An MX record validator checks that your Mail Exchanger DNS records follow the correct format with valid priority numbers and properly formatted hostnames. Paste one or more MX records below to validate syntax, detect duplicate priorities, and identify common email providers like Google Workspace, Microsoft 365, Zoho, and ProtonMail.
MX Record Syntax Reference
Format: PRIORITY HOSTNAME
- Priority: integer 0-65535 (lower number = higher priority)
- Hostname: fully qualified domain name (no IP addresses)
- Hostname should NOT end with a trailing dot in this format
- Multiple records allowed; unique priorities are best practice
- Equal priorities = load balancing (intentional)
Examples:
10 aspmx.l.google.com 20 alt1.aspmx.l.google.com 30 alt2.aspmx.l.google.com
How to Use the MX Record Validator
MX records are critical DNS entries that direct email traffic to the right mail servers for your domain. A misconfigured MX record means email gets bounced, delayed, or sent to the wrong server — this MX record validator catches formatting errors before they cause deliverability problems.
Step 1: Get Your MX Records
Find your domain's current MX records by running nslookup -type=MX yourdomain.com or dig MX yourdomain.com in your terminal. Alternatively, use a DNS lookup service or copy directly from your DNS provider's control panel.
Step 2: Paste and Validate
Paste your MX records into the textarea, one record per line. Each record should follow the format: PRIORITY HOSTNAME (for example, 10 mail.example.com). Click "Validate MX Records" to check syntax, priority validity, hostname format, and detect known email providers.
Understanding Priority Numbers
The priority number determines which server receives email first — lower numbers have higher priority. A typical Google Workspace setup uses priorities 10, 20, 30, 40, and 50. Microsoft 365 uses a single record at priority 0. If you have multiple records with the same priority, email is distributed randomly between them for load balancing — this is valid but the tool will note it as informational.
Common Email Provider Detection
The validator automatically recognizes MX hostnames for major providers: Google Workspace (*.google.com), Microsoft 365 (*.mail.protection.outlook.com), Zoho Mail, ProtonMail, and Mimecast. This helps confirm your DNS is pointing to the correct provider.
FAQ
What is an MX record?
An MX (Mail Exchanger) record is a DNS record that specifies which mail servers accept incoming email for a domain. Each MX record has a priority number (lower = higher priority) and a hostname pointing to the mail server.
What format should MX records be in?
Each MX record should be on its own line in the format: PRIORITY HOSTNAME. For example: '10 mail.example.com' or '20 mail2.example.com'. The priority is a number from 0 to 65535, and the hostname must be a valid domain name.
Why do I have multiple MX records with the same priority?
Having multiple MX records with the same priority is intentional for load balancing. When priorities are equal, sending mail servers choose randomly among them, distributing the incoming mail load across multiple servers.
Is this tool free to use?
Yes, the MX Record Validator is completely free. Paste your MX records and get instant validation with provider detection. No account or signup required.
Is my data safe?
All validation runs entirely in your browser. Your MX records are never sent to any server. The tool processes everything locally and privately.
Can this tool query live DNS records?
This tool validates the format of MX records you paste. For live DNS lookups, use our DNS Records Checker which queries actual DNS servers. This tool focuses on syntax and format validation.