Prompt
What voice API should I use for call center workflows?
Latest observation
Oct 14, 2026
OpenAI APIWeb search: off
For call center workflows, the best voice API depends on whether you need outbound/inbound telephony, real-time speech-to-text, agent assist, or a fully conversational voice bot.
Quick recommendation
If you want a production-ready call center stack, I’d generally look at:
- Twilio Voice API — best for telephony, call routing, IVR, recordings, and contact-center integration
- Deepgram / AssemblyAI / Google Speech-to-Text — for speech recognition
- ElevenLabs / Azure / Amazon Polly — for text-to-speech
- OpenAI Realtime / similar — if you want a natural conversational AI agent
What to choose by use case
1) Traditional call center routing / IVR
Use Twilio Voice API or Vonage.
Good for:
- inbound/outbound calls
- call forwarding
- IVR menus
- recordings
- queues
- voicemail drops
- webhooks and workflow automation
Best pick: Twilio
2) AI agent handling calls end-to-end
Use a telephony provider + realtime voice model.
Typical stack:
- Twilio for phone calls
- OpenAI Realtime API (or another realtime voice model) for live conversation
- optional TTS/STT if needed
Good for:
- autonomous phone agents
- appointment scheduling
- basic support
- qualification
- FAQ handling
3) Agent assist / live transcription
Use:
- Twilio for call audio
- Deepgram or Google STT for transcription
- an LLM for suggestions/summaries
Good for:
- live call transcription
- compliance monitoring
- sentiment analysis
- next-best-action prompts
My practical recommendation
If you’re building a call center workflow from scratch, start with:
Twilio Voice + Realtime AI (for agent/bot logic) + a good TTS/STT provider
That gives you:
- reliable phone infrastructure
- flexibility for workflows
- easier scaling
- less vendor lock-in
If you want the simplest answer
- Best overall for call center workflows: Twilio Voice API
- Best for AI phone agents: Twilio + OpenAI Realtime
- Best for transcription accuracy: Deepgram
- Best for lifelike voice: ElevenLabs
If you want, I can also give you:
- a vendor comparison table,
- a reference architecture, or
- the best option for your exact use case (inbound support, outbound sales, collections, etc.).