# OpenAI Realtime API Alternatives (2026): 5 Compared

> Source: https://theagentsindex.com/openai-realtime-api/alternatives (curated, quality-gated, re-verified)

OpenAI Realtime API's real strength is being a raw model API and nothing more: WebRTC for browser and mobile clients, WebSocket for server-side pipelines, native SIP for telephony, all billed purely on audio and text tokens with no platform fee layered on top -- genuinely the leanest way to get speech-to-speech if you are willing to build the application logic around it yourself. That leanness is also what a switcher is usually reacting to: there is no built-in call-flow orchestration, no turn-management or tool-calling scaffolding, and no telephony provider integration beyond raw SIP -- you manage the conversation lifecycle in your own code, and you are using OpenAI's own models exclusively. None of that makes OpenAI Realtime API wrong -- if you want the cheapest, most transparent per-token bill and are building your own orchestration layer anyway, that is exactly the job it does. Stay with OpenAI Realtime API if you want a pure model API with transparent per-token billing and are comfortable building the call-orchestration layer yourself. Move if you want that orchestration layer built for you, provider flexibility instead of being locked to OpenAI's own models, compliance-grade deployment options, a phone-telephony specialist with SIP trunking handled, or voice quality and cloning decoupled from model choice entirely. The five tools below are independently researched, Published listings on this site: each carries current positioning and pricing we verified directly against the vendor, and an honest best-for call.

| # | Name | What it is | Why it's here | Pricing | API |
| --- | --- | --- | --- | --- | --- |
| 1 | [LiveKit Agents](https://theagentsindex.com/livekit-agents.md) | The Apache 2.0 voice-agent framework. 13.1k GitHub stars, self-hostable, and the only open-source pick in this category with fully published pricing. | For the reader who wants provider flexibility and self-hosted control instead of being locked to OpenAI's own models. LiveKit's own site confirms the Agents SDK is open source (Apache 2.0), self-hostable, and provider-agnostic -- swap STT, LLM and TTS providers through a plugin system without rewriting agent logic -- and is the infrastructure behind ChatGPT's own Advanced Voice Mode. Component pricing runs roughly $0.05-$0.30/minute at scale depending on providers chosen. The tradeoff: you assemble and operate the pipeline yourself, there is no single managed bill. | $0 / month | Yes |
| 2 | [Vapi](https://theagentsindex.com/vapi.md) | The developer platform for voice AI agents, bring your own model, voice and telephony, and Vapi orchestrates the call. | For the reader who wants the call-orchestration layer built for them instead of hand-rolling it against a raw model API. Vapi's own site confirms a unified platform for voice, conversation flow, telephony and integrations, with its own pricing page confirming a Build plan at $0.05/minute (60+ minutes included, model costs passed through at provider rates, $10/month per additional concurrent line) and an annual Scale plan for volume. The tradeoff: a per-minute platform fee on top of model costs, versus OpenAI's raw audio-token-only billing. | $0.05 / min | Yes |
| 3 | [Deepgram Voice Agent API](https://theagentsindex.com/deepgram-voice-agent-api.md) | The speech-infrastructure vendor's own voice-agent API. Managed STT, LLM and TTS over a single WebSocket, $4.50/hr flat, with 6 LLM providers and self-hosted or VPC deployment on the same product. | For the reader who wants multi-provider flexibility with compliance-grade deployment options. Deepgram's own site confirms bring-your-own-LLM or TTS while keeping Deepgram's orchestration and streaming pipeline, deployable fully managed, single-tenant, in VPC, or fully self-hosted for HIPAA, GDPR and data-residency needs, at a flat $4.50/hour with the full stack. The tradeoff: a flat hourly rate rather than OpenAI's pure per-token metering. | $4.50/hr Standard / Standard to Custom (BYO LLM and TTS) | Yes |
| 4 | [Retell AI](https://theagentsindex.com/retell-ai.md) | Build phone-call voice agents on Retell's turn-taking layer, plug in your own LLM, voice, and telephony, ship over voice, chat, or SMS. | For the reader who wants a phone-telephony specialist instead of raw SIP. Retell's own site confirms SIP trunking to any telephony provider (Twilio, Vonage, or existing numbers), with its own pricing page confirming pay-as-you-go billing, $10 in free credit, $0.07-$0.31/minute for voice agents, and 20 free concurrent calls. The tradeoff: a real per-minute premium over OpenAI's raw audio-token rate, since call orchestration and telephony are bundled in. | $0.07–$0.31 / min | Yes |
| 5 | [ElevenLabs Conversational AI](https://theagentsindex.com/elevenlabs-conversational-ai.md) | The voice-quality specialist’s own agent layer, 10,000+ voices and instant cloning, with a bring-your-own-LLM brain. | For the reader whose actual constraint is voice quality and cloning, not the model. ElevenLabs' own documentation confirms bring-your-own-LLM across OpenAI, Anthropic, Google Gemini or a custom endpoint, plus 10,000+ voices with instant cloning. The tradeoff: no public self-serve pricing to compare against OpenAI's transparent per-token rate -- ElevenLabs is sales-led. | $0 / mo | Yes |

## Methodology

We only draw alternatives from this site's own Published, individually-researched listings, never a fresh, unverified list. OpenAI Realtime API's own 10-listing voice agent category was checked for genuinely distinct switching reasons rather than named on volume: the five below were picked specifically because each answers a different documented reason a reader leaves OpenAI Realtime API -- wanting the orchestration layer built in, provider flexibility instead of OpenAI-only models, compliance-grade deployment options, phone-telephony handled for you, or voice quality and cloning as the deciding factor. Every price and platform claim below was checked live against the vendor's own site on 2026-08-20.