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BIMI and VMC Certification · Common Mark Certificates

Common Mark Certificates (CMC) checklist for 2026

Short answer

A complete Common Mark Certificates (CMC) checklist has 4 setup items and 2 things to audit against. Work through setup in order, then schedule a quarterly review.

Setup checklist#

  • ☐ Document at least 12 months of logo use (Wayback Machine snapshots, marketing materials).
  • ☐ Prepare the logo as SVG Tiny PS.
  • ☐ Complete organization validation with DigiCert or Entrust.
  • ☐ Publish the certificate URL in the a= tag of your BIMI record.

Audit checklist#

  • ☐ Confirm you are not: expecting the blue checkmark; CMC does not qualify.
  • ☐ Confirm you are not: changing the logo after issuance, which invalidates the certificate.

Ongoing monitoring#

  • ☐ Weekly: review provider dashboards (Postmaster Tools, SNDS) and bounce logs
  • ☐ Monthly: re-run the setup verification after any vendor or DNS change
  • ☐ Quarterly: full audit against this checklist

Frequently asked questions#

Which providers accept CMC?

Gmail accepts CMC as of 2024. Apple accepts VMC and CMC. Yahoo does not require a certificate.

Can I upgrade from CMC to VMC?

Yes, once the trademark registers. Reissue the certificate and update the a= tag.

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