Is Substack Safe?
Privacy Audit 2026

Substack has rapidly grown into one of the most popular newsletter platforms, with millions of subscribers and thousands of paid publications. The platform's direct relationship between writers and readers creates a different privacy model than traditional publishing. This audit examines what data Substack collects, how reader behavior is tracked, and what the growing Notes social feature means for privacy.

What Data Does Substack Collect?

Our analysis of Substack's privacy policy, terms of service, and technical behavior reveals the following categories of data collection. Each item represents data that Substack either explicitly states it collects in its privacy policy or that independent researchers have documented through technical analysis.

• •Email address and subscription preferences
• •Reading engagement metrics (opens, clicks, time)
• •Payment and billing information
• •Social interactions (Notes, comments, likes)
• •Follow relationships and recommendation data
• •IP address and device information
• •Content publishing history for writers
• •Subscriber growth and revenue analytics

Privacy Concerns

Substack collects subscriber email addresses and reading behavior data as part of its newsletter platform. Writers have access to subscriber engagement metrics including open rates, click-through rates, and reading time. While this data helps writers understand their audience, it means reader behavior is tracked and shared with content creators.

Substack uses third-party services for payment processing (Stripe) and email delivery, meaning subscriber data flows through multiple service providers. The platform's recommendation algorithm also analyzes reader behavior to suggest publications, creating a behavioral profile of each reader's interests across the Substack ecosystem.

Substack Notes (their social network feature) collects additional social interaction data including likes, comments, reshares, and follow relationships. This social graph data adds another dimension to the behavioral profile Substack builds of each user, going beyond simple newsletter subscription into social media territory.

Our Privacy Grade: B

Substack earns an acceptable privacy grade. The product provides adequate security and encryption, but there are areas where data collection exceeds what is strictly necessary for the service. The company holds encryption keys to your data, and administrator or employer access to your content is possible.

Substack offers a simpler privacy profile than Medium but still tracks reader engagement. It does not sell advertising, which removes one major incentive for data harvesting. Writers who need full control over subscriber data should consider self-hosted Ghost or Buttondown.

Better Alternatives

If privacy is a priority, consider these alternatives to Substack that offer stronger data protection:

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