Email Validator
Paste an email address to validate format, length limits, domain structure, and optional MX records.
How to use
- Paste one email or one address per line. Format validation updates as you type; nothing is sent to a server for syntax checks.
- Enable Check MX / DNS, then click Check MX / DNS (single) or Check DNS (bulk) to resolve records — lookups run only when you press the button.
- Review parsed parts (local, domain, TLD) and fix errors before export. Use Copy valid or Copy invalid on bulk results.
FAQ
Does this tool verify that an inbox exists?
No. Format checks are local. Optional MX/DNS only confirms the domain has mail routing in DNS, not that a specific mailbox accepts mail.
Why does DNS not run while I type?
DNS lookups are triggered only when you click Check MX / DNS or Check DNS, to avoid rate limits and unnecessary API calls.
Can I validate many emails at once?
Yes. Paste one email per line. Bulk DNS checks up to 25 unique domains per run.
What data leaves my browser?
Format validation stays local. DNS/MX sends only the domain name to this site's DNS API, not full pasted lists as separate email uploads.
How is this different from MX Lookup or SPF Checker?
Email Validator focuses on address syntax plus optional MX. Use MX Lookup, SPF, DKIM, and DMARC tools for full authentication DNS records.
Introduction
An email validator stops bad addresses before they reach your signup form, CRM import, or marketing list. Typos, double dots, missing @, and domains without mail DNS are common — and painful to fix after thousands of rows are already stored.
This tool splits the job into two steps: format validation runs instantly in your browser as you paste, and MX/DNS checks run only when you click a button so lookups stay deliberate and rate-friendly.
What does this email format checker validate?
Syntax and structure follow practical RFC-style rules:
- Exactly one
@separator - Valid local part and domain labels (length limits: 254 total, 64 local, 253 domain)
- No leading/trailing or consecutive dots in the local part or domain
- A plausible TLD (at least two letters)
- Warnings for role addresses (
noreply@,admin@) and reserved zones (.example,.test)
Optional deliverability hint: when you enable Check MX / DNS and click the action button, the tool resolves MX and A records for the domain — the same signal mail servers use to find a recipient host, not proof that a mailbox exists.
Key Features
- Live format feedback for one email or many lines (bulk mode).
- Parsed breakdown: local part, domain, TLD, normalized form.
- On-demand MX/DNS — no automatic DNS while typing.
- Bulk summary with valid/invalid counts, optional DNS column, and copy actions.
- Specific errors instead of a single “invalid email” message.
Common Use Cases
- Cleaning a spreadsheet column before CRM or newsletter import.
- QA-testing signup regex against real-world addresses (
user+tag@domain.co). - Pre-flight checks on support tickets that include customer emails.
- Pairing format validation here with MX Lookup when you only need mail exchanger records.
Best Practices
- Treat format + MX as gates, not proof of inbox existence — SMTP or mailbox verification is a separate step.
- Normalize domains to lowercase when storing; keep display casing if your product requires it.
- Trim whitespace on pasted bulk lines before running Check DNS.
- For SPF, DKIM, and DMARC policy review, use the dedicated SPF Checker, DKIM Checker, and DMARC Checker tools in Email Tools.