The server API is relatively small. The client primarily communicates with the server for file “CRUD” (Create, Read, Update, Delete) style operations.

All API requests from the client will always set the X-Sync-Mode request header set to true. The server may use this fact to distinguish between requests coming from the client and regular e.g. GET requests from the browser (through navigation) and redirect appropriately (for instance to the UI URL associated with a specific .md file).

The API:

  • GET /index.json will return a full listing of all files in your space including metadata like when the file was last modified, as well as permissions. This is primarily used for sync purposes with the client.
  • GET /*.*: Reads and returns the content of the file at the given path. This means that if you GET / you will receive the content of your index page. If the optional X-Get-Meta request header is set, the server does not need to return the body of the file (but it can). The GET response will have a few additional SB-specific headers:
    • (optional) X-Last-Modified the last modified time of the file as a UNIX timestamp in ms since the epoch (as coming from This timestamp has to match the lastModified listed for this file in /index.json otherwise syncing issues may occur. When this header is missing, frequent polling-based sync will be disabled for this file.
    • (optional) X-Created the created time of the file as a UNIX timestamp in ms since the epoch (as coming from
    • (optional) X-Permission: either rw or ro which will change whether the editor opens in read-only or edit mode. When missing, ro is assumed.
    • (optional) X-Content-Length: which will be the same as Content-Length except if the request was sent with a X-Get-Meta header and the body is not returned (then Content-Length will be 0 and X-Content-Length will be the size of the file)
  • PUT /*.*: The same as GET except that it takes the body of the request and writes it to a file.
  • DELETE /*.*: Again the same, except this will delete the given file.
  • GET /.client/*: Retrieve files implementing the client
  • GET /* and GET /: Anything else (any path without a file extension) will serve the SilverBullet UI HTML.