Sidemail Validator is a free online tool that checks email addresses for validity by examining syntax, domain existence, MX records, disposable provider flags, and common typos. It optionally performs an SMTP handshake to verify server acceptance without sending actual emails.

The validator checks email syntax to confirm proper format (name@domain), verifies domain existence and DNS resolution, confirms MX records for mail reception capability, flags disposable email providers that harm deliverability, detects common typos and suggests fixes, and optionally performs SMTP handshake to check server acceptance.

The tool works by allowing users to paste an email address and optionally select deep SMTP check, then clicking validate to see results in a table format. The SMTP deep check performs a server handshake without sending messages, providing higher confidence in address validity.

Benefits include higher deliverability through accurate validation, clear failure reasons for quick issue resolution, and free online access without login requirements. Use cases include validating individual email addresses before sending communications and cleaning email lists to improve marketing effectiveness.

The tool targets users needing email validation for marketing, sales, or communication purposes, with integrations available through bulk validation tools for larger lists.