What does the SPF include Mechanism do?

`include` — SPF Mechanism

The SPF include mechanism delegates SPF evaluation to another domain's SPF record. Learn syntax, usage, and lookup-limit implications.

Type
Mechanism

Syntax
include:<domain>

DNS Lookup
Yes — counts toward 10-lookup limit

Example
include:_spf.google.com

💬 What This Mechanism Does

The include mechanism tells receiving mail servers to also check another domain's SPF record. It's how you authorise a third-party email service (like Google Workspace, Mailchimp, or SendGrid) to send on your behalf. If the third party's SPF record passes, your record passes for that mechanism.

When to Use This

Authorising Google Workspace to send from your domain (include:_spf.google.com)
Authorising Microsoft 365 (include:spf.protection.outlook.com)
Authorising a marketing platform like Mailchimp or HubSpot
Referencing a shared company-wide SPF record from a subdomain

⚠️ Watch Out For

Each include counts as one of your 10 allowed DNS lookups. Nesting includes adds up fast.
If the included domain has no SPF record, the result is "permerror" — a hard failure.
You cannot use include to share an IP list; use ip4:/ip6: for that.