Email Address Syntax validator
Check the local syntax of one or more email addresses without sending mail or querying a domain.
How to use the Email Address Syntax validator
What does the Email Address Syntax validator do?
Check the local syntax of one or more email addresses without sending mail or querying a domain; It applies this page-specific rule: check the local syntax of one or more email addresses without sending mail or querying a domain.
Which inputs does this validator use?
To check the local syntax of one or more email addresses without sending mail or querying a domain, enter Input, Result; keep every value in the same example; select Check input when the values are ready; Start with a familiar case covered by this rule - Enter the value or list you want to check in the labeled controls - so the expected result can confirm the settings.
How should the validator result be read?
For a result intended to check the local syntax of one or more email addresses without sending mail or querying a domain, enter the value or list you want to check in the labeled controls; read result together with the original input rather than as an isolated answer, and confirm that its units or structure match the intended use.
Does a valid result mean the mailbox exists?
When the goal is to check the local syntax of one or more email addresses without sending mail or querying a domain, this implementation split each mailbox at a single at-sign and apply practical ASCII local-part, domain-label, and total-length rules without querying DNS or a mail server.
Will the tool send an email or query DNS?
When using the page to check the local syntax of one or more email addresses without sending mail or querying a domain, the tool handles only the format and rules described on this page.
Limits and accuracy
When using this validator to check the local syntax of one or more email addresses without sending mail or querying a domain, your work is processed in this browser tab; a passing result confirms the rules tested on this page, but it does not prove that an address, identifier, account, or remote resource exists; keep input until the output has been checked in its intended destination.
What Email Address Syntax validator does
Check the local syntax of one or more email addresses without sending mail or querying a domain.
Enter the value or list you want to check in the labeled controls. The Email Address Syntax validator result stays separate so you can review it before copying, downloading, or using it elsewhere.
Your work is processed in this browser tab. Keep the original whenever a conversion changes formatting, dimensions, or precision.
Frequently asked questions
Does a valid result mean the mailbox exists?
This implementation split each mailbox at a single at-sign and apply practical ASCII local-part, domain-label, and total-length rules without querying DNS or a mail server. The output is per-address syntax status, parsed local and domain parts, and explicit local-rule violations.
Will the tool send an email or query DNS?
The tool handles only the format and rules described on this page. It performs offline syntax analysis only, with no mailbox, DNS, or deliverability verification. It does not contact a remote validation or lookup service.
Are plus addressing and international domains supported?
Input is processed by JavaScript in the current browser tab. Nothing entered in the tool is sent to Plain Tools; keep the original when the transformation is lossy.