Cloud Providers for Real-Time Audio Streaming to LLM Apps
The short answer
For a voice or audio app that talks to an LLM, pick the transport by where the audio comes from, then pick the model by latency. As of October 20, 2026:
- LiveKit Cloud — the default for web and mobile voice agents: WebRTC rooms, hosted agent workers, SIP telephony and LiveKit Inference (STT, LLM, TTS behind one key) in one bill. $0.01 per agent-session minute after the plan allowance.
- Pipecat Cloud (Daily) — the best fit if you already write agents in the open-source Pipecat framework: $0.01 per active minute (agent-1x), Daily WebRTC voice transport free for 1:1 sessions, PSTN dial-in $0.018 a minute.
- Twilio ConversationRelay — the shortest path for phone calls: Twilio handles the call, speech recognition and synthesis and streams text to your LLM over a WebSocket. $0.07 a minute plus standard Twilio voice minutes.
- Cloudflare Realtime — the cheapest raw transport at scale: an anycast SFU and TURN at $0.05 per GB of egress with 1,000 GB a month free, plus a WebSocket adapter to bridge audio to your backend. You build the agent layer yourself.
The transport is rarely what blows a 300 ms budget. Speech recognition, the model’s time to first token and speech synthesis are. This page covers the transport and hosting layer; for the models themselves see Grok Voice 3.0 vs GPT-Live-1 vs Gemini 3.8 Live, and for fast text inference see best AI infrastructure providers for real-time inference.
The comparison
Prices are from each vendor’s pricing page on October 20, 2026.
| Provider | Audio enters via | Agent hosting | Platform price | Model costs | Best for |
|---|---|---|---|---|---|
| LiveKit Cloud | WebRTC, SIP, phone numbers | Yes (Python/Node agents, 1-second metering, 10-second minimum) | Build $0 (1,000 agent min) · Ship $50/mo (5,000) · Scale $500/mo (50,000) · then $0.01/min | LiveKit Inference credits ($2.50 / $5 / $50 included) or bring your own keys | Web and mobile voice agents, one vendor for media + agents |
| Pipecat Cloud (Daily) | Daily WebRTC, SIP $0.003–$0.02/min, PSTN $0.018/min, Twilio, WebSocket | Yes (containers: agent-1x/2x/3x) | $0.01 / $0.02 / $0.03 per active min; reserved warm instances $0.0005/min (1x) | Bring your own (80+ STT, LLM, TTS providers) | Teams on the open-source Pipecat framework |
| Twilio ConversationRelay | PSTN and SIP calls | No — your LLM app runs elsewhere and receives text over WebSocket | $0.07/min + Twilio voice minutes | Your LLM; STT/TTS handled by the relay | Phone agents on an existing Twilio estate |
| Cloudflare Realtime | WebRTC SFU, TURN, WebSocket adapter | No (Workers, Durable Objects and Containers billed separately) | $0.05/GB egress; first 1,000 GB/mo free; ingress free | Workers AI or any API | High-volume, build-it-yourself audio transport |
Where the 300 milliseconds go
Measure from the moment the user stops speaking to the first byte of the agent’s audio. In a cascaded pipeline, that interval is the sum of:
- End-of-turn detection — deciding the user has finished. LiveKit includes its turn-detection model free for agents hosted on its cloud; Pipecat Cloud includes Krisp VIVA noise and voice isolation free up to 10,000 active minutes a month.
- Final speech-to-text result — streaming STT returns partial transcripts as the user talks, so only the last fragment is on the critical path.
- LLM time to first token — usually the largest single item. Small, fast models and prompt caching matter more than the transport.
- Text-to-speech time to first audio — streaming TTS starts speaking before the sentence is complete.
- Network — two legs, user to edge and edge to model. Keep the agent worker, the model endpoint and the user in the same region.
A speech-to-speech model collapses steps 2–4 into one: GPT-Live-1 is $0.05 a minute, Grok Voice 3.0 $0.08 a minute, and Gemini 3.8 Live bills audio at about $0.005 a minute in and $0.018 out (prices from our voice API price table, verified October 17, 2026). All four providers above can carry either architecture.
Picks by job
- A voice assistant in a web or mobile app: LiveKit Cloud. Media, agent hosting, telephony and observability in one place; the free Build plan covers 1,000 agent minutes to prototype.
- You already have a Pipecat agent: Pipecat Cloud. Same code, managed scaling, and free 1:1 WebRTC voice transport.
- Inbound or outbound phone calls on Twilio: ConversationRelay if you want Twilio to own speech recognition and synthesis; Twilio Media Streams into LiveKit or Pipecat if you want to choose your own STT and TTS.
- Millions of minutes and an in-house media team: Cloudflare Realtime for transport, your own agent workers next to your model provider.
- A no-code phone agent instead of a platform: see Retell vs Vapi vs Bland.
How to test a provider in an afternoon
- Deploy the provider’s starter agent in the region nearest your users and your model.
- Log four timestamps per turn: end of user speech, final transcript, first LLM token, first audio byte out.
- Run 100 turns from a real phone and a real mobile network, not only from a laptop on office Wi-Fi, and compare the 95th percentile, not the average.
- Price one minute end to end: platform minute + telephony + STT + LLM + TTS. LiveKit’s calculator showed about $0.048 a minute for a sample web stack on October 20, 2026.
Last verified: October 20, 2026.