Postmark vs Substack
Side-by-side plans, pricing, and feature gates for Postmark and Substack, verified . Postmark is primarily transactional email; Substack is primarily email marketing.
Plans side by side
Every published plan from each vendor, with the headline monthly anchor price. Some prices scale with subscriber count or seats; full detail lives on each tool's page.
Postmark
- Free
100 emails per month, no credit card required
Free - Basic
Entry paid tier with 10,000 emails/month and 5 custom domains
$15/mo - Pro
10,000 emails/month with inbound processing and customizable retention
$16.50/mo - Platform
Unlimited domains and users with the lowest overage rate
$18/mo - High-Volume
Custom pricing for volumes above standard tiers
Custom
Substack
- Standard
Free to publish; 10% of paid subscription revenue
Free
When Postmark wins
- SaaS apps prioritizing receipt and notification deliverability
- Teams that need detailed inbound email parsing alongside outbound sends
- Companies that need 365-day data retention for compliance
Where Postmark is the wrong fit
- Hobby projects with bursty traffic (Mailgun's 100/day or Resend's 3,000/month are friendlier than the 100/month Free cap)
- Marketing teams (use Mailchimp or Kit)
- Buyers who want a single vendor for marketing and transactional email
When Substack wins
- New writers with no list yet who want platform-driven discovery
- Writers who would rather give 10% of revenue than pay a flat $20-100/month with no readers
Where Substack is the wrong fit
- Established creators with a paid list above ~5,000 subscribers; the 10% share exceeds what Kit, Ghost, or beehiiv would charge in flat fees at that scale
- Operators who want full control over deliverability, subscriber data, and migration optionality
- Brands needing automations, segmentation, or marketing tooling
Common questions
- Is Postmark cheaper than Substack?
- Both Postmark and Substack have free or custom entry pricing, so a direct entry-tier price comparison is not meaningful.
- Does Postmark or Substack have a free plan?
- Both have free plans. Postmark: 100 emails per month, no credit card required. Substack: Free to publish; 10% of paid subscription revenue.
- Are Postmark and Substack in the same category?
- No. Postmark is primarily a transactional email tool; Substack is primarily a email marketing tool. They overlap on use case but sit in different primary categories, so the comparison is between adjacent tools rather than direct competitors.
- Which has more plans, Postmark or Substack?
- Postmark ships 5 plans; Substack ships 1. Postmark's longer ladder gives more granular upgrade steps, which can mean smoother price escalation as your team scales.
- Where can I see alternatives to Postmark or Substack?
- Each tool has a dedicated alternatives page on TierGauge with ranked options and verified pricing: /alternatives/postmark for Postmark and /alternatives/substack for Substack. Alternatives are derived from each tool's editor-flagged competitors plus same-category tools we track.
Postmark: https://postmarkapp.com/pricing · Substack: https://substack.com/going-paid
Last verified . Pricing changes between refreshes; confirm at the vendor before purchasing.