Free SPF Record Checker — Validate Your SPF Setup

What is an SPF Record?

An SPF record is a TXT record published in your domain’s DNS that lists the IP addresses and hostnames authorized to send email for that domain. When a receiving mail server gets a message, it checks the SPF record of the sender’s domain to verify the email came from an approved source.

Without a valid SPF record, your emails are more likely to be flagged as spam or rejected outright. SPF is one of three core email authentication protocols alongside DKIM and DMARC.

SPF Best Practices

• Stay under 10 DNS lookups. The SPF specification limits you to 10 DNS-querying mechanisms (include, a, mx, redirect, exists). Exceeding this causes a permanent error (permerror) and your SPF check will fail.
• Use ~all or -all. End your SPF record with ~all (softfail) or -all (hardfail) to tell receivers how to handle unauthorized senders. Avoid +all which allows anyone to send as your domain.
• Publish only one SPF record. Having multiple SPF TXT records on the same domain causes a permerror. Merge all mechanisms into a single record.
• Keep your record under 255 characters per string. While DNS allows multiple strings in a single TXT record, some resolvers have trouble with very long records. Use IP ranges (CIDR) instead of listing individual IPs when possible.
• Pair SPF with DKIM and DMARC. SPF alone is not enough. Combine it with DKIM for message integrity and DMARC for policy enforcement and reporting.

Common SPF Mechanisms