Substack

Substack is closed and opinionated: 10% revenue cut, no API, no custom domains for free, but distribution and recommendations are real. Largely outside the developer toolchain conversation.

Growth work lives or dies on targeting and measurement. What matters is whether behavioral triggers can be built without engineering time, whether the event stream supports attribution past the open, and whether deliverability holds when broadcast volume shares a reputation with product email.

Against behavior-triggered journeys, broadcasts, and winback campaigns measured on revenue, Substack covers scheduling and the suppressions API, and does not cover event stream, operating track record, and multi-tenant support. Whether that gap matters depends on how central those are to the build.

• Scheduling: Yes
• Event stream: No
• Deliverability: Reasonable for content-driven newsletters.
• Operating since: 2017
• Suppressions API: Yes
• Best published rate per 1,000: Tiers not published in comparable form
• Multi-tenant: No
• Free tier: Free, 10% of paid subscriptions
• Starts at: 10% revenue cut

Reasonable for content-driven newsletters.

Writers who prioritize distribution over flexibility.