These are both very nice projects! Ive unfortunately learned too late with hister that the browser bookmark ingestion expects the binary to be local, instead of on a server/vm. But other than that i'm glad these two projects seem like they complement each other.
You can configure the server URL for the extension by clicking on the cogwheel icon on the extension popup or by visiting the extension's settings page. Servers/VMs are fully supported even with user handling.
Oh, you mean the bookmark import? You can specify the Hister server with the -u/--server-url flags from the command line. Check hister --help for more details
Keep up the good work. If you allow a suggestion: implement an xpath or css selector engine (check searx as a reference), so you can quickly integrate quite a few search engines directly from the default searx config.