BIMI Logo Requirements for Brand Indicators: A Complete Technical Guide

What is BIMI and Why It Matters for Your Brand

Brand Indicators for Message Identification (BIMI) lets email recipients see a verified brand logo next to authenticated messages in their inbox. Think of it as a digital “watermark” that tells the user, “This email really comes from us.” The visual cue boosts open rates, reduces phishing risk, and reinforces brand trust—just like a storefront sign that instantly tells shoppers they’re in the right place.

Core BIMI Logo Specifications

Requirement	Details	Real‑World Example
File Format	SVG (Scalable Vector Graphics) – must be static (no scripts, animations, or external references).	A retail chain uploads a clean, flat‑design SVG of its logo, ensuring it renders sharply on both mobile and desktop.
Dimensions	Minimum 300 × 300 px; recommended 600 × 600 px or larger. Aspect ratio should be 1:1 (square).	A fintech startup creates a 800 × 800 px SVG to guarantee crispness on high‑DPI screens.
Color Profile	Use sRGB color space. Avoid CMYK or Pantone.	A media company converts its logo from CMYK to sRGB, preventing a washed‑out appearance in Gmail.
File Size	≤ 32 KB (compressed). Use tools like SVGO or online optimizers.	A nonprofit compresses its SVG to 28 KB without losing visual fidelity.
Security	Must be signed with a Verified Mark Certificate (VMC) issued by a trusted CA.	A global airline obtains a VMC from DigiCert, linking the logo to its verified identity.
Accessibility	Include a <title> element describing the logo for screen readers.	An e‑commerce brand adds <title>Acme Store Logo</title> inside the SVG.

Pro tip: Even though BIMI uses SVG, you can start with a high‑resolution PNG, trace it in a vector editor (e.g., Adobe Illustrator or Inkscape), and then export a clean SVG.

Preparing Your Logo: Step‑by‑Step Checklist

1. Design in Vector – Create or convert the logo to a vector format.
2. Square Canvas – Ensure the artboard is square; pad the logo if the original shape isn’t.
3. Simplify – Remove gradients, shadows, or complex filters that increase file size.
4. Add <title> – Provide a concise, descriptive title for accessibility.
5. Validate SVG – Run the file through an XML validator to catch stray tags.
6. Compress – Use SVGO (svgo -i logo.svg -o logo.min.svg) or an online optimizer.
7. Check Size – Confirm the final file is ≤ 32 KB.

Publishing the BIMI Record in DNS

BIMI lives in DNS as a TXT record under the _bimi sub‑domain of your domain. The syntax looks like this:

default._bimi.example.com IN TXT "v=BIMI1; l=https://example.com/logo.svg; a=https://example.com/vmc.pem"

Tag	Meaning
v	BIMI version (currently BIMI1).
l	URL to the publicly accessible SVG logo. Must use HTTPS.
a	URL to the VMC (optional but required for most inboxes).
s	Selector for multiple logos (rarely used).

DNS Validation Tips

• TTL: Keep it low (e.g., 300 seconds) while testing, then raise to 3600 seconds for production.
• Propagation: Use tools like dig or online DNS checkers to confirm the record is visible globally.
• SPF/DKIM/DMARC: BIMI only works if your domain already passes these authentication checks.

Testing & Debugging Your BIMI Implementation

1. Check DNS – Run dig TXT default._bimi.example.com to verify the record format.
2. Validate SVG – Use the W3C SVG validator or the “BIMI SVG Validator” provided by major CAs.
3. Confirm VMC – Ensure the certificate chain is complete and matches the domain.
4. Inbox Preview – Send a test email to Gmail, Yahoo, and Outlook accounts; look for the logo in the “Promotions” or “Primary” tab.

Quick win: While waiting for the VMC, you can still publish the BIMI record without the a= tag. Gmail will display the logo once the certificate is attached, but other providers may ignore it.

Common Pitfalls and How to Avoid Them

Pitfall	Symptom	Fix
Non‑square logo	Logo appears cropped or padded oddly in inboxes.	Pad the SVG with transparent space to achieve a 1:1 aspect ratio.
File > 32 KB	BIMI record rejected; no logo shown.	Optimize with SVGO, remove unnecessary metadata, or simplify paths.
Missing <title>	Accessibility warnings in validation tools.	Add <title>Your Brand Logo</title> as the first child of <svg>.
HTTP URL	Gmail refuses to fetch the logo.	Switch to HTTPS; obtain a free TLS cert from Let’s Encrypt if needed.
Invalid VMC	Logo not displayed despite correct SVG.	Verify the VMC is issued for the exact domain and not expired.

Using The Network Tools for BIMI Diagnostics

When you’re troubleshooting BIMI, the right diagnostics can save hours. The Network Tools offers a suite of checks that integrate seamlessly into your workflow:

• DNS Lookup – Instantly query the _bimi TXT record and see the raw response.
• HTTPS Header Inspector – Verify that your SVG URL serves the correct Content‑Type: image/svg+xml and proper TLS configuration.
• DMARC Analyzer – Ensure your domain’s DMARC policy is in “reject” or “quarantine” mode, a prerequisite for BIMI.

Running these checks from a single dashboard eliminates the need to juggle multiple command‑line tools.

Real‑World Implementation: A Case Study

Company: “GreenTech Solutions” (a B2B SaaS provider)
Goal: Deploy BIMI to improve email deliverability and brand perception.

Step	Action	Outcome
1	Created a 600 × 600 px SVG of the leaf logo, added <title>GreenTech Logo</title>.	Clean, accessible vector ready for BIMI.
2	Compressed SVG to 29 KB using SVGO.	Met the size requirement.
3	Purchased a VMC from Entrust for greentech.com.	Certified brand ownership.
4	Published DNS TXT: default._bimi.greentech.com IN TXT "v=BIMI1; l=https://cdn.greentech.com/bimi/logo.svg; a=https://cdn.greentech.com/bimi/vmc.pem"	Record propagated in 12 minutes (TTL 300).
5	Ran The Network Tools DNS Lookup and HTTPS Header checks.	Confirmed DNS record and HTTPS response were correct.
6	Sent test emails to Gmail and Yahoo accounts.	Logo appeared in Gmail’s Primary tab within 30 minutes; Yahoo displayed it after VMC validation (2 hours).
7	Monitored open rates – saw a 4.2 % lift over baseline.	Quantifiable ROI from BIMI adoption.

Checklist Before You Go Live

• Logo is a static SVG, ≤ 32 KB, square, sRGB.
• <title> element present for accessibility.
• VMC issued for the exact domain.
• SPF, DKIM, and DMARC correctly configured (DMARC policy at least quarantine).
• _bimi DNS TXT record published with correct URLs.
• HTTPS endpoints serve proper headers (Content‑Type, TLS version ≥ 1.2).
• Run a final validation with The Network Tools (DNS + HTTPS).

Final Thoughts

BIMI isn’t just a fancy badge; it’s a trust signal that can differentiate your emails in a crowded inbox. By adhering to the logo requirements—static SVG, proper dimensions, tight file size, and a Verified Mark Certificate—you lay the groundwork for a seamless brand experience. Combine those technical steps with robust email authentication, and you’ll see measurable gains in deliverability and engagement.

Ready to verify your BIMI setup? Let The Network Tools handle the heavy lifting: run DNS lookups, inspect HTTPS headers, and confirm your DMARC posture—all from one intuitive dashboard. Your brand’s visual identity deserves to shine—make sure it does, every time an email lands in a user’s inbox.