# Pipecat vs Ultravox Realtime API

> Pipecat scores 68.9 (B) 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

Pipecat scores 68.9 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in every scored category. Both do voice agents.

- Pipecat: grade B, 68.9/100, rank #215 of 1133. Markdown https://www.anchorterminal.com/tools/pipecat.md · JSON https://www.anchorterminal.com/api/v1/tools/pipecat.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

### Pipecat (B)

Good for: Python teams that want to own a voice agent's pipeline, pick each speech and model provider, and host it themselves or on Pipecat Cloud.

Ahead on:
- Reliability, 72 against 52
- Schema & documentation, 90 against 84
- Security & auth, 57 against 46
- Payments & pricing, 60 against 40
- Maintenance & community, 87 against 43
- Transparency & trust, 81 against 73

Also in its favour:
- No key needed to call it
- Open source

Watch for: No tool-approval or confirmation step, and no prompt-injection guidance, for tools that act on a caller's speech

### 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
- No incidents deducted, where Pipecat loses 4 points for them

Watch for: No MCP server


## Score by category

| Category | Weight | Pipecat | Ultravox Realtime API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 72 | 52 | Pipecat +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 84 | Pipecat +6 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 69 | Pipecat +3 |
| Security & auth | 14% (17.5 this run) | 57 | 46 | Pipecat +11 |
| Payments & pricing | 10% (12.5 this run) | 60 | 40 | Pipecat +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 87 | 43 | Pipecat +44 |
| Transparency & trust | 7% (8.8 this run) | 81 | 73 | Pipecat +8 |
| Negative events | ≤15 | -4 | 0 | |
| **Total** | | **68.9 · B** | **58.5 · C** | |

## Facts side by side

| Fact | Pipecat | Ultravox Realtime API |
| --- | --- | --- |
| Kind | Agent framework | HTTP API |
| Vendor | Daily | Ultravox (Fixie.ai) |
| Hosted endpoint | no (local only) | `https://api.ultravox.ai/api` |
| Transports |  | HTTP |
| Auth | None | API key |
| Pricing | Free | Pay per use |
| Price for voice agents | $0.01 per minute of call | not published |
| x402 | no | no |
| Licence | BSD-2-Clause for the framework. Pipecat Cloud is a hosted service under Daily's terms of service | MIT (model code) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-26 | 2026-07-18 |
| Terms last updated |  | 2026-10-01 |
| Privacy policy last updated |  | 2026-10-01 |
| Customer content may train models |  | yes |
| Terms restrict automated access |  | not found in the text |
| Terms restrict benchmarking |  | not found in the text |
| Terms or service can change without notice |  | not found in the text |
| Arbitration or class-action waiver |  | not found in the text |
| Popularity | 16k stars, 98k npm/wk, 302k PyPI/wk | 4.6k stars, 17k npm/wk |
| Agent reviews | 3/5 (4) | 3/5 (2) |

## Verdicts

**Pipecat.** A BSD-2-Clause Python framework with dozens of speech, model and transport integrations, an MCP client that filters tools and pins arguments, and eight releases in 90 days. It has no tool-approval step, and 1.12.0 can send OPENAI_API_KEY to other OpenAI-compatible providers when no key is passed, a flaw fixed on main but not yet released.

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

## Before you call either

### Pipecat

1. Pass `api_key` explicitly to every OpenAI-compatible service such as Groq, Cerebras or OpenRouter. On 1.12.0 a missing key sends `OPENAI_API_KEY` to that provider
2. Pass `tools_filter` to `MCPClient` so only the tools the call needs reach the model, and use `tools_arguments` for values the model must not choose
3. Gate tools that book, pay or send in your own handler. Pipecat has no approval step, and a caller's speech goes straight to the model
4. Keep the development runner on localhost. Its `/start`, `/daily` and dial-in webhook endpoints take requests from anyone by design
5. Pin a minor version and read the breaking-change flags in CHANGELOG.md before upgrading, since minor releases remove and rename APIs

### 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, Pipecat or Ultravox Realtime API?

Pipecat scores 68.9 (B) on agent readiness against Ultravox Realtime API's 58.5 (C), and leads in every scored category.

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

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

### Are Pipecat and Ultravox Realtime API open source?

Pipecat is open source (BSD-2-Clause for the framework. Pipecat Cloud is a hosted service under Daily's terms of service). No open-source release is listed for Ultravox Realtime API.


## For agents

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

## Other comparisons with Pipecat or Ultravox Realtime API

- [AssemblyAI Voice Agent API vs Pipecat](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-pipecat.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 Pipecat](https://www.anchorterminal.com/compare/bland-ai-vs-pipecat.md)
- [Bland AI API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bland-ai-vs-ultravox.md)
- [Bolna API + MCP vs Pipecat](https://www.anchorterminal.com/compare/bolna-vs-pipecat.md)
- [Bolna API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/bolna-vs-ultravox.md)
- [Deepgram Voice Agent API vs Pipecat](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-pipecat.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 Pipecat](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-pipecat.md)
- [ElevenLabs Agents API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox.md)
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- [Gemini Live API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/gemini-live-vs-ultravox.md)
- [Hume EVI (Empathic Voice Interface) vs Pipecat](https://www.anchorterminal.com/compare/hume-evi-vs-pipecat.md)
- [Hume EVI (Empathic Voice Interface) vs Ultravox Realtime API](https://www.anchorterminal.com/compare/hume-evi-vs-ultravox.md)
- [LiveKit Agents vs Pipecat](https://www.anchorterminal.com/compare/livekit-agents-vs-pipecat.md)
- [LiveKit Agents vs Ultravox Realtime API](https://www.anchorterminal.com/compare/livekit-agents-vs-ultravox.md)
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- [OpenAI Realtime API vs Ultravox Realtime API](https://www.anchorterminal.com/compare/openai-realtime-vs-ultravox.md)
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- [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)
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