How to use Email syntax
- 1. Paste an address. One mailbox.
- 2. Read notes. Length and pattern issues.
- 3. Don't treat valid as deliverable. Syntax ≠ inbox.
- 4. Use this in forms. Then confirm with a token email from your backend.
About this tool
HTML type=email is loose. SMTP RCPT is a network call we will not make. This validator sits in the middle: stricter than a toy regex, honest about what it cannot know.
What is checked
A common addr-spec subset, 64/254 length, no consecutive dots in the domain.
What is not
Quotes, comments, IP literals, and unicode domains beyond what the regex allows.