Letter
6.2#138 in email marketing softwareFree planFree planWebAPI
VisitLetter vs Substack
What both publish
| Fact | Letter | Substack |
|---|---|---|
| Audience segmentation | Yes | Yes |
| Email automation | Yes | Yes |
| Free plan | Yes | Yes |
| Integrations | The integrations page lists Zapier, Facebook Lead Ads, Segment, PostHog, Make, and Tally. | Official integrations include RSS, podcast distribution to Apple and Spotify, Google Analytics 4, Google Tag Manager, X and Facebook pixels, Google site verification, YouTube and LinkedIn account connections. |
| Purpose | Letter describes itself as an email marketing automation platform for SaaS, covering lead capture, event-driven sequences, broadcasts, and transactional email. | Substack is a publishing platform for writers, creators, and subscribers. |
Letter plans
- FreeFree
Substack plans
- Free publishingFree
- Free to startFree
- Custom domain$50, paid once
- Paid subscriptions—
Pick Letter if…
You want what its maker publishes above — check its page for the details.
Pick Substack if…
Substack suits writers, journalists, podcasters, video creators, experts, educators, and media companies building a direct subscriber audience. It is useful for creators who want multiple media formats, audience discovery, segmentation, email automation, and paid subscription options.