When setting up BIMI, a common question I get is whether the size of the brand logo is actually validated. The answer is a definitive yes. However, the validation process is more comprehensive than just checking the file size in kilobytes; it involves a strict set of rules about the logo’s format, dimensions, and content.
BIMI, or Brand Indicators for Message Identification, is an email standard that allows you to display your company's logo next to your messages in the recipient's inbox. It is a powerful tool for increasing brand visibility and building trust, but it only works if you meet all the technical requirements. Your logo is one of the most important pieces of the puzzle.
The specifics of BIMI logo validation
To get your logo to display, you cannot just use any image file. BIMI has very specific requirements that your logo must meet. If any of these are incorrect, the logo simply will not show up. The validation checks a few key things.
- File Format: Your logo must be in the Scalable Vector Graphic (SVG) format. Specifically, it needs to be a restricted version known as SVG Tiny Portable/Secure (SVG P/S).
- Aspect Ratio: The logo must be perfectly square. The exact pixel dimensions do not matter since it is a vector, but the aspect ratio must be 1:1. If it is not, it may be distorted or rejected.
- File Size: The SVG file should be as small as possible, with the official recommendation being under 32 kilobytes (KB).
- Content Restrictions: The SVG file cannot contain certain elements, like scripts, external links, or animations, to ensure it is secure.
How validation works in practice
The validation process for your BIMI logo happens automatically on the server side when you send an email. First, your domain must have a DMARC policy set to an enforcement level of p=quarantine or p=reject. Without this, as DuoCircle points out, "BIMI cannot validate your domain, and so your logo won't be displayed." Your BIMI DNS record contains a URL pointing to your SVG logo file.
When a mailbox provider like Gmail or Apple Mail receives your email, it performs several checks. It verifies your DMARC authentication, finds your BIMI record, fetches the SVG logo, and scans the file to ensure it meets all the strict requirements. This includes the square aspect ratio, small file size, and correct SVG format without any forbidden elements.
Furthermore, if you are using a Verified Mark Certificate (VMC), the logo validation is even more rigorous. A VMC is a digital certificate that proves you have the legal right to use your logo. During the VMC issuance process, the Certificate Authority (CA) will vet your logo to ensure it complies with BIMI standards before embedding it into the certificate. This adds a crucial layer of verification.
What happens if my logo fails validation?
The consequence of a failed logo validation is straightforward: your logo will not be displayed. There is not an error message or a 'close enough' scenario. BIMI is a strict standard, and compliance is all or nothing. If your SVG file is too large, not square, or contains invalid elements, mailbox providers will simply ignore the BIMI record for that message and fall back to showing a generic initial or avatar.
Final thoughts
So, to circle back to the original question: yes, BIMI absolutely validates the size and other attributes of your logo. The term 'size' in the context of BIMI refers not just to the file's weight in kilobytes but also to its 1:1 aspect ratio and its adherence to the secure SVG format. Getting these details right is a non-negotiable step for seeing your logo appear in customer inboxes and reaping the trust and recognition benefits that BIMI provides.
What image format is required for BIMI logos?
What is the recommended size for a BIMI SVG image?
Does BIMI authenticate the logo itself?
What are the specific requirements for an SVG image to be BIMI compliant?
Does BIMI validate the content of the SVG image?
Does BIMI specify a preferred aspect ratio for the logo?
