Context

Users wanted to reference and read pages from other spaces, shared libraries, public/published spaces without copying the content into their own.

Decision

Add federation: a space can link to a remote space via a federated URL prefix, and SilverBullet would sync that external content read-only into the local client, so it could be browsed and queried alongside local pages.

Consequences

Positive

• Let a space pull in shared content (libraries, onboarding material) directly by reference, kept up to date.

Negative / trade-offs

• Significant complexity in the sync and index paths for a relatively niche use case as well as potential security issues: listing timeouts, reference rewriting, Space Lua code injection risks.

Status update

Deprecated and removed (2025). Federation was taken out: the maintenance cost outweighed its limited use, and shared content is better served by other mechanisms (Library, copying, or publishing). It has no direct replacement.

References

• Federation removed: commit dbfc5995 — "More thorough removal of federation".