# Alternatives to sipgate flow

> Source: https://theagentsindex.com/sipgate-flow/alternatives/ (re-verified)
> Updated: 24 October 2026

## At a glance

| Name | Best for | Starts at | Better than sipgate flow at | Checked |
| --- | --- | --- | --- | --- |
| [sipgate flow](https://theagentsindex.com/sipgate-flow.md) | — | On quote | — | 26 September 2026 |
| [LiveKit Agents](https://theagentsindex.com/livekit-agents.md) | Engineering teams that want to own their voice-agent stack end to end, self-hosted or on LiveKit Cloud, without being locked into one vendor's API. | Free, then $50/month | Runs autonomously, Multi-agent | 2 September 2026 |
| [OpenAI Realtime API](https://theagentsindex.com/openai-realtime-api.md) | Engineering teams building a voice agent from scratch who want to go directly to OpenAI's own speech-to-speech model (no orchestration platform, no per-minute markup) and are comfortable being single-vendor on OpenAI. | From $10/1m audio input tokens | Multi-agent, Agent permissions | 23 October 2026 |
| [Cartesia](https://theagentsindex.com/cartesia.md) | Engineering teams that want an open-source voice-agent SDK with real LLM choice, built on speech models several rival platforms in this category already license as a component. | Free, then $5/month | Runs autonomously, On the command line | 2 September 2026 |
| [Deepgram Voice Agent API](https://theagentsindex.com/deepgram-voice-agent-api.md) | Engineering teams that want a managed speech pipeline with real LLM-provider choice, and regulated enterprises that need a self-hosted or VPC deployment option a typical closed-source voice-agent vendor does not offer. | From $0.05/minute | Runs autonomously, Open models | 2 September 2026 |

## What to watch for

- **LiveKit Agents**: A framework, not a no-code or dashboard-first builder. Expect to write and deploy real code, unlike this category's more configured rivals.
- **OpenAI Realtime API**: 60-minute maximum session duration.
- **Cartesia**: Line's voice-agent runtime cannot be self-hosted — only the underlying Sonic/Ink models can, on an Enterprise contract.
- **Deepgram Voice Agent API**: No dedicated free tier. A one-time $200 credit only, then usage billing from the first paid session.

The ones people open most here come first, then the closest matches.

## Shortlist

### 1. LiveKit Agents

Open-source Python and Node.js framework for voice AI agents, with LiveKit Cloud hosting, telephony and observability.

**Where it improves on sipgate flow:**
- [Runs autonomously: yes — Agents run as server-side workers dispatched into a live session, handling calls end to end and handing off to a human only when the flow transfers.](https://livekit.com/voice-agents)
- [Multi-agent: yes — Multiple agents in one session via handoffs, plus a supervisor pattern where one agent keeps control and delegates to scoped tasks.](https://docs.livekit.io/agents/logic/workflows.md)
- [Open models: yes — Open-weight models are the recommended default in LiveKit Inference (Gemma 4 31B, GPT OSS 120B, DeepSeek), and the Ollama plugin runs models locally.](https://docs.livekit.io/agents/models/llm/)

**Trade-offs against sipgate flow:**
- [Pooled budget: partial — No per-user balances: allowances pool inside a project. Sharing one plan across projects, and quotas managed at workspace level, are Enterprise only.](https://docs.livekit.io/deploy/admin/quotas-and-limits.md)
- [Data residency: partial — US, EU and India, configurable per project, though the region pinning row on the plan matrix is No for Build and Ship, Yes from Scale. Single-tenant deployments are not offered.](https://livekit.com/security/overview)
- [Certifications: partial — SOC 2 Type II active, GDPR and CCPA/CPRA compliant, EU-US DPF certified; ISO 27001 and PCI DSS still in progress, HIPAA BAAs only for Scale and Enterprise, and the security reports row is Scale and above.](https://livekit.com/security)

[View LiveKit Agents](https://theagentsindex.com/livekit-agents)

### 2. OpenAI Realtime API

Speech-to-speech API for voice agents, with tools, MCP and WebRTC or WebSocket transport.

**Where it improves on sipgate flow:**
- [Multi-agent: yes — Handoffs between agents are a first-class part of a Realtime session, and the vendor points spoken workflows that branch across specialists at its orchestration-and-handoffs guide.](https://developers.openai.com/api/docs/guides/realtime)
- [Agent permissions: yes — Permissioning is explicit and developer-held: function tools exist precisely so approval checks and private system access stay in your application, while MCP tools let the API call a remote server for you.](https://developers.openai.com/api/docs/guides/realtime-mcp)
- [On the command line: partial — The platform ships an official CLI for shell-native workflows, but the documented surfaces it covers are Responses, structured outputs, images, speech and shell work, not realtime sessions.](https://developers.openai.com/api/docs/llms.txt)

**Trade-offs against sipgate flow:**
- [Claude: no — Only OpenAI's own realtime snapshots are supported; the vendor's complete per-endpoint model inventory for /v1/realtime names six gpt-realtime models and no third-party model.](https://developers.openai.com/api/docs/guides/your-data)
- [Open models: no — No open-weight option on this endpoint: the vendor's exhaustive supported-snapshot list for /v1/realtime contains only its own hosted gpt-realtime models.](https://developers.openai.com/api/docs/guides/your-data)
- [Model choice: partial — You choose which realtime snapshot a session uses, including the cheaper mini variants, but the choice is confined to OpenAI's own realtime family; the chained-pipeline alternative is where the vendor offers component swapping.](https://developers.openai.com/api/docs/guides/voice-agents)

[View OpenAI Realtime API](https://theagentsindex.com/openai-realtime-api)

### 3. Cartesia

Real-time speech models and a managed runtime for production phone and web voice agents.

**Where it improves on sipgate flow:**
- [Runs autonomously: yes — A deployed agent runs a whole call unattended, handling turn-taking, interruptions and tool calls; it transfers to a human only when a configured condition matches.](https://docs.cartesia.ai/agents/introduction)
- [On the command line: yes — A `cartesia` CLI creates, deploys and manages agents, and can chat with agent logic locally.](https://docs.cartesia.ai/line/cli)
- [Free tier: yes — A standing $0/mo Free plan, not a trial: it carries 20K credits and $1 of prepaid agent dollars every month, enough for roughly 27 minutes of text to speech, and you sign up without talking to sales. Commercial use licence and voice cloning start at the $5 Pro tier.](https://www.cartesia.ai/pricing)

**Trade-offs against sipgate flow:**
- [Multi-agent: no — System tools enumerate three slots: end call, DTMF, and transfer to an E.164 phone number. An agent therefore hands off to a number, not to another Cartesia agent.](https://docs.cartesia.ai/agents/system-tools)
- [Data residency: partial — By default api.cartesia.ai routes to the nearest endpoint; pinned regional deployments (US, EU, UK, India, Australia) are Enterprise-only.](https://docs.cartesia.ai/enterprise/regional-endpoints)

[View Cartesia](https://theagentsindex.com/cartesia)

### 4. Deepgram Voice Agent API

One WebSocket API that runs speech-to-text, LLM orchestration and text-to-speech for real-time voice agents.

**Where it improves on sipgate flow:**
- [Runs autonomously: yes — The API runs the whole listen-think-speak loop live, handling interruptions and calling functions to take action without a human in the conversation.](https://deepgram.com/product/voice-agent-api)
- [Open models: yes — Open-weight LLMs are listed as supported models: gpt-oss-20b through Groq, which requires you to supply the endpoint, and an NVIDIA Nemotron model that Deepgram manages. Deepgram's own speech and voice weights are not distributed.](https://developers.deepgram.com/docs/voice-agent-llm-models)
- [On the command line: partial — The dg CLI covers transcription, synthesis, text analysis and account management; its own getting-started enumeration and command reference contain no voice-agent command, while the agentic-tools page claims the CLI reaches voice agents. Both statements are recorded in notes.](https://developers.deepgram.com/developer-tools/cli/getting-started)

**Trade-offs against sipgate flow:**
- [Data residency: partial — EU and AU endpoints both serve the agent WebSocket, and Deepgram runs listen and speak in-region; managed LLM traffic is routed in-region only for OpenAI and Google in the EU, and on the AU endpoint the think step is processed outside Australia. Dedicated adds a customer-chosen AWS region.](https://developers.deepgram.com/reference/regional-endpoints)

[View Deepgram Voice Agent API](https://theagentsindex.com/deepgram-voice-agent-api)