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CrazyAI Voice API - outbound AI phone calls, call modes, voicemail detection and pricing

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CrazyAI Voice API - outbound AI phone calls, call modes, voicemail detection and pricing

CrazyAI16 Oct 202621 views
CrazyAICrazyAI Voice APIGrok VoiceHybrid SIP TrunkOutbound CallsVoicemail Detectionpricingsip refer

CrazyAI Voice API - outbound AI phone calls, call modes, voicemail detection and pricing

CrazyAI Voice API lets your AI assistant (Grok Bot, ChatGPT, Claude, or MCP tools), booking system, or CRM place outbound phone calls from your Crazytel PAYG Hybrid SIP Trunk Caller ID, speak in 28 natural voices across 21 languages, transcribe the person's spoken reply to text (callee_transcript), detect voicemail with Crazyswitch AI AMD, and transfer live calls via SIP REFER. There is no monthly subscription fee, and unanswered or busy calls cost $0.00 AUD in AI Voice usage: speaking (Grok Voice TTS) is $0.0285 AUD per 1,000 characters, streaming speech-to-text (grok-voice-transcribe-2.0) is $0.0063 AUD per minute ($0.38 AUD per hour), REST speech-to-text is $0.0032 AUD per minute ($0.19 AUD per hour), Full AI Phone Agent mode (grok-voice-3.0 speech-to-speech) is $0.1520 AUD per minute ($9.12 AUD per hour), and Crazyswitch AI AMD and reply intent check is $0.000181 AUD per 1,000 tokens, plus standard PAYG Hybrid SIP Trunk outbound call rates.

Product page and pricing schedule: https://crazytel.com.au/crazyai-voice-api/#pricing
Portal setup: https://myaccount.crazytel.com.au/crazyai-voice-api/index
OpenAPI reference: https://crazytel.io/docs#/CrazyAI%20Voice%20API

Retail AUD pricing schedule

CrazyAI Voice API has no monthly subscription fee. Connected calls have two transparent charges rated in Australian Dollars (AUD) including GST:

Charge 1: CrazyAI Voice API usage (AUD)

Component AI model / engine Retail rate (AUD) Everyday equivalent
Speaking (Voice Playback / TTS) Grok Voice TTS $0.0285 AUD / 1,000 chars Around half a cent per sentence ($28.50 AUD / 1M chars)
Listening (Streaming Speech-to-Text) grok-voice-transcribe-2.0 $0.0063 AUD / minute $0.38 AUD / hour while listening
Listening (REST Speech-to-Text) grok-voice-transcribe-2.0 $0.0032 AUD / minute $0.19 AUD / hour
Full AI Phone Agent Mode (S2S) grok-voice-3.0 $0.1520 AUD / minute $9.12 AUD / hour ($0.0076 AUD / text input)
Voicemail Tone & Regex Detection Crazyswitch Tone & Regex $0.0000 AUD Free
Crazyswitch AI AMD & Reply Check Crazyswitch AI AMD $0.000181 AUD / 1,000 tokens $0.1809 AUD / 1M tokens
Unanswered / Busy Calls - $0.0000 AUD Free ($0.00 AUD AI Voice usage)

Charge 2: Outbound phone call leg (PAYG Hybrid SIP Trunk)

  • Every outbound call dials out through the Crazytel Hybrid SIP Trunk (hybrid.sip.crazytel.net.au) linked to your Voice Profile using that trunk's verified Australian Caller ID.
  • The outbound phone call leg is billed separately on your Hybrid SIP Trunk's Pay-As-You-Go (PAYG) call rates.
  • PAYG plans only - Because CrazyAI Voice API places automated programmatic outbound calls, linked Hybrid SIP Trunks must be on a PAYG plan. Bundled or included-minute plans cannot be used for automated AI Voice API calls.

How it works in 3 steps

  1. Pick a phone line and voice (once) - In MyAccount > CrazyAI Voice API, select which of your Crazytel PAYG Hybrid SIP Trunks to dial out from (or click New Hybrid Trunk to create one inline using any of your owned Crazytel numbers) and pick one of 28 natural voices. Click Play Sample to preview any voice.
  2. Copy your Profile ID (profile_uuid) - Saving your Voice Profile creates a reusable profile_uuid that stores your phone line, Caller ID, AI voice, voicemail rules, and polite goodbye settings.
  3. Make calls with 2 fields - Send destination and initial_text to POST https://api.crazytel.io/api/v1/crazyai-voice-api/{profile_uuid}/calls with your X-Crazytel-Api-Key header. Crazytel dials the number, speaks your message when answered, listens to the reply, and returns callee_transcript and analysis.callee_reply_intent.

Three call modes

Set your default call mode (default_mode) on the Voice Profile in MyAccount, or override mode on any individual call:

Call mode API value Who drives the call How AI usage is billed Best for
1. Quick Message & Reply (Default) single_turn Crazytel automated turn (1 question, 1 transcribed answer, smart goodbye, hang up) TTS Speaking ($0.0285 / 1k chars) + STT Listening ($0.0063 / min) + optional AI AMD / Intent ($0.000181 / 1k tokens) Appointment confirmations, delivery alerts, quick yes/no checks
2. Back-and-Forth Conversation interactive Your own AI bot controls every turn via /say, /dtmf, /refer, and /hangup while the call stays open (awaiting_next_turn) TTS Speaking ($0.0285 / 1k chars) + STT Listening ($0.0063 / min) per turn Multi-step booking changes, IVR keypad navigation, or calls that need live transfer (/refer) to staff
3. Full AI Phone Agent grok_voice_agent Autonomous grok-voice-3.0 talks back and forth from start to finish using your instructions Full AI Phone Agent S2S ($0.1520 / min; $9.12 / hr) Hands-off conversations where the AI conducts the entire phone call autonomously

Key features

  • Smart answer-dependent goodbyes (closing_message_mode) - In single_turn mode, choose conditional (speaks closing_text_affirmative if they say yes, closing_text_negative if they say no, or closing_text if neutral), static (one standard polite goodbye), wait_for_bot (holds the line open 3 - 60 seconds so your bot can send a custom goodbye to /hangup), or none (immediate hangup).
  • Crazyswitch AI Voicemail Detection (AMD) - Combines free tone and regex checks with Crazyswitch AI AMD classification (conversation, voicemail, no_message, ivr, screener) and automatic voicemail beep detection (440 - 1500 Hz). Actions: leave_voicemail (waits for the greeting and beep to finish, then speaks voicemail_text or default_voicemail_text), terminate (hangs up immediately at $0.00 AUD TTS cost), report_only (returns voicemail_detected so an interactive bot can call /say with wait_for_beep: true), or nothing.
  • Live call transfers to staff (POST .../refer) - Transfer an active call via native Hybrid SIP REFER to internal staff extensions (such as 101), call park slots (700), Australian phone numbers (0290001111), or sip: URIs, with an optional spoken announcement_text and an optional allowed_transfer_targets allowlist. See Hybrid SIP Trunks - hold, transfer, recording, features and pricing.
  • Keypad and IVR navigation (POST .../dtmf) - Send DTMF digits (0-9, *, #, A-D, and , pauses) on an active interactive call and transcribe the next voice prompt.
  • 28 voices, 21 languages, and speech tags - Includes Eve (default), Ara, Rex, Sal, Leo, and 23 more voices across 21 languages (including en and auto). Supports inline tags ([pause], [long-pause], [laugh], [chuckle], [sigh], [breath]) and wrapping tags (<soft>, <whisper>, <slow>, <fast>, <emphasis>).
  • Australian suburb and brand vocabulary - Configure up to 100 custom words in keyterms / extra_keyterms (such as Woolloongabba or Indooroopilly) to improve speech-to-text accuracy, and map phonetic pronunciations in pronunciation_replace (such as Crazytel: Crazy-tel).
  • Safety guardrails and webhooks - Configurable max call duration (default 5 minutes), max ring time, idle session timeout, 5-call account concurrency limit, 5-second duplicate-destination cooldown, and HMAC-SHA256 signed webhooks (X-Crazytel-Signature-256).

REST API endpoints (https://api.crazytel.io)

  • POST /api/v1/crazyai-voice-api/{profile_uuid}/calls - Place an outbound AI Voice call and return callee_transcript, analysis, turns, session, and AUD billing.
  • GET /api/v1/crazyai-voice-api/{profile_uuid}/calls - List call history, transcripts, and AUD billing for profile_uuid.
  • GET /api/v1/crazyai-voice-api/{profile_uuid}/calls/{call_uuid} - Get full call details, turn-by-turn transcript (turns[]), AMD analysis, and AUD billing.
  • POST /api/v1/crazyai-voice-api/{profile_uuid}/calls/{call_uuid}/say - Speak the next turn on an active interactive call or leave a voicemail after the beep (wait_for_beep: true).
  • POST /api/v1/crazyai-voice-api/{profile_uuid}/calls/{call_uuid}/refer - Transfer an active call via Hybrid SIP REFER.
  • POST /api/v1/crazyai-voice-api/{profile_uuid}/calls/{call_uuid}/dtmf - Send DTMF keypad tones and transcribe the next prompt.
  • POST /api/v1/crazyai-voice-api/{profile_uuid}/calls/{call_uuid}/hangup - Speak an optional closing_text and disconnect.
  • GET /api/v1/crazyai-voice-api/profiles and POST /api/v1/crazyai-voice-api/profiles - List or create Voice Profiles.
  • GET /api/v1/crazyai-voice-api/profiles/{profile_uuid}, PUT, and DELETE - Inspect, update, or delete a Voice Profile.
  • GET /api/v1/crazyai-voice-api/voices and POST /api/v1/crazyai-voice-api/voices/preview - List all 28 voices and synthesize a 16 kHz WAV preview clip.
  • GET /api/v1/crazyai-voice-api/pricing - Retrieve live retail AUD pricing.

Compliance and support

Outbound calls display your verified Hybrid SIP Trunk Caller ID (13, 1300, and 1800 inbound-only numbers cannot be used as outbound Caller ID) and include a profile toggle to prepend a call recording disclosure. Any sales or promotional calling must comply with the Do Not Call Register Act 2006 (Cth) and ACMA calling hours.

Need help setting up a Voice Profile or PAYG Hybrid SIP Trunk? Open a ticket in the MyAccount portal helpdesk or call our team on 1800 272 998.

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