Vobiz Voice Xml

Vobiz Voice XML skill

Use this when the user wants to script a call flow declaratively - IVR menus, voicemail, queues, conferences, agent transfers. Anything beyond just "make a call and stream audio" usually involves VobizXML.

How Vobiz fetches XML

1. Call is created via POST /Call/ with answer_url.
2. When the callee answers, Vobiz POSTs to answer_url with call context.
3. Your server returns ...verbs... as application/xml.
4. Verbs execute top-to-bottom.

Core verbs

| Verb | Purpose | |---|---| | ` | TTS - speak text to the caller | | | Play an audio file (HTTPS URL) | | | Collect DTMF or speech input | | | Bridge to another party (PSTN, SIP URI, app, conference) | | | Record the call (optionally stream-while-recording) | | | Open a WebSocket for bidirectional audio (AI voice agents) | | | Add caller to a conference room | | | Fetch new XML from a different URL | | | Pause for N seconds | | | End the call | | ` | Run verbs before answering (no billsec) |

Request payload - what your answer_url receives

Standard application/x-www-form-urlencoded POST (GET sends them as query params). Common parameters: CallUUID, From, To, Direction, CallStatus, HangupCause, Duration, BillDuration, ForwardedFrom, plus ALegUUID/ALegRequestUUID for outbound calls and any custom X-VH- SIP headers. See xml/request for the full list.

Standard callback params by verb

Action/callback URLs receive the standard call params plus verb-specific ones:

• `: InputType (dtmf|speech), Digits, Speech, SpeechConfidenceScore, BilledAmount. Empty Digits/Speech` on timeout.
• `: DialStatus (completed|busy|failed|cancel|timeout|no-answer), DialRingStatus, DialHangupCause, DialALegUUID, DialBLegUUID` (empty if unanswered).
• `: live DialAction` (answer|connected|hangup|digits) events.
• `: RecordUrl, RecordingID, RecordingDuration(Ms), RecordingEndReason` (RecordingTimeout|maxLength|FinishedOnKey|HungUp).
• `: ConferenceAction (enter|exit|start|end), ConferenceUUID, ConferenceName, ConferenceCurrentSize, RecordingUrl` (on end).
• `: standard params + Event=Redirect`.

Per-verb quick recipes

• IVR menu: ` wrapping a ; put fallback +` after it.
• Variable-length input: ``.
• Speech intent: `; threshold SpeechConfidenceScore`.
• Blind transfer: ... then fallback after.
• Screen the agent: ``.
• Voicemail: ` prompt + `.
• Record whole call: `` first.
• Hold music: ... or ``.
• AMD voicemail drop: ` then `.
• Reject without billing: `` as the first element.
• Branch/loop: https://.../next (last runnable element).
• Send tones to a remote IVR: 1WW2#.

Pitfalls

• Response must be application/xml (or text/xml), not text/html/text/plain, served over HTTPS, and under 100 KB. Return within 1-2 s or callers hear dead air.
• **` uses executionTimeout (5-60 s, default 15), NOT timeout.** timeout belongs only to / and is the ring timeout. ` caps total bridged duration - don't confuse the two.
• Verbs execute strictly top-to-bottom. ` and any action-URL handoff (Dial/Gather/Record`) end the current document; elements after them are fallback-only.
• All URLs in `, , , ` (action/callback/confirmSound/dialMusic) must be fully qualified HTTPS.
• DTMF: finishOnKey (default #) is excluded from Digits; set finishOnKey=""/none to rely on numDigits/timeout. On no input, Vobiz still posts with empty Digits/Speech - check for empty.
• Dial: always branch on every DialStatus (busy/no-answer/timeout/failed/cancel/completed). DialBLegUUID is empty when nobody answers.
• Record: timeout is silence timeout (not total length); maxLength is the hard cap. Set maxLength high enough for voicemails.
• Escape &, ` in /` text or the document fails to parse.
• ` defaults to voice="WOMAN", language="en-US"`; not every language has both MAN and WOMAN voices.
• ` early media is unsupported on WebRTC and some PSTN routes - the flow must work without it. Only Speak/Play/Wait` nest inside it.
• loop="0" means infinite (Play, Speak) - it stops only on hangup or a parallel event, never on its own.

When to search docs

• "How do I build an IVR?" → xml/gather, examples/vobiz-ivr-xml-python
• "Voicemail" → xml/record/record-a-voicemail, examples/vobiz-voicemail-xml-python
• "Conference call" → xml/conference, solutions/conference-calling
• "AI voice agent" → xml/stream, integrations/pipecat
• "DTMF input" → xml/dtmf, xml/gather/detecting-speech-inputs

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: vobiz-ai
• Source: vobiz-ai/Agent-Skills
• License: MIT

Install and usage instructions live in the source repository linked above.