Domain Typo Suggestion
smtp-probe automatically suggests corrected domain names when a typo is detected in the domain part of an email address or domain check.
How It Works
The suggestion engine uses a three-stage approach based on the AfterShip algorithm:
- Full-domain match — Compare the input domain against a known list of valid domains using Levenshtein edit distance (threshold: 2).
- Legitimacy fast-path — If both the SLD and TLD are in the known lists, no suggestion is needed (the domain may be valid but not in the full list).
- Split SLD/TLD correction — Correct the second-level domain and TLD separately when they don’t match known values.
When Suggestions Are Triggered
| Scenario | Triggered? |
|---|---|
check / report — MX lookup fails or returns no records | ✅ Yes |
verify — SMTP connection fails (statusCode 0) | ✅ Yes |
verify — SMTP returns 5xx (permanent rejection) | ✅ Yes |
verify — MX lookup fails or returns no records | ✅ Yes |
| Domain is correctly spelled or in the known list | ❌ No |
Domain is a non-email domain (e.g., example.org) | ❌ No |
Example Output
💡 Did you mean gmail.com?Or in JSON/Markdown output:
{
"email": "user@gmil.com",
"suggestion": "user@gmail.com"
}Supported Providers
The suggestion engine covers major email providers including:
- Gmail, Yahoo, Hotmail, Outlook, Live
- ProtonMail, iCloud, AOL, Yandex
- Chinese providers: 163, 126, Sina, QQ
- And many more (120+ domain entries)
Limitations
- Suggestions are based on edit distance and may not cover all possible typos.
- Multi-part TLD domains (e.g.,
.co.uk,.com.au) are handled correctly. - Suggestions are only provided for known provider domains, not arbitrary domains.