What BIMI does + why it matters#
BIMI shows your verified brand logo next to your messages in supporting inboxes. Recipients see your logo (not the generic envelope icon) before they open. The effect:
- Open rate lift of 7-15% measured across multiple senders (Yahoo published case study; matches our customer reports)
- Trust signal — receivers learn "this is the real brand" at glance
- Phishing resistance — fake-brand emails can't display the real logo
Supported clients (as of 2026): Gmail (US/EU), Yahoo, Apple Mail (iOS 16+, macOS Sequoia+), Fastmail. Microsoft / Outlook implementation is in pilot.
The 4 prerequisites#
| Prerequisite |
Required state |
| DMARC at p=quarantine or p=reject |
Not p=none. Receivers won't show BIMI if your DMARC is in monitor-only mode. |
| SVG-formatted logo |
SVG Tiny PS profile (a specific BIMI variant). Most agency logos need re-exporting. |
| DNS record for BIMI |
TXT record at default._bimi.yourdomain.com |
| VMC (Verified Mark Certificate) |
Required for Gmail; optional for Yahoo / Apple. ~$1500/yr per domain from Entrust or DigiCert. See BIMI with VMC cost walkthrough. |
If you don't have all 4, BIMI won't display. Start with DMARC enforcement → SVG export → DNS record → VMC (if going to Gmail).
Step 1: Confirm DMARC enforcement#
Open your sending-server detail and verify DMARC chip is Green:
The auth chips on the sending-server detail#
Open Settings → Sending servers → click your active server. The toolbar shows the live SPF / DKIM / DMARC chip status:
- Green chips on all three = receiving servers can confirm you're authorized to send from this domain.
- Any chip red = receiving servers immediately downgrade reputation. Click Verify domain in the toolbar to walk through the DNS-fix wizard.
Your DMARC policy must be p=quarantine or p=reject (NOT p=none). Check with:
dig TXT _dmarc.yourdomain.com +short
# Look for: v=DMARC1; p=quarantine; rua=...
# or: v=DMARC1; p=reject; rua=...
If still on p=none, see DMARC enforcement migration for the staged progression.
Step 2: Export your logo as BIMI-compatible SVG#
BIMI requires SVG Tiny 1.2 Portable Secure (SVG Tiny PS). Standard SVG won't work — Gmail/Yahoo will reject.
Constraints:
- Aspect ratio: 1:1 (square)
- No scripts (no
<script> tags)
- No external font references (embed paths instead)
- No
<image> elements with external URLs (embed inline base64 if needed)
- Single XML element root
- Total file size <32KB
Most agency-exported logos need rework. Either:
- Ask your designer to re-export as SVG Tiny PS (most adobe-illustrator users handle this with the right preset)
- Use a BIMI logo conversion service (Entrust + DigiCert both offer paid prep services)
- Self-validate via the BIMI Inspector — free online tool
Host the SVG at a publicly-accessible URL on your domain, e.g. https://yourdomain.com/bimi/logo.svg.
Step 3: Publish the BIMI DNS record#
At your DNS host, add:
Type: TXT
Name: default._bimi.yourdomain.com
Value: v=BIMI1; l=https://yourdomain.com/bimi/logo.svg; a=https://yourdomain.com/bimi/vmc.pem
TTL: 3600
Two parameters:
l= — the URL of your SVG logo (Step 2)a= — the URL of your VMC certificate (Step 4; OPTIONAL for non-Gmail)
If skipping VMC (Yahoo / Apple only): omit the a= parameter:
v=BIMI1; l=https://yourdomain.com/bimi/logo.svg
Step 4: Get a VMC (for Gmail support)#
VMC = Verified Mark Certificate. Issued by Entrust ($1500/yr) or DigiCert ($1500/yr). Required for:
- Gmail (US/EU)
- Yahoo (recommended; not strictly required)
- Apple Mail (recommended; not strictly required)
Process: trademark verification (your logo must be a registered trademark in your jurisdiction). 4-8 weeks from application to issued certificate.
After issuance:
- Host the VMC at
https://yourdomain.com/bimi/vmc.pem (or any URL on your domain)
- Add the
a= parameter to your BIMI DNS record
Step 5: Verify in Gmail#
Send a test email to a Gmail address you control. After ~30 seconds (Gmail's BIMI lookup cache), open the message — your logo should appear in the sender column.
If not appearing:
- Check DMARC pass at receiver (open "Show original" → look for "DMARC: PASS")
- Verify BIMI DNS record is published:
dig TXT default._bimi.yourdomain.com +short
- Verify SVG is publicly accessible:
curl -I https://yourdomain.com/bimi/logo.svg
- Verify VMC is publicly accessible (if going Gmail):
curl -I https://yourdomain.com/bimi/vmc.pem
- Wait 1-2 hours — Gmail's BIMI cache takes time to refresh on first publish
Common UI signals + fixes#
| Symptom |
Likely cause |
UI fix |
| BIMI DNS record published but logo not showing |
DMARC still at p=none |
DMARC must be quarantine/reject |
| Some Gmail recipients see logo, others don't |
Cache propagation in progress |
Wait 24-48h; verify your test recipient's Gmail account isn't cached |
| Logo appears in Yahoo/Apple but not Gmail |
Missing VMC |
Apply for VMC via Entrust or DigiCert |
| SVG file 404s |
Hosted at wrong path |
Confirm public access: curl -I https://yourdomain.com/bimi/logo.svg returns 200 |
| SVG file accessible but Gmail says "BIMI logo invalid" |
Not SVG Tiny PS format |
Re-export with the BIMI-compatible profile; validate via bimigroup.org |
| Logo appears for some campaigns but not others |
Different sending domains used per campaign — check BIMI record on each |
Each unique From: domain needs its own BIMI record |
Cost-benefit math#
| Cost |
Benefit |
| VMC: $1500/yr |
10% open rate lift on Gmail (largest share of B2C email) |
| DesignerSVG rework: 2-4 hours |
One-time cost |
| DNS record setup: 30 min |
One-time cost |
| Trademark application (if not yet registered): $250-$2000 |
Required for VMC anyway; useful for brand protection |
| Ongoing maintenance: minimal |
Just renewal of VMC each year |
For a list of >100k subscribers, BIMI typically pays back within 3-6 months from incremental open rate alone.
Advanced: multi-subdomain BIMI, fallback patterns, and BIMI without VMC limits
Per-subdomain BIMI:
If you send marketing from mail.brand.com and transactional from txn.brand.com, each subdomain needs its own BIMI record:
TXT default._bimi.mail.brand.com "v=BIMI1; l=https://yourdomain.com/bimi/marketing-logo.svg"
TXT default._bimi.txn.brand.com "v=BIMI1; l=https://yourdomain.com/bimi/txn-logo.svg"
Different logos per subdomain if branding requires (e.g. marketing logo vs corporate logo).
Selector-based BIMI for fine-grained control:
TXT selector._bimi.brand.com "v=BIMI1; l=https://.../variant-a.svg"
In your AcelleMail email headers, set:
BIMI-Selector: selector
Receivers query the matching DNS record. Allows A/B testing different BIMI logos.
BIMI without VMC — supports Yahoo + Apple Mail; NOT Gmail. Some senders skip VMC initially to get partial adoption + revisit Gmail-VMC after measuring impact:
TXT default._bimi.brand.com "v=BIMI1; l=https://yourdomain.com/bimi/logo.svg"
Result: Yahoo + Apple display the logo; Gmail shows the default initial-letter circle.
SVG accessibility checklist:
✅ Single root <svg> element
✅ viewBox attribute set (e.g. viewBox="0 0 64 64")
✅ Aspect ratio 1:1
✅ <title> element for accessibility
✅ No scripting
✅ No external resources
✅ <32KB total
Multi-region BIMI — Gmail caches the DNS lookup per-domain globally; can't serve different logos per region from one BIMI record. If you need per-region logos, use selector-based BIMI (above) with per-region selector values in email headers.
Performance impact — BIMI lookup adds ~50-100ms latency at receive time. Gmail caches aggressively after the first lookup. For high-volume senders this is invisible.
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