About This Tool
Verify any email address format instantly with this free email validator. Paste an email and get a detailed breakdown of the local part, domain, and top-level domain along with RFC 5322 compliance checks. The tool catches formatting errors like consecutive dots, invalid characters, and missing domains, and it flags common typos in popular providers such as Gmail, Outlook, Yahoo, and Hotmail. When a typo is detected, a one-click suggestion lets you fix the address immediately. This is a format validation tool, meaning it checks whether the email follows the correct structural rules. It does not verify deliverability, mailbox existence, or MX records. Use it to clean up mailing lists, double-check form inputs during development, or quickly audit addresses before sending outreach. No signup required, no data collection, and nothing leaves your screen.
How Email Format Validation Works
An email address has two parts separated by the "@" symbol: the local part (before @) and the domain part (after @). The local part can contain letters, digits, and certain special characters like dots, hyphens, and underscores. It cannot start or end with a dot, and consecutive dots are not allowed. The maximum length is 64 characters.
The domain part must be a valid hostname with at least two labels separated by dots. Each label can contain letters, digits, and hyphens, but cannot start or end with a hyphen. The entire domain cannot exceed 253 characters, and each label is limited to 63 characters. The final label is the top-level domain (TLD), such as .com, .org, or .io.
This tool checks all of these rules based on RFC 5322, the standard that defines email address syntax. When a rule is violated, the tool tells you exactly which one and why.
Common Email Typos and Auto-Correction
Misspelling a domain name is one of the most frequent causes of undeliverable email. This validator includes a typo detection database covering the most popular email providers. Common mistakes include:
- gmial.com instead of gmail.com (swapped letters)
- outlok.com instead of outlook.com (missing letter)
- hotmal.com instead of hotmail.com (missing letter)
- yaho.com instead of yahoo.com (truncated domain)
- gmail.con instead of gmail.com (TLD typo)
When a known typo is detected, the tool shows a suggestion with the corrected domain and a button to apply the fix. This is especially useful for cleaning large contact lists or building signup forms where typos lead to bounced messages.
Understanding TLD Verification
The top-level domain (TLD) is the last segment of the domain name after the final dot. Common TLDs include .com, .org, .net, .edu, and country codes like .uk, .de, and .jp. Newer TLDs such as .app, .dev, .io, and .ai are also widely used.
This tool checks the TLD against a list of recognized extensions. If the TLD is not in the list, the tool flags it as unrecognized. This does not necessarily mean the email is invalid, since new TLDs are registered regularly, but it may indicate a typo in the domain extension. An unrecognized TLD combined with a valid format structure deserves a second look before sending.
RFC 5322 Explained for Non-Developers
RFC 5322 is the official specification that defines the format of internet email messages, published by the Internet Engineering Task Force (IETF). It describes what characters are allowed in each part of an email address, how the parts are separated, and what the maximum lengths are.
Key rules from RFC 5322 for email addresses include: the local part allows alphanumeric characters plus special characters like ! # $ % & ' * + / = ? ^ _ ` { | } ~ . - while the domain part follows hostname rules with letters, digits, hyphens, and dots. The total email address length cannot exceed 254 characters. Quoted strings in the local part (like "john doe"@example.com) are technically valid but rarely used in practice. This tool validates the most common unquoted format that covers the vast majority of real-world email addresses.
Use Cases for Email Format Validation
Format validation is the first line of defense against bad email data. Developers use it in registration forms to catch obvious mistakes before the user submits. Marketing teams use it to clean CSV imports before uploading to email platforms like Mailchimp, SendGrid, or HubSpot. QA engineers use it to verify that test data follows proper email syntax.
Format validation alone does not guarantee deliverability. An address like user@example.com passes all format checks but will never receive mail because example.com is a reserved domain. For production email verification, combine format checks with DNS MX record lookups and SMTP handshake verification through a dedicated API service. This tool handles the format layer, which is the fastest and most privacy-friendly check you can run.