Federation enables browsing content from spaces outside the user’s space, specified by quasi-URLs in the shape of !domain.tld/path. An example would be: CHANGELOG.

This enables a few things:

• Browsing other publicly hosted SilverBullet spaces (or websites adhering to its API) within the comfort of your own SilverBullet client. One use case of this is transcluding the Getting Started page in the user’s automatically generated index page when setting up a fresh space.
• Referencing other spaces for other purposes, which is leveraged in Libraries.

How it works

Effectively, any page link starting with ! is rewritten as follows:

• Replace the initial ! with https://
• Append .md at the end

The resulting URL is then fetched and displayed in the editor in read-only mode. This means that you can navigate to any markdown file on the (public) Internet.

For example: https://raw.githubusercontent.com/silverbulletmd/silverbullet/main/README.md
Can be written to federation syntax as follows: !raw.githubusercontent.com/silverbulletmd/silverbullet/main/README
And used as a link: README

If the target server supports the SilverBullet API (specifically its /index.json endpoint), page completion will be provided as well.

Upon fetching of the page content, a best effort attempt will be made to rewrite any local page links in the page to the appropriate federated paths.

Hosting

Tooling to make hosting public spaces easier is still a work in progress. The way it is enabled on silverbullet.md is by running a dedicated SilverBullet instance in read-only mode (see Configuration#Run mode).