How to get devices whose primary IP addresses belong to a certain prefix using the API?

[drygdryg]

How do I get a list of devices (dcim.device) whose primary IP addresses are in a certain prefix (ipam.prefix) using the REST API?
If this is not possible, is it possible to get a list of IP addresses that are in a certain prefix?
I can view IP addresses belonging to the prefix through web interface (e.g. https://demo.netbox.dev/ipam/prefixes/1/ip-addresses/), but I haven't found an API method for this.

[candlerb]

How do I get a list of devices (dcim.device) whose primary IP addresses are in a certain prefix (ipam.prefix) using the REST API?

The available filters on /api/dcim/devices/ are in the source code here.

The only query params which relate to primary ip are has_primary_ip, primary_ip4_id and primary_ip6_id.

However...

If this is not possible, is it possible to get a list of IP addresses that are in a certain prefix?

Yes. To find all the IP addresses within prefix 192.168.1.0/24, you would call /api/ipam/ip-addresses/?parent=192.168.1.0%2F24 - code reference here.

Furthermore, you'll find each returned IP address has an assigned_object field, which will tell you the interface and device it belongs to (if any). This solves your original problem, except you may get some IPs you're not interested in.

Adding &assigned_to_interface=true to the query parameters should filter out IPs not assigned to any interface, but you'll still get addresses which are not the primary address of a device, and addresses which are assigned to VM interfaces.

[drygdryg]

Thank you very much for the detailed answer!