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Email complianceReviewed September 7, 2026

What is SPF?

SPF lets a domain owner authorize sending hosts to use its domain in SMTP identities so receivers can check that authorization.

Who this applies to#

  • SPF applies to domain owners and receiving hosts checking authorized sending identities

What SPF requires#

  • Gmail requires at least SPF or DKIM for mail sent to personal Gmail recipients

What this does not require#

  • SPF alone does not authenticate the visible From domain

Common mistakes#

  1. Treating SPF as authentication of the visible From header by itself

SPF checklist#

  • Publish an SPF authorization for sending hosts
  • Check alignment separately
  • Review provider requirements

Commonly confused with#

OnVoard's take#

Treat SPF as one authorization layer, then verify alignment and the receiving provider rules separately.

Official sources#