Some mail providers treat several different-looking addresses as the same mailbox. A period in a Gmail address is invisible to Gmail; a hyphen in a Yandex address is the same character as a dot to Yandex. CleanContact resolves every address you send to one canonical spelling and returns it as the normalized field, right next to the value you sent.
What normalization does
- Lowercases the whole address.
- Resolves known domain aliases to their canonical domain — for example googlemail.com becomes gmail.com.
- For a gmail.com address (after alias resolution), removes every dot from the local part.
- For a yandex.ru address (after alias resolution), turns every hyphen in the local part into a dot.
For every other domain, normalization only lowercases the address — the local part is left exactly as sent. The field is always present in the response, even when nothing changes: for an address that is already in its canonical form, normalized is simply identical to the lowercased value.
Example
A Gmail address typed with a domain alias and dots:
curl -H "X-API-Key: <your-key>" \
"https://api.cleancontact.ru/validate?email=J.Ohn.Doe@GoogleMail.com"{
"value": "J.Ohn.Doe@GoogleMail.com",
"normalized": "johndoe@gmail.com",
"result": {
"status": "Good",
"detail": "Mailbox accepts mail"
}
}googlemail.com resolved to gmail.com, and only then were the dots stripped from the local part — the order matters, since the dot rule applies to the canonical domain, not the one you typed. A Yandex address behaves the same way with hyphens:
curl -H "X-API-Key: <your-key>" \
"https://api.cleancontact.ru/validate?email=Ivan-Petrov@Yandex.ru"{
"value": "Ivan-Petrov@Yandex.ru",
"normalized": "ivan.petrov@yandex.ru",
"result": {
"status": "Good",
"detail": "Mailbox accepts mail"
}
}What it does for you
- Deduplicate your list on the canonical form, not the raw string — j.ohn.doe@gmail.com and johndoe@gmail.com are the same contact, and normalized is what lets you see that.
- Store one row per mailbox — key your database on normalized instead of the address a user happened to type, and repeat signups from the same inbox stop looking like new contacts.
- Nothing to configure — normalization runs on every request, for every API key, at no extra cost.
Normalization is a separate step from the Gmail Dot Trick signal: normalized tells you the canonical form of the address in front of you right now, while gmailDotTrick tells you whether several different spellings of that same mailbox have been submitted before.