ESP Deliverability Report
Updated Apr 1, 2026
Postmark
Transactional email built for speed and reliability
Deliverability Grade
Excellent email deliverability practices
30%
Primary Inbox
55%
Promotions Tab
10.8%
Avg Spam Rate
Transactional ESP
Platform Type
Shared IPs
Available
Dedicated IPs
Shared only
IP Warmup Required
No
Price Range
Mid-range
Dedicated IP Min Volume
Not offered (shared-only philosophy)
Authentication & DMARC Alignment
SPF Auto-Configured
Yes
DKIM Auto-Configured
Yes
Custom Sending Domain
Yes
DMARC Alignment Notes
Postmark requires domain signature authentication and enforces sending domain verification. DMARC alignment passes correctly out of the box. Postmark is strict about authentication — unsigned messages are rejected.
Deliverability Features
- Dedicated message streams (transactional vs. broadcast)
- First-class bounce processing API
- Spam complaint dashboards
- Email open and link tracking
- Retention-based message archiving
- 45-day email log retention
Shared IP Reputation
Postmark uses separate message streams — transactional and broadcast — with isolated IP pools. They enforce strict sending policies: no marketing from transactional streams. This keeps their pools among the cleanest in the industry. Strict compliance review for new accounts.
Best For
Inbox Placement Breakdown
Benchmarks based on InboxEagle seed list testing data across ecommerce and SaaS senders. Individual results vary based on list quality, engagement, and domain reputation.
Key Takeaways for Postmark Senders
Postmark scores a Grade A with a 10.8% average spam rate and 30% Primary inbox placement.
Configuring a custom sending domain is straightforward — do this before scaling sends.
See Your Actual Postmark Inbox Placement
Benchmarks show averages. InboxEagle shows you exactly where your Postmark emails land — Gmail Primary vs. Promotions vs. Spam — across 20+ mailbox providers after every send.
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