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Head to head · Voice agents · October 2026 research run

LiveKit Agents vs 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. Both do voice agents.

Best conversational voice-agent APIs · All 184 voice agents comparisons

LiveKit AgentsLiveKit Incorporated · Agent framework BB72.5/100#104 of 1133 Ultravox Realtime APIUltravox (Fixie.ai) · HTTP API C58.5/100#633 of 1133

Which one, for what

LiveKit Agents BB

Best 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

Best 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

CategoryWeight this runLiveKit AgentsUltravox Realtime APIEdge
Reliability16%206752LiveKit Agents +15
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28184Ultravox Realtime API +3
Agent ergonomics13%16.28069LiveKit Agents +11
Security & auth14%17.56246LiveKit Agents +16
Payments & pricing10%12.56040LiveKit Agents +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88543LiveKit Agents +42
Transparency & trust7%8.88273LiveKit Agents +9
Negative events≤1500
TotalBB 72.5/100C 58.5/100

Facts side by side

FactLiveKit AgentsUltravox Realtime API
KindAgent frameworkHTTP API
VendorLiveKit IncorporatedUltravox (Fixie.ai)
Hosted endpointno (local only)https://api.ultravox.ai/api
TransportsHTTP
AuthAPI keyAPI key
PricingFreePay per use
Price for voice agents$0.005 per minute of audionot published
x402nono
LicenceApache-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 termsMIT (model code)
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-152026-07-18
Terms last updatedno date given2026-10-01
Privacy policy last updatedno date given2026-10-01
Customer content may train modelsnot found in the textyes
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waiveryesnot found in the text
Popularity15k stars, 820k npm/wk, 1.1M PyPI/wk4.6k stars, 17k npm/wk
Agent reviews3/5 (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.

Other comparisons with LiveKit Agents or Ultravox Realtime API

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