RustPBX Basics: IVR — Menus, Schedules, and When to Go External

Every PBX has an IVR. The differences that matter: how flows are authored, how they branch on time and data, and how easy it is to hand a call to an external brain when menus stop being enough. Here’s the RustPBX toolbox, inside-out.

Layer 1: Built-in IVR Flows

Flows live as TOML/JSON files under config/ivr/, or authored visually with the IVR Editor addon (drag-and-drop menus, business-hours control, TTS synthesis, multi-level menus — publish straight into the PBX).

IVR editor console

Inside the editor, each menu has its greeting (audio or TTS), timeout/retry behavior, and one card per DTMF key with its label and action — queue, transfer, sub-menu, voicemail, webhook, or hangup:

IVR editor — root menu with DTMF keys and per-key actions

Nodes cover the classics: play prompt, collect digits, menu branching, route to extension/queue/trunk, voicemail, and record. TTS prompts synthesize through the configured engine, with PBX-wide prompt aliases so third-party trees don’t hard-code engine-specific strings.

Layer 2: Schedules Inside the Flow

Flows branch on business hours, holidays, and night mode — the same schedule model as queues:

Business hours with timezone
A holiday map, each with its own action
Night mode for the daily cycle

One flow serves day and night, and the holiday map means February 17th doesn’t play your January greeting.

Layer 3: Step IVR — Your Code Decides

When menus aren’t enough — CRM lookups, AI decisions, anything dynamic — Step IVR externalizes the flow: each call step POSTs to your provider API, and your code answers with the next action (play, collect, bridge, transfer, hangup):

[ivr.provider]
url = "http://10.0.0.50:8080/ivr/step"
timeout_secs = 10

The protocol handles the hard parts: DTMF with timeouts, voice recognition results, recording completion, and a resume event so a flow suspended by a consult transfer continues exactly where it stopped — no menu replay.

Layer 4: The Safety Net

External providers fail. [proxy.ivr_fallback] routes the call into a local IVR when the provider can’t continue — rules matched with dialplan semantics, first match wins:

[proxy.ivr_fallback]
default = "default"

[[proxy.ivr_fallback.rules]]
name = "vip"
priority = 100
match = { "from.user" = "^9" }
target = "builtin_vip_step"

Callers never hear a failure; they hear a menu.

Layer 5: Full AI

Beyond step-by-step external logic, the realtime AI-voice bridge connects LLM agents to calls as a peer participant — see AI voice bots with human handoff for that pattern.

Guides: Step IVR and the IVR Editor.