For HubSpot deliverability: 1) Connect a custom sending domain in Settings → Marketing → Email → Domains (this enables DKIM signing with your domain), 2) Add HubSpot's SPF include to your DNS, 3) Publish a DMARC record, 4) Enable email health monitoring, 5) Use engagement-based segmentation (HubSpot's contact scoring) to avoid mailing unengaged contacts. Most HubSpot deliverability issues come from sending to unengaged contacts or not configuring custom domain authentication.
HubSpot Deliverability Optimization Guide
HubSpot Authentication Setup
Step 1: Connect Your Sending Domain
- HubSpot → Settings → Marketing → Email → Configuration
- Click Connect a Domain under Email Sending Domains
- Enter your sending domain
- HubSpot provides DNS records:
- DKIM: 2 CNAME records for DKIM signing
- Email validation: MX record for bounce processing
Add all records to your DNS. Wait for propagation.
Step 2: SPF Record
Add HubSpot's SPF include to your domain:
v=spf1 include:spf.hubspot.com [other includes] -all
Step 3: DMARC
If you don't already have DMARC:
_dmarc.yourdomain.com TXT v=DMARC1; p=none; rua=mailto:[email protected]
Step 4: Verify
Send a test marketing email to a personal Gmail. Check headers for:
spf=passdkim=pass(header.d=yourdomain.com, not hubspot.com)dmarc=pass
If DKIM shows hubspot.com instead of your domain, the custom sending domain isn't properly connected.
HubSpot-Specific Deliverability Settings
Email Health Dashboard
Marketing → Email → Health tab monitors:
- Hard bounce rate (must stay under 0.5%)
- Unsubscribe rate
- Spam complaint rate
HubSpot will warn and potentially limit sending if these metrics deteriorate.
Graymail Suppression
HubSpot can automatically suppress contacts who haven't engaged recently: Settings → Marketing → Email → Subscriptions → Don't send to unengaged contacts
Enable this. It's HubSpot's version of engagement-based sending and directly improves deliverability.
Contact Scoring
Use HubSpot's lead scoring to identify engaged vs unengaged:
- Create scoring property based on email opens, clicks, website visits
- Use score in smart lists to segment campaign audiences
- Only send to contacts above a minimum engagement score
Subscription Types
Configure multiple subscription types (Marketing, Product Updates, Newsletter). This lets contacts choose what they receive instead of unsubscribing entirely. Fewer unsubscribes = healthier metrics.
Common HubSpot Deliverability Mistakes
- Not connecting custom sending domain. HubSpot sends as their domain by default. DMARC alignment fails.
- Importing unvalidated lists. HubSpot doesn't validate on import. Clean lists before importing.
- Sending to all contacts. Use engagement-based smart lists, not your full database.
- Ignoring the Health dashboard. Check weekly. Respond to warnings before HubSpot throttles you.
- Not setting up Postmaster Tools. HubSpot's metrics are internal. Google Postmaster Tools shows how Gmail sees you.
Practitioner note: The most common HubSpot deliverability issue I see: companies import 50K contacts from a previous CRM, don't validate them, and send a mass campaign on day one. Bounce rate spikes, HubSpot throttles the account, and it takes 2-3 weeks to recover. Always validate imported lists before sending.
Practitioner note: HubSpot's graymail suppression is off by default. Turn it on. It automatically excludes contacts who haven't engaged recently, improving your engagement metrics without manual segmentation work.
If you need HubSpot deliverability optimized alongside your full email infrastructure, schedule a consultation.
Sources
- HubSpot: Email Authentication
- HubSpot: Email Health
v1.0 · March 2026
Frequently Asked Questions
Does HubSpot handle email authentication automatically?
Partially. HubSpot signs email with their own DKIM by default. For proper DMARC alignment, you must connect your own sending domain and add the DKIM DNS records HubSpot provides. SPF and DMARC must be configured manually on your domain's DNS.
What SPF include does HubSpot need?
Add include:spf.hubspot.com to your domain's SPF record. If you also use Google Workspace: v=spf1 include:_spf.google.com include:spf.hubspot.com -all.
Why are my HubSpot emails going to spam?
Most common causes: sending domain not authenticated (using HubSpot's default instead of your domain), emailing unengaged contacts (no engagement in 90+ days), sending to purchased or imported lists without validation, or sudden volume increases without warmup.
Should I use HubSpot for transactional email?
HubSpot can send transactional email (order confirmations, receipts) but it's not purpose-built for it. For mission-critical transactional, use Postmark or SendGrid alongside HubSpot. HubSpot's strength is marketing automation, not transactional reliability.
How do I check my HubSpot email health?
HubSpot Marketing Hub → Email → Health tab shows bounce rate, unsubscribe rate, and spam report rate. Also set up Google Postmaster Tools for your sending domain to see Gmail-specific reputation data.
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