Email Validator
Validate email addresses for correct format.
How to use the Email Validator
Before sending an email campaign or importing a contact list, it is essential to check that addresses are correctly formatted. This tool validates one or many email addresses instantly in your browser.
- 1
Paste email addresses
Enter one email address per line in the textarea. You can paste a list of dozens or hundreds of emails at once — each line is treated as a separate address.
- 2
Click "Validate Emails"
The tool checks each address against email format rules and marks it as valid or invalid based on its structure.
- 3
Read the results
Each address is shown with a green checkmark (valid format) or a red cross (invalid format), along with a summary count at the bottom showing how many passed.
Frequently asked questions
What makes an email address valid?
A valid email address has a local part (before @), an @ symbol, and a domain part with at least one dot (e.g. user@example.com). It must not contain spaces or invalid characters in the local part or domain.
What is RFC 5322?
RFC 5322 is the Internet standard that defines the format of email message addresses. The full specification is complex; most validators use a simplified but practical subset of the rules that catches the vast majority of formatting errors.
What are the most common email format errors?
Missing @ symbol, spaces in the address, double dots (..), missing domain (e.g. user@), and missing TLD (e.g. user@example with no dot extension) are the most frequent mistakes.
Does passing validation guarantee the email is deliverable?
No. Format validation only checks the syntax — it cannot tell you whether the mailbox actually exists. Confirming deliverability requires sending a test email or using an email verification service that queries MX records.
What about disposable email addresses?
This tool validates format only. Disposable email addresses (like those from guerrillamail.com) are syntactically valid. Use a specialized email hygiene service if filtering out disposable or role-based addresses is important for your use case.
Can I validate a large list in bulk?
Yes — paste any number of email addresses, one per line, and click validate. The summary at the bottom shows how many of your list passed format validation at a glance.