Rill stores its library on the device and has no telemetry. Feeds, full-article requests, and configured providers make the network requests described in Integrations.

The library can contain private newsletter text, reading history, provider configuration, and hashed client credentials. Treat complete backups as private. The application creates its data directory with owner-only permissions on Unix systems; operating-system disk encryption remains the user's choice.

Article HTML is sanitized. Scripts, forms, frames, and remote media are omitted. Opening an original article or a link hands that URL to the system browser. Feed URLs intentionally support local and private network hosts for self-hosted subscriptions; do not expose the loopback compatibility service to untrusted networks.

Secrets belong to provider sign-in storage or environment variables referenced by name. Never include passwords, tokens, newsletters, or a private database in a public issue. Report vulnerabilities through the repository host's private reporting feature when available. Otherwise, contact the maintainer privately through the channel where the build was obtained.

Security checks cover parser limits, URL schemes, revoked keys, unexpected origins and hosts, migration failures, and provider isolation. See Testing for the procedures. These checks do not constitute an independent security audit.