How Substack does email marketing
SaaS & Tech16 campaigns · www.substack.com · RSS
The app for independent voices
Substack sends about 1.3 campaigns a week, most often on Friday around 1pm US Eastern. Its median subject line runs 43 characters, and 19% carry an emoji.
An early read: 16 campaigns over 85 days, sent Jul 9 to Oct 2, 2026. Treat these as first signs; they firm up past 30 campaigns and six weeks of mail. Each figure is set against the typical brand: the median of 129 brands in the archive with at least 12 campaigns.
- Campaigns a week
- 1.3 64% less than typical (3.6)
- Median subject length
- 43chars 34% more than typical (32 chars)
- Median words
- 1,034 5.9 times typical (175)
- Discount in the subject
- 0% 14 points below typical (14%)
Latest Substack emails
All 16 campaignsWhen Substack sends
Friday is the busiest day (up to 43% of sends). 1pm is the most common hour (up to 43% of sends). Across 14 scheduled campaigns; welcome, cart and order emails are left out because they go out when a subscriber acts. Times are US Eastern.
Day of week
Show days as a tableHide the days table
| Day | Campaigns | Share |
|---|---|---|
| Monday | 0 | 0% |
| Tuesday | 2 | 14% |
| Wednesday | 3 | 21% |
| Thursday | 2 | 14% |
| Friday | 6 | 43% |
| Saturday | 1 | 7% |
| Sunday | 0 | 0% |
Hour of day (US Eastern)
Show hours as a tableHide the hours table
| Hour (US Eastern) | Campaigns | Share |
|---|---|---|
| 12am | 0 | 0% |
| 1am | 0 | 0% |
| 2am | 0 | 0% |
| 3am | 0 | 0% |
| 4am | 0 | 0% |
| 5am | 0 | 0% |
| 6am | 2 | 14% |
| 7am | 1 | 7% |
| 8am | 1 | 7% |
| 9am | 0 | 0% |
| 10am | 0 | 0% |
| 11am | 0 | 0% |
| 12pm | 3 | 21% |
| 1pm | 6 | 43% |
| 2pm | 0 | 0% |
| 3pm | 0 | 0% |
| 4pm | 1 | 7% |
| 5pm | 0 | 0% |
| 6pm | 0 | 0% |
| 7pm | 0 | 0% |
| 8pm | 0 | 0% |
| 9pm | 0 | 0% |
| 10pm | 0 | 0% |
| 11pm | 0 | 0% |
Substack subject lines
The median runs 43 characters across 7 words, against 32 for the typical brand. The words Substack reaches for most: “buffer” and “tami”.
- “A CEO tried to bully a journalist into silence. He failed.” 58 chars · Oct 2
- “Open Tabs with Danny Hieber” 27 chars · Oct 2
- “Model Behavior: George Saunders” 31 chars · Sep 30
- “Open Tabs with Kevin Indig” 26 chars · Sep 25
- “💬 New thread from Tami from Buffer” 34 chars · Sep 24
What Substack sends
Newsletters is the campaign Substack sends most, at 44%; no type is a majority. Welcome, cart and order emails were set off by our own signup, so they do not count toward that.
The stack behind the sends
Substack sends with Substack and publishes a DMARC reject policy.
Sends with
Substack
Domain authentication
Mail failing authentication is rejected outright, the strictest setting.
SPF also authorizes Google Workspace and Mailgun to send as this domain, which usually means other tools sit alongside Substack.
The median Substack campaign carries 3 images.
Compare Substack with Fourthwall
See how Fourthwall send, same industry and measured the same way. Or compare with every SaaS & Tech brand and the whole archive.
How this is measured
Every figure comes from real Substack emails captured in Inbox Archive, not from a survey or a vendor report. Medians and the campaign mix appear once a brand has 12 campaigns archived, and the day and time charts once 12 of them are scheduled sends. “Typical brand” is the median across the 129 brands that clear the same bar, each counted once however much it sends; it uses the brand’s own industry once enough peers qualify. Campaign types are sorted automatically. Discounts are read from subject lines, and a copyable code counts only when one appears in the email, so offers applied at checkout are missed.