Privacy

Last updated 18 June 2026.

Substrate is built on the principle that your notes are yours. This page explains what data is collected and how it is handled.

Data controller

Substrate is operated by Doug Belshaw. You can reach the data controller at doug@dougbelshaw.com.

What we collect

When you sign up and use Substrate, we store:

• Email address — used to send sign-in links. Never shared with third parties for marketing.
• Notes and content — everything you write in your garden. Stored in your own isolated database.
• IP addresses — logged in the audit trail alongside actions taken, for security purposes.

Sub-processors

To provide the service, we use the following sub-processors:

• Loops.so — delivers transactional sign-in emails. Loops processes your email address solely to send emails you have requested. Loops privacy policy.
• OpenRouter — provides semantic search when enabled. If you use search-by-meaning features, note content is sent to OpenRouter for embedding. OpenRouter does not store or train on this data. OpenRouter privacy policy.

Lawful basis

We process your data on the basis of legitimate interest — delivering the service you signed up for. For transactional email, we rely on the soft opt-in exemption for existing service relationships.

Data retention

Your data is stored for as long as your account is active. If you delete your account, your data is removed from our servers. You can export all your notes as Markdown files at any time from the settings page.

Your rights

You have the right to access, correct, export, or delete your data at any time. To exercise these rights, contact doug@dougbelshaw.com.

Changes

If this policy changes, we will note the update date above and notify active users by email.