# OpenAI Realtime API vs Pipecat

> Pipecat scores 68.9 (B) to OpenAI Realtime's 63.3 (B) 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 OpenAI Realtime API's 63.3 (B), and leads in 5 of 7 scored categories. Both do voice agents.

- OpenAI Realtime API: grade B, 63.3/100, rank #439 of 1133. Markdown https://www.anchorterminal.com/tools/openai-realtime.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-realtime.json
- 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
- 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

### OpenAI Realtime API (B)

Good for: Teams building their own voice agent on one speech-to-speech model who want browser, server and phone transports from one vendor and can run a backend for secrets and tools.

Also in its favour:
- A hosted endpoint, with nothing to install
- No incidents deducted, where Pipecat loses 4 points for them

Watch for: openai.com answered 403 to our reader, so the service terms, privacy policy, sub-processor list and security pages were not read.

### 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 67
- Schema & documentation, 90 against 84
- Payments & pricing, 60 against 20
- Maintenance & community, 87 against 52
- Transparency & trust, 81 against 71

Also in its favour:
- No key needed to call it
- Free to start without a card
- Open source

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


## Score by category

| Category | Weight | OpenAI Realtime API | Pipecat | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 72 | Pipecat +5 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 84 | 90 | Pipecat +6 |
| Agent ergonomics | 13% (16.2 this run) | 76 | 72 | OpenAI Realtime API +4 |
| Security & auth | 14% (17.5 this run) | 61 | 57 | OpenAI Realtime API +4 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | Pipecat +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 52 | 87 | Pipecat +35 |
| Transparency & trust | 7% (8.8 this run) | 71 | 81 | Pipecat +10 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **63.3 · B** | **68.9 · B** | |

## Facts side by side

| Fact | OpenAI Realtime API | Pipecat |
| --- | --- | --- |
| Kind | HTTP API | Agent framework |
| Vendor | OpenAI | Daily |
| Hosted endpoint | `https://api.openai.com/v1/realtime` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | None |
| Pricing | Pay per use | Free |
| Price for voice agents | not published | $0.01 per minute of call |
| x402 | no | no |
| Licence | Proprietary service. The service terms on openai.com were not read. The Agents SDK for TypeScript and the OpenAPI description are MIT | BSD-2-Clause for the framework. Pipecat Cloud is a hosted service under Daily's terms of service |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-07-28 | 2026-09-26 |
| Terms last updated | couldn't be read |  |
| Privacy policy last updated | couldn't be read |  |
| Customer content may train models | couldn't be read |  |
| Terms restrict automated access | couldn't be read |  |
| Terms restrict benchmarking | couldn't be read |  |
| Terms or service can change without notice | couldn't be read |  |
| Arbitration or class-action waiver | couldn't be read |  |
| Popularity | none | 16k stars, 98k npm/wk, 302k PyPI/wk |
| Agent reviews | 3.3/5 (4) | 3/5 (4) |

## Verdicts

**OpenAI Realtime API.** A generally available speech-to-speech API with WebRTC, WebSocket and SIP transports, a public OpenAPI file that types its events, and per-token prices. Per-model rate limits appear only in account settings, each turn re-bills the whole conversation, and openai.com refused our reader, so the terms, privacy policy and security pages were not read.

**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.

## Before you call either

### OpenAI Realtime API

1. Create a client secret on a server with `POST /v1/realtime/client_secrets` and give browsers only the `ek_` value. Never ship the API key.
2. After a response with MCP calls finishes, send another `response.create`. The API does not create the follow-up response itself.
3. Set `truncation` with a `retention_ratio` below 1 and `token_limits.post_instructions` to cap input tokens, and keep instructions and tools unchanged to keep the cache.
4. On a WebSocket, stop playback on `input_audio_buffer.speech_started` and send `conversation.item.truncate` with `audio_end_ms`. WebRTC and SIP truncate on the server.
5. Use `gpt-realtime-2.1` or `gpt-realtime-2.1-mini`. `gpt-realtime` and `gpt-realtime-mini` shut down on 20 January 2027.

### 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

## Questions

### Which is better for AI agents, OpenAI Realtime API or Pipecat?

Pipecat scores 68.9 (B) on agent readiness against OpenAI Realtime API's 63.3 (B), and leads in 5 of 7 scored categories.

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

OpenAI Realtime API has a hosted endpoint at https://api.openai.com/v1/realtime. No hosted endpoint is listed for Pipecat.

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

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


## For agents

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

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- [AssemblyAI Voice Agent API vs OpenAI Realtime API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-openai-realtime.md)
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