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Acceptable use

What apps on Flatstack may not do.

Version 1.0, effective 29 October 2026

Not allowed on Flatstack

  • Bulk or marketing email. Flatstack sends transactional email only: messages a person expects because of something they did, such as sign-in links, receipts and notifications.
  • Illegal content, or content that infringes someone else's rights.
  • Phishing, malware, or impersonating another person or organisation.
  • Crypto mining.
  • Attacking, probing or overloading other systems, including other Flatstack projects and Flatstack itself, or trying to get round plan limits, isolation or security controls.
  • Collecting or processing personal data without a lawful basis, or sending email to addresses that didn't ask for it.
  • Content that sexually exploits children, promotes terrorism, or harasses or threatens people.

Email reputation

To keep email deliverable for everyone, Flatstack watches each project's bounce and complaint rates over its last 500 sends. Sending is suspended automatically if bounces pass 5% or complaints pass 0.1%. Owners are warned at half those rates, and can appeal a suspension from the dashboard.

What we do about breaches

We may remove content, block traffic, or suspend a project or account that breaks this policy, as described in the terms of service. To report abuse of a Flatstack app, email support@flatstack.dev with the app's address and what's happening.