Email Syntax Check API — Validate Email Format Instantly
Check if an email address has valid syntax according to RFC 5321/5322 standards. Quick syntax-only validation without DNS lookups. Free API endpoint.
What is Email Syntax Validation?
Email syntax validation checks whether an address conforms to the RFC 5321 and RFC 5322 standards for email addresses. This includes checking the local part (before @) for valid characters, the domain part for proper format, and overall length limits. It's the first and fastest line of defense against invalid email addresses.
How to Use It
Call GET /api/v1/email-syntax?email=user@example.com. Returns { valid: boolean, local_part: string, domain: string, error: string | null }. The check is instant and requires no DNS queries.
Common Invalid Patterns
The API catches missing @ symbol, multiple @ symbols, empty local part, empty domain, invalid characters in local part (spaces, quotes, parentheses), domain with no dot, TLD too short or too long, and overall length exceeding 254 characters.