Creates tracking numbers for a group. Tracking numbers are the core resource for call attribution - each number can be configured with a destination (termination number), call routing behavior, and a set of features that control how calls are handled, recorded, and verified.

Features objects - when to use which:

There are two places features can be configured: at the number level (features) and at the route level (call_routes.route.features / call_routes.routes[].features). Where you place a feature depends on your routing type.

Basic routing (route_type: "Basic"):

• features (number-level): Configure stop_call, call_verify, scheduled_call_verify, and call_tag_rules here. These apply uniformly to the number regardless of routing.
• call_routes.route.features (route-level): Configure call_record and whisper here. These are specific to how the single route handles the call.

Advanced routing (route_type: "KeyPress", "Geo", "ZipCode"):

• features (number-level): Configure stop_call, call_verify, scheduled_call_verify, and call_tag_rules here. These act as defaults across all routes.
• call_routes.routes[].features (route-level): Configure call_record and whisper per route. This allows different recording or whisper behavior depending on which route handles the call - for example, enabling recording on a daytime route but not an after-hours route.

General guidance:

• Number-level features apply call-agnostically - they fire regardless of which route is matched.
• Route-level features take precedence over number-level features for calls handled by that route.
• If you only need uniform behavior across all routes, prefer setting features at the number level and omitting them at the route level.