Validate email address format with RFC 5322 compliance checking and MX record lookup suggestions.
An email address is valid only if it matches the local-part@domain shape in RFC 5322, and most failures hide in subtleties: consecutive dots, a missing dot in the domain, or an at-sign in the wrong place. This tool parses the address you paste, reports which rule fails, and adds an MX record note - a domain with no mail server bounces a delivery no matter how clean the syntax. The surprise most users hit runs the other way: plus-tagged addresses such as jane+work@example.com and quoted local parts are legal under RFC 5322 even though many registration forms reject them.
A concrete input and expected output from the current implementation.
Input
jane.doe+newsletter@example.com
Expected output
Valid. The local part 'jane.doe+newsletter' satisfies the dot-atom rule - the plus sign is an allowed character and each dot separates two non-dot characters - and 'example.com' is a well-formed domain. An MX record check on example.com is suggested before relying on delivery, since valid syntax does not confirm the mailbox exists.
Every element here is legal under RFC 5322, which surprises users whose forms refuse plus-tagged addresses. 'jane.doe+newsletter' parses as a dot-separated run of permitted characters, so the address passes even though many signup forms would reject it.
The address is split on the at-sign, then each half is tested against the RFC 5322 grammar. The local part must be a dot-atom: letters, digits, and the punctuation set !#$%&'*+-/=?^_`{|}~ separated by single dots, with no leading, trailing, or consecutive dots - or a quoted string such as "john.doe"@example.com. The domain must be dot-separated labels with no spaces or empty labels.
Mail Exchange (MX) records are DNS entries that tell senders which server accepts mail for a domain. The tool's MX guidance addresses the gap between grammar and reality: a domain with no MX record will refuse your message, while a domain with one still does not prove that your specific address exists. The MX signal is about whether the domain accepts mail, never about whether your mailbox is there.
Because it is valid. The plus sign is an ordinary permitted character in the RFC 5322 local part, and providers such as Gmail route plus-tagged mail to the base address. Websites that reject it are enforcing their own policy, not grammar. If the tool passes it and a site refuses it, the site is the one applying a stricter rule.
Not on that evidence alone. Format validity never proves a mailbox exists; an MX record shows the domain accepts mail for someone, not for you. The only reliable confirmation is a real delivery attempt, and even that can be delayed or silently filtered. Use the tool to rule out syntax problems, then test delivery separately.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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