Short answer: it's difficult. You can change the url of the project server in
installer.settings.jsonbut you lose the ability to install or update modules served by Backdrop's project server.
You can specify custom URLs for "non-official" contrib/custom modules, by adding the project status url property in the .info file of the module. That should allow you to keep Backdrop core and "official" contrib updated from https://github.com/backdrop-contrib as per usual, while the custom module can get updates from elsewhere. I've never personally done it, so untested. But it's been there since D7 (perhaps even before).
Backdrop CMS contributed projects
Join the group at https://github.com/backdrop-ops/contrib to add your own! - Backdrop CMS contributed projects
I don't see that property mentioned in https://docs.backdropcms.org/creating-modules#info-files but it is mentioned in https://www.drupal.org/node/542202 (last in the list of .info properties).
klonos:
project status url (Only used for custom modules not submitted to drupal.org)
Allows module maintainers to define a URL to check for updates to their module using the Update status module. No module released on drupal.org should define this parameter. URL should point to an XML feed that accepts requests in the form of
http://my.domain.com/projects/{project}/{core}. In that example,project status urlshould be set tohttp://my.domain.com/projects.
klonos: The logic seems to be there. See:
- https://github.com/backdrop/backdrop/blob/fe5c21ced7a7e3bcb9b41df15a7977ee89384a17/core/modules/update/update.fetch.inc#L305
- https://github.com/backdrop/backdrop/blob/fe5c21ced7a7e3bcb9b41df15a7977ee89384a17/core/modules/installer/installer.browser.inc#L193
- https://github.com/backdrop/backdrop/blob/fe5c21ced7a7e3bcb9b41df15a7977ee89384a17/core/modules/installer/installer.browser.inc#L291
- https://github.com/backdrop/backdrop/blob/fe5c21ced7a7e3bcb9b41df15a7977ee89384a17/core/modules/installer/installer.pages.inc#L489
Recent comments
Hi Kevin I am interested assisting you developing a theme by cloning feature from existing WordPress website. Please let me know your suitable time to discuss further...
Create a theme from existing website
I've updated the Zulip link in both places I found it. No need to post again, unless you have something new to say. We'll pull together feedback from all the sources.
Backdrop CMS Core Priorities
Should we post here again, what we posted over there? Or would that unnecessarily duplicate things? The link to a Zulip thread in this initial post leads to an internal one, but there's...
Backdrop CMS Core Priorities
Let's consolidate this with https://forum.backdropcms.org/forum/weekly-dev-meetings-focus-top-wish-list-items-start-march-26-2026
Backdrop CMS Core Priorities
This is a really good idea. I nearly always search on GitHub if I'm not sure of the name. That said, there is still room for improvement in GitHub as many repos have a useless description...
Weekly dev meetings to focus on top wish list items start March 26, 2026.