NetBox API

NetBox REST API (using the instance, not administering it)

Operate an existing NetBox through its REST API — batch device moves, renames, cable sweeps, IP assignment. For upgrading the instance, venv drift, rq worker crashes, or reverse-proxy/CSRF config, use the sibling skill netbox-upgrade instead — this skill is only about using NetBox via the API.

Verified against NetBox 4.6.8 (Authorization: Bearer on every call). Never hardcode the token in files — reference it as a placeholder. Access may be IP-restricted at the reverse proxy; if every call 403s with a valid token, that's an allowlist/egress issue, not auth.

Golden rules for API work

1. PRE-VERIFY ids → names with GET before any write batch. Build the plan from a fresh fetch, match every planned object by name, abort on any mismatch. Never PATCH by id from a plan written before the fetch.
2. READ BACK after every batch. Re-fetch and diff against the source document (rack, position, site, name, description). A 200 is not proof the change landed.
3. Batch writes = one Python script, not N tool calls. A single loop (GET-verify → PATCH/DELETE → read-back) survives timeouts and gives an auditable per-object log. Reusable CLI: scripts/netbox_api.py.
4. Wrong field names are SILENT no-ops, not errors — see position below.

The field gotchas (these cost real debugging time)

• The U position field is position (float), NOT rack_unit. NetBox 4.x uses position + face on the Device API. Sending rack_unit returns 200 and changes nothing — always read back.
• OOB IP is a device field, not an IP flag. The GUI checkbox "Make this the out-of-band IP for the device" maps to Device.oob_ip (nullable BriefIPAddress). There is no boolean on the IPAddress schema. Set it via PATCH /api/dcim/devices/{id}/ with {"oob_ip": }.
• primary_ip4 is nullable. A device whose only IP is its OOB/management IP should normally have no primary IP: PATCH /api/dcim/devices/{id}/ {"primary_ip4": null} (200) keeps oob_ip intact. Use this when the IP is "only" the management/OOB IP.
• A device's primary_ip4 cannot be unassigned — 400 Cannot reassign IP address while it is designated as the primary IP. Clear the device's primary_ip4 first.
• The assigned_object brief in GET responses has NO type key — only id/url/display/device/name (±cable/_occupied). To map IPs → devices, match "/dcim/interfaces/" in assigned_object["url"] and read assigned_object["device"]["id"]. Keying on type == "dcim.interface" matches nothing.

Common operations

• Relocate a device to a rack: PATCH /api/dcim/devices/{id}/ with {"rack": , "position": } (add "face": "front" when it matters). For a cross-site move, ALSO send "site": {"id": } and "location": null in the same call, or you'll get 400s:
  • Rack X does not belong to site Y
  • Location Z does not belong to site Y Get `` from GET /api/dcim/racks/?limit=100 (name→id, note each rack's site). PATCH is a partial update — send only the fields you're changing.
• Assign an IP to an interface: PATCH /api/ipam/ip-addresses/{id}/ with {"assigned_object_type": "dcim.interface", "assigned_object_id": } (the assigned_object object field itself is read-only). To unassign, send null for both — but it 400s if the IP is a device's primary_ip4; clear that first.
• Management-IP migration pattern (move + OOB + unassign legacy): one device PATCH sets oob_ip and primary_ip4 to the new IP, then a second PATCH unassigns the legacy IP object. Doing the unassign first 400s while it's still primary.
• Verify IP assignments via the IP object (assigned_object_id), not the interface list view — the interface ip_address/ip_addresses fields can come back empty/missing even when assigned.
• Trim payloads: append &fields=name,rack,position,site to a list endpoint. Note nested objects come back as {"id":…, "name":…} (a dict — use .get("id")).
• Object counts: GET /api///?limit=1 then read .count — cheap way to see if a collection is populated.

Pagination (a real trap)

• List responses carry count, next, previous. Always follow next — never assume the last page.
• GET .../?limit=2000 silently caps at 1000 (server MAX_PAGE_SIZE default). Follow next to get the rest.
• ?name=exact-string on /api/dcim/devices/ uses exact-match (iexact) semantics and may return 0 hits for a name that exists with different casing/form — fetch the full list and filter client-side.
• scripts/netbox_api.py follows next correctly; use its all subcommand rather than hand-paging.

Discovery

• OpenAPI schema: GET /api/schema/ — served as YAML, not JSON. Parse with yaml.safe_load, not json.load.
• Version/status: GET /api/status/ → JSON with netbox-version, django-version, python-version, plugins, rq-workers-running.
• No "Docs" app in 4.6.x: /api/docs/* all 404. When a user says "change the documentation" they usually mean the description/comments fields on existing objects (or relocating objects) — ask which objects.

Verify after a batch

Re-fetch the affected objects and diff against the source document. Spot-check a known device's rack/position/name and an assigned IP's assigned_object_id. Don't close on 200s alone.

Verifying API claims against upstream (no live box needed)

When you can't reach the running instance, check the tagged source instead: raw.githubusercontent.com/netbox-community/netbox/v/netbox/....

• 4.6.x serializer layout is a serializers_/ package — serializers.py at dcim/api/ and ipam/api/ only re-export from it. Device fields: dcim/api/serializers_/devices.py; nested (brief) forms: dcim/api/serializers_/nested.py; IP fields: ipam/api/serializers_/ip.py.
• Pagination defaults: netbox/netbox/config/parameters.py — PAGINATE_COUNT default 50, MAX_PAGE_SIZE default 1000 (both overridable in configuration.py).
• Device validation error strings: dcim/models/devices.py; primary-IP unassign guard: ipam/models/ip.py.

References

• references/netbox-api.md — field-level quick reference (all the field gotchas + common ops in one table-ish doc)
• references/batch-device-operations.md — full verified recipe: relocate 21 nodes, renames, description tags, 68-cable sweep (GET-verify → write → read-back)

Sibling skill

• netbox-upgrade — major-version upgrades, venv/requirements drift, rq worker ImportError: cannot import name 'Connection', and reverse-proxy CSRF 403s (references/proxy-csrf-403-behind-reverse-proxy.md). If the task is fixing the instance rather than driving it via the API, switch there.