Data Source and Methodology
This tool validates email syntax against the standards defined by the Internet Engineering Task Force (IETF), the governing body for internet standards.
- Authoritative Source: IETF Request for Comments (RFC) 5322
- Reference: RFC 5322: Internet Message Format
- Date: October 2008
All syntax calculations are based on pragmatic regular expressions derived from the rules in this source. This tool performs syntax validation only and does not check if a mailbox exists.
The Formula Explained
An email address is not a simple string; it's a structure composed of two main parts, separated by the '@' symbol. The validation "formula" is a check against this structure:
This tool uses a regular expression (a pattern-matching "formula") to ensure that both the `local-part` and `domain-part` conform to the rules defined by RFC 5322.
Glossary of Variables
- Local-part
- The part of the email address before the `@` symbol (e.g., `john.doe`). It can contain letters, numbers, and certain special characters like
.,_,+, and-. - Domain-part
- The part after the `@` symbol (e.g., `example.com`). This must conform to the standards for a valid hostname, which includes a Top-Level Domain (TLD).
- TLD (Top-Level Domain)
- The final segment of the domain name (e.g.,
.com,.org,.io,.co.uk). - Syntax Validation (This Tool)
- A client-side check to confirm the format of the email is correct. It is instant and private. It does not check if the email address actually exists.
- Server Verification
- A server-side process that checks a domain's MX Records and pings the mail server to see if a specific mailbox exists. This tool does not perform server verification.
How It Works: A Step-by-Step Example
Let's analyze a realistic email address to see how the validation logic works.
Case 1: Valid Email
- Input:
jane.doe+work@example-corp.com - Step 1: Find '@' Symbol: An '@' symbol is present.
- Step 2: Analyze Local-part (
jane.doe+work): Contains only valid characters (letters,.,+). It does not start or end with a.. This is valid. - Step 3: Analyze Domain-part (
example-corp.com): Contains a valid hostname and a TLD (.com). This is valid. - Final Result: Valid Syntax
Case 2: Invalid Email
- Input:
john doe@example.com - Step 1: Find '@' Symbol: An '@' symbol is present.
- Step 2: Analyze Local-part (
john doe): Contains a space. Unquoted spaces are not allowed in the local-part. - Final Result: Invalid Syntax
Frequently Asked Questions
Does "Valid Syntax" mean the email address definitely exists?
No. This tool checks the format (syntax) of the email, not its existence. A 'Valid Syntax' result means the email could exist, but it doesn't guarantee it. Verifying existence requires a separate, server-side check (like an SMTP ping) which this tool does not perform, to protect your privacy.
What is the difference between this tool and a paid email verifier?
This tool performs client-side syntax validation. Paid verifiers perform server-side verification, which involves checking the domain's MX records and pinging the mail server to see if the specific mailbox (e.g., 'john.doe') exists. Our tool is instant and 100% private; paid tools are more thorough but require sending your data to a third-party server.
Is this tool safe to use? Is my email address saved?
Yes, this tool is 100% safe and private. All validation happens directly in your browser (client-side). Your email address is never sent to our server or any third-party server. Nothing is logged or saved.
What are MX Records?
MX (Mail Exchanger) records are special DNS records that tell the world which mail servers are responsible for accepting email for a specific domain. A valid domain must have MX records to receive email.
Why did my email fail the syntax check?
Common reasons for failure include: missing the '@' symbol, having spaces in the address, missing a top-level domain (like '.com' or '.org'), or using special characters incorrectly (e.g., '..' or starting with a '.').
Does this check for disposable email addresses?
Yes. As an added feature, this tool checks the domain against a small, common list of known disposable (throwaway) email providers. If a match is found, the syntax will be marked as valid, but a note will be added.
What about new TLDs like .company or .website?
This validator uses a modern regular expression that supports new generic Top-Level Domains (gTLDs), as long as they are two characters or longer. An email like `contact@my.company` will validate correctly.