# OpenAI Realtime API Review

> OpenAI Realtime API review: Frontier speech-to-speech model API (gpt-realtime family) for low-latency voice agents over WebRTC, WebSocket, and SIP. Verified.

Frontier speech-to-speech model API (gpt-realtime family) for low-latency voice agents over WebRTC, WebSocket, and SIP.

See pricing · facts verified Jul 30, 2026

## What we know about OpenAI Realtime API

OpenAI Realtime API is a voice ai platform: frontier speech-to-speech model API (gpt-realtime family) for low-latency voice agents over WebRTC, WebSocket, and SIP. This profile tracks every OpenAI Realtime API fact we have verified, each linked to a primary source and dated.

OpenAI Realtime API does not publish a public per-minute rate we have been able to verify, so the price figure here stays blank until we can confirm one. We would rather show nothing than a guessed number; if you have a current OpenAI Realtime API quote, it is the fastest way for us to close that gap.

On capabilities, OpenAI Realtime API covers native sip trunking, interruption handling (barge-in), api-first (full lifecycle via api), and self-serve signup, and does not offer llm/tts costs passed through at cost?, annual contract required for best pricing?, and bring-your-own llm. Each of those is verified against OpenAI Realtime API's own docs or dashboard, not marketing copy.

In total we track 10 verified facts for OpenAI Realtime API today, each linking the primary source it came from so you can check our work - and vendor claims we have not measured ourselves are labeled as such on the OpenAI Realtime API fact sheet below.

## Fact sheet

### Pricing

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| LLM/TTS costs passed through at cost? | ✗  No | Jul 30 | [source](https://developers.openai.com/api/docs/pricing) |
| Annual contract required for best pricing? | ✗  No | Jul 30 | [source](https://developers.openai.com/api/docs/pricing) |

### Capabilities

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Native SIP trunking | ✓  Yes | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime-sip) |
| Bring-your-own LLM | ✗  No | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime) |
| Bring-your-own TTS voice | ✗  No | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime-conversations) |
| Buy/port numbers in-platform | ✗  No | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime-sip) |
| Interruption handling (barge-in) | ✓  Yes | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime-conversations) |

### Build experience

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| API-first (full lifecycle via API) | ✓  Yes | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime) |
| Native integrations count (+ key ones: GHL, HubSpot, Zapier, Make, Twilio) | WebRTC, WebSocket, SIP; MCP + tool calling | Jul 30 | [source](https://developers.openai.com/api/docs/guides/realtime) |

### Commercial

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Self-serve signup | ✓  Yes | Jul 30 | [source](https://developers.openai.com/api/docs/pricing) |

## OpenAI Realtime API head-to-head

| Comparison | Record | Per use case |
| --- | --- | --- |
| [OpenAI Realtime API vs Vapi](https://www.versusref.com/voice-ai/openai-realtime-api-vs-vapi/) | won 0 · lost 4 · tied 1 | Custom pipeline control: lost; Ecommerce support and orders: lost; Healthcare compliance: tie; Outbound sales campaigns: lost; SMB receptionist and booking: lost |
| [OpenAI Realtime API vs ElevenLabs Agents](https://www.versusref.com/voice-ai/elevenlabs-agents-vs-openai-realtime-api/) | won 0 · lost 3 · tied 2 | No-code agency deploys: lost; Custom pipeline control: lost; Healthcare compliance: tie; Outbound sales campaigns: tie; SMB receptionist and booking: lost |
| [OpenAI Realtime API vs Google Gemini Live API](https://www.versusref.com/voice-ai/gemini-live-api-vs-openai-realtime-api/) | won 3 · lost 0 · tied 3 | No-code agency deploys: tie; Custom pipeline control: won; Ecommerce support and orders: won; Healthcare compliance: tie; Outbound sales campaigns: won; SMB receptionist and booking: tie |
| [OpenAI Realtime API vs Hume EVI](https://www.versusref.com/voice-ai/hume-evi-vs-openai-realtime-api/) | won 0 · lost 4 · tied 2 | No-code agency deploys: lost; Custom pipeline control: lost; Ecommerce support and orders: tie; Healthcare compliance: lost; Outbound sales campaigns: tie; SMB receptionist and booking: lost |

Source: https://www.versusref.com/voice-ai/tools/openai-realtime-api/