Suggests gmail.com for gmial.com and .com for .con, so real users aren't lost.

Disposable inboxes

Matches thousands of throwaway domains, and mail servers shared with known burner services.

Mail servers

Looks up MX records live and rejects domains that don't exist, accept no mail, or point to private addresses.

Role addresses

Flags info@, admin@ and noreply@, which rarely belong to one person.

Duplicate accounts

Returns a canonical form that removes Gmail dots and +tags, so one person can't sign up ten times.

One call from your backend

Send the address, get a verdict, a 0–100 score and the reasons behind it. Free accounts get 100 checks a day. Get your API key or read the API docs.

curl -X POST https://api.legitsignup.com/v1/check \
  -H "authorization: Bearer $LEGITSIGNUP_KEY" \
  -H "content-type: application/json" \
  -d '{"email": "jane@gmial.com"}'

Private by design

We never store the addresses you check. Results are cached per domain only, and our logs record the domain and the verdict, never the address.

We don't claim more than we know. We never contact the recipient's mail server, so no result says that a specific mailbox exists.