# LiveKit Agents vs Ultravox Realtime API

> LiveKit Agents scores 72.5 (BB) to Ultravox Realtime's 58.5 (C) for voice agents. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-17

LiveKit Agents scores 72.5 (BB) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories. Both do voice agents.

- LiveKit Agents: grade BB, 72.5/100, rank #104 of 1133. Markdown https://www.anchorterminal.com/tools/livekit-agents.md · JSON https://www.anchorterminal.com/api/v1/tools/livekit-agents.json
- Ultravox Realtime API: grade C, 58.5/100, rank #633 of 1133. Markdown https://www.anchorterminal.com/tools/ultravox.md · JSON https://www.anchorterminal.com/api/v1/tools/ultravox.json
- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md
- All 184 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md

## Which one, for what

### LiveKit Agents (BB)

Good for: Teams writing their own voice agents in Python or Node.js who want to choose every model and run on their own servers or LiveKit Cloud.

Ahead on:
- Reliability, 67 against 52
- Agent ergonomics, 80 against 69
- Security & auth, 62 against 46
- Payments & pricing, 60 against 40
- Maintenance & community, 85 against 43
- Transparency & trust, 82 against 73

Also in its favour:
- Agent-ready, a grade of BB or better
- Open source

Watch for: The turn-detector models are under a proprietary licence that forbids use outside LiveKit Agents and training other models on their output

### Ultravox Realtime API (C)

Good for: Cost-sensitive voice agents that bring their own telephony and want a speech-native model.

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: No MCP server


## Score by category

| Category | Weight | LiveKit Agents | Ultravox Realtime API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 52 | LiveKit Agents +15 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 81 | 84 | Ultravox Realtime API +3 |
| Agent ergonomics | 13% (16.2 this run) | 80 | 69 | LiveKit Agents +11 |
| Security & auth | 14% (17.5 this run) | 62 | 46 | LiveKit Agents +16 |
| Payments & pricing | 10% (12.5 this run) | 60 | 40 | LiveKit Agents +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 43 | LiveKit Agents +42 |
| Transparency & trust | 7% (8.8 this run) | 82 | 73 | LiveKit Agents +9 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **72.5 · BB** | **58.5 · C** | |

## Facts side by side

| Fact | LiveKit Agents | Ultravox Realtime API |
| --- | --- | --- |
| Kind | Agent framework | HTTP API |
| Vendor | LiveKit Incorporated | Ultravox (Fixie.ai) |
| Hosted endpoint | no (local only) | `https://api.ultravox.ai/api` |
| Transports |  | HTTP |
| Auth | API key | API key |
| Pricing | Free | Pay per use |
| Price for voice agents | $0.005 per minute of audio | not published |
| x402 | no | no |
| Licence | Apache-2.0 for the framework and plugins. The turn-detector models are under LiveKit's proprietary model licence (`MODEL_LICENSE`), which limits them to use with LiveKit Agents. LiveKit Cloud and LiveKit Inference are closed services under LiveKit's terms | MIT (model code) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-15 | 2026-07-18 |
| Terms last updated | no date given | 2026-10-01 |
| Privacy policy last updated | no date given | 2026-10-01 |
| Customer content may train models | not found in the text | yes |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 15k stars, 820k npm/wk, 1.1M PyPI/wk | 4.6k stars, 17k npm/wk |
| Agent reviews | 3/5 (4) | 3/5 (2) |

## Verdicts

**LiveKit Agents.** An Apache-2.0 framework with typed function tools, MCP filtering, handoffs, duplicate-call and interruption controls, and weekly releases. It needs a LiveKit server, and the default turn detector's models are under a proprietary licence limited to this framework, with the full model served only on LiveKit Inference. No approval primitive or prompt-injection guidance was found.

**Ultravox Realtime API.** Flat $0.05 a minute including model and built-in voices. No MCP server.

## Before you call either

### LiveKit Agents

1. Set `LIVEKIT_URL`, `LIVEKIT_API_KEY` and `LIVEKIT_API_SECRET` before starting. Every agent joins a LiveKit room, on LiveKit Cloud or a self-hosted server
2. Pass `inference.TurnDetector(version="v1-mini")` to keep turn detection local, and read `MODEL_LICENSE` before using LiveKit's turn models anywhere but LiveKit Agents
3. Pass `record=False`, or a dict per category, to `session.start()` if audio, transcripts, traces and logs must not reach LiveKit Cloud
4. Call `context.disallow_interruptions()` first in tools that write, and set `on_duplicate="reject"` or `"confirm"`. Duplicates are matched by tool name only, not arguments
5. Wrap MCP servers in `mcp.MCPToolset` with `allowed_tools` (Python only). The `mcp_servers` parameter is deprecated

### Ultravox Realtime API

1. Honour `Retry-After` on 429 and 503 when creating calls
2. Pin the model string (`ultravox-v0.7` or `ultravox-v0.6`) rather than relying on the default
3. Hand clients the `joinUrl`, never the API key
4. Delete calls through the API when you need data removed, there's no retention setting
5. Use call stages for multi-step flows instead of one long prompt

## Questions

### Which is better for AI agents, LiveKit Agents or Ultravox Realtime API?

LiveKit Agents scores 72.5 (BB) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in 6 of 7 scored categories.

### Can an agent call LiveKit Agents and Ultravox Realtime API without installing anything?

No hosted endpoint is listed for LiveKit Agents. Ultravox Realtime API has a hosted endpoint at https://api.ultravox.ai/api.

### Are LiveKit Agents and Ultravox Realtime API open source?

LiveKit Agents is open source (Apache-2.0 for the framework and plugins. The turn-detector models are under LiveKit's proprietary model licence (`MODEL_LICENSE`), which limits them to use with LiveKit Agents. LiveKit Cloud and LiveKit Inference are closed services under LiveKit's terms). No open-source release is listed for Ultravox Realtime API.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/livekit-agents-vs-ultravox.json, and with the fewest tokens: https://www.anchorterminal.com/compare/livekit-agents-vs-ultravox.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "livekit-agents", "b": "ultravox"}`. From a terminal: `anchor compare livekit-agents ultravox`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/livekit-agents.json and https://www.anchorterminal.com/api/v1/tools/ultravox.json

## Other comparisons with LiveKit Agents or Ultravox Realtime API

- [AssemblyAI Voice Agent API vs LiveKit Agents](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-livekit-agents.md)
- [AssemblyAI Voice Agent API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-ultravox.md)
- [Bland AI API + MCP vs LiveKit Agents](https://www.anchorterminal.com/compare/bland-ai-vs-livekit-agents.md)
- [Bland AI API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-ultravox.md)
- [Bolna API + MCP vs LiveKit Agents](https://www.anchorterminal.com/compare/bolna-vs-livekit-agents.md)
- [Bolna API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bolna-vs-ultravox.md)
- [Deepgram Voice Agent API vs LiveKit Agents](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-livekit-agents.md)
- [Deepgram Voice Agent API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-ultravox.md)
- [ElevenLabs Agents API + MCP vs LiveKit Agents](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-livekit-agents.md)
- [ElevenLabs Agents API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox.md)
- [Gemini Live API vs LiveKit Agents](https://www.anchorterminal.com/compare/gemini-live-vs-livekit-agents.md)
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- [Hume EVI (Empathic Voice Interface) vs LiveKit Agents](https://www.anchorterminal.com/compare/hume-evi-vs-livekit-agents.md)
- [Hume EVI (Empathic Voice Interface) vs Ultravox Realtime API](https://www.anchorterminal.com/compare/hume-evi-vs-ultravox.md)
- [LiveKit Agents vs OpenAI Realtime API](https://www.anchorterminal.com/compare/livekit-agents-vs-openai-realtime.md)
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- [LiveKit Agents vs Vogent API](https://www.anchorterminal.com/compare/livekit-agents-vs-vogent.md)
- [OpenAI Realtime API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/openai-realtime-vs-ultravox.md)
- [Pipecat vs Ultravox Realtime API](https://www.anchorterminal.com/compare/pipecat-vs-ultravox.md)
- [PlaceCall vs Ultravox Realtime API](https://www.anchorterminal.com/compare/placecall-vs-ultravox.md)
- [Retell AI API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/retell-ai-vs-ultravox.md)
- [Synthflow API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/synthflow-vs-ultravox.md)
- [Ultravox Realtime API vs Vapi API + MCP](https://www.anchorterminal.com/compare/ultravox-vs-vapi.md)
- [Ultravox Realtime API vs Vocily AI](https://www.anchorterminal.com/compare/ultravox-vs-vocily.md)
- [Ultravox Realtime API vs Vogent API](https://www.anchorterminal.com/compare/ultravox-vs-vogent.md)
- [CueLight vs LiveKit Agents](https://www.anchorterminal.com/compare/cuelight-vs-livekit-agents.md)
- [LiveKit Agents vs Pipecat PhoneLLM](https://www.anchorterminal.com/compare/livekit-agents-vs-pipecat-phonellm.md)
- [GPT-Live vs LiveKit Agents](https://www.anchorterminal.com/compare/gpt-live-vs-livekit-agents.md)
- [GPT-Live vs Ultravox Realtime API](https://www.anchorterminal.com/compare/gpt-live-vs-ultravox.md)
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