Email Validator
Quickly check if an email address is valid. Validates email format, syntax, and provides detailed feedback on common issues.
Email Address
Validation Results
Enter an email address to see validation results
Email Format Rules
Valid Characters
- •Letters (a-z, A-Z)
- •Numbers (0-9)
- •Special chars: . ! # $ % & ' * + / = ? ^ _ ` {|} ~ -
- •Plus sign (+) for aliases
Length Limits
- •Local part: max 64 chars
- •Domain part: max 253 chars
- •Total length: max 254 chars
- •Must contain exactly one @
Restrictions
- •No consecutive dots (..)
- •Can't start/end with dots
- •Can't start/end with hyphens
- •Valid TLD required (.com, .org, etc.)
Sample Emails
About Email Validator
A comprehensive email validation tool that checks email addresses for proper syntax, format compliance, and common structural issues. This tool uses industry-standard validation rules to ensure email addresses meet RFC specifications and are formatted correctly for reliable delivery.
Why use a Email Validator?
Invalid email addresses can cause delivery failures, bounce rates, and poor user experience in your applications. This validator helps prevent these issues by checking email syntax before processing, saving you from integration problems and ensuring your email lists maintain high quality and deliverability rates.
Who is it for?
Essential for web developers building contact forms, email marketers managing subscriber lists, data analysts cleaning email datasets, and anyone who needs to verify email address validity before storage or transmission. Perfect for both technical and non-technical users who work with email data.
How to use the tool
Enter the email address you want to validate in the input field
Click the validate button to check the email format and syntax
Review the detailed validation results and any specific error messages
Use the feedback to correct any formatting issues if needed
Copy or save valid email addresses for your applications or lists
Frequently Asked Questions
How do I validate an email address?
Paste an email address. The tool runs a multi-layer check: RFC 5321/5322 syntax validation (correct local-part + @ + domain structure, allowed characters, length limits), DNS MX record verification (the domain has mail servers configured to receive mail), and disposable-email detection (the domain is on known throwaway-email-service lists like Mailinator, 10MinuteMail, GuerrillaMail). The result tells you if the address is well-formed and likely to actually receive mail. Validation runs server-side via the edge proxy — no SMTP connection is opened to the receiving server (which would be intrusive and unreliable for many providers).
What characters are valid in an email address?
RFC 5322 allows almost any printable character in the local-part (before the @): letters, digits, and !#$%&'*+-/=?^_`{|}~. Dots are allowed but cannot be consecutive or at the start/end. Quoted strings ('"hello world"@example.com') allow even more, including spaces. Domain part follows RFC 1035 hostname rules: letters, digits, hyphens, dots. Maximum total length is 254 characters. Many real-world mail servers reject technically-valid-but-unusual addresses (quoted strings, comments in parentheses), so 'syntactically valid' doesn't guarantee delivery. This tool errs on the side of being strict-but-practical, accepting what real mail systems accept.
Can I detect fake or disposable email addresses?
Partially. This tool checks the domain against curated lists of known disposable-email providers (Mailinator, TempMail, GuerrillaMail, 10MinuteMail, and dozens of similar services). When the domain matches, the address is flagged as disposable. However, disposable-email services constantly add new domains, and savvy users can run their own private throwaway-mail servers — so detection is good but not perfect. Beyond disposable detection, this tool verifies the domain has valid MX records (the domain can receive mail at all). For paranoid validation, also check the sender IP against the [IP Blacklist Check](/tools/ip-blacklist-check/) tool, and use double opt-in to confirm the user actually controls the address.
Why are some valid emails being rejected as invalid?
Three common causes. (1) Strictness mismatch — RFC 5322 allows characters (! # $ % etc.) that many naïve regex validators reject; this tool follows the spec. (2) Domain has no MX records — technically the SMTP spec allows fallback to A records, but most senders won't bother; the validator flags it as undeliverable. (3) Recent domain registration with DNS propagation delay — the MX is configured but not yet visible to all resolvers. If a user insists their address is valid, accept it with double opt-in: send a verification email and only activate the account after they click the link. Validation reduces friction; opt-in is the ground truth.
Should I check emails on the client or server?
Both. Client-side validation gives immediate feedback as the user types — improves UX, but can be bypassed (attackers can submit any string). Server-side validation is the authoritative check before storing or sending mail. Use the same validation rules in both places: the client-side check is a UX optimization, the server-side check is a security gate. This tool can run from either context (it's HTTPS, no auth needed). For high-volume signup forms, also rate-limit to prevent enumeration attacks where attackers iterate through emails to discover valid ones. See the [Email Deliverability 2026 Guide](/blog/email-deliverability-2026-spf-dkim-dmarc-bimi-warmup/) for end-to-end mailing best practices.
Why do some catch-all addresses pass validation but bounce?
Catch-all addresses (joe.smith@example.com when no 'joe.smith' user exists, but the domain accepts everything) pass MX-level validation because the domain HAS mail servers, but the specific user doesn't. Validation can't distinguish without performing actual SMTP RCPT TO probing, which is intrusive and many servers refuse. The result: the address passes our check but bounces when you actually send mail. This is the gap between 'address is well-formed and the domain accepts mail' (what we can verify) and 'address is a real, deliverable mailbox' (what only the receiving server knows). Double opt-in resolves this — the user must click a link sent to that address.
What's the difference between syntactic and deliverable validation?
Syntactic validation checks 'is this string formatted as an email per RFC 5322?' — fast, deterministic, no network calls. Deliverability validation checks 'will mail to this address actually reach the recipient?' — slow, probabilistic, requires DNS lookups (MX records) and ideally SMTP probing (which mail servers can refuse). This tool does the first two layers — syntax check + MX existence — but stops short of intrusive SMTP probes. For deliverability ground truth, send a verification email and require the user to click a link. The combination of (syntactic + MX + double opt-in) catches >99% of bad addresses without false negatives on legitimate but unusual addresses.
How does this relate to the MX Lookup tool?
Internally, email validation queries MX records as part of its check — same DNS query that [MX Lookup](/tools/mx-lookup/) exposes directly. The difference: email-validator returns a yes/no on the address as a whole, while MX Lookup shows you which mail servers actually handle inbound mail for the domain (useful for delivery troubleshooting, provider identification, and infrastructure auditing). Use email-validator at signup form time. Use MX Lookup when investigating a specific delivery problem ('why isn't my mail to support@vendor.com arriving?'). The [Email Deliverability 2026 Guide](/blog/email-deliverability-2026-spf-dkim-dmarc-bimi-warmup/) explains the full stack: MX, SPF, DKIM, DMARC, BIMI.
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