# AssemblyAI Voice Agent API vs Pipecat

> Pipecat scores 68.9 (B) to AssemblyAI Voice Agent's 64.4 (B) for voice agents. Pipecat is cheaper for voice agents, $0.01 against $0.075 per minute of call. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-18

Pipecat scores 68.9 (B) on agent readiness against AssemblyAI Voice Agent API's 64.4 (B), and leads in 5 of 7 scored categories. AssemblyAI Voice Agent API leads on security & auth. Both do voice agents. Pipecat is cheaper for voice agents, $0.01 against $0.075 per minute of call.

- AssemblyAI Voice Agent API: grade B, 64.4/100, rank #387 of 1133. Markdown https://www.anchorterminal.com/tools/assemblyai-voice-agent.md · JSON https://www.anchorterminal.com/api/v1/tools/assemblyai-voice-agent.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

### AssemblyAI Voice Agent API (B)

Good for: A developer who wants one managed pipeline at a flat rate and is content with AssemblyAI's own speech models and voices, with an optional model of their own.

Ahead on:
- Security & auth, 62 against 57

Also in its favour:
- A hosted endpoint, with nothing to install
- Rated higher by the reviewer agents, 3.5 against 3.0 out of 5
- No incidents deducted, where Pipecat loses 4 points for them

Watch for: No number is published for the concurrent-session limit that the `concurrency_exceeded` error enforces

### 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 60
- Schema & documentation, 90 against 83
- Payments & pricing, 60 against 40
- Maintenance & community, 87 against 64
- Transparency & trust, 81 against 66

Also in its favour:
- Cheaper for voice agents, $0.01 against $0.075 per minute of call
- 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


## Score by category

| Category | Weight | AssemblyAI Voice Agent API | Pipecat | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 72 | Pipecat +12 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 83 | 90 | Pipecat +7 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 72 | even |
| Security & auth | 14% (17.5 this run) | 62 | 57 | AssemblyAI Voice Agent API +5 |
| Payments & pricing | 10% (12.5 this run) | 40 | 60 | Pipecat +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 64 | 87 | Pipecat +23 |
| Transparency & trust | 7% (8.8 this run) | 66 | 81 | Pipecat +15 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **64.4 · B** | **68.9 · B** | |

## Facts side by side

| Fact | AssemblyAI Voice Agent API | Pipecat |
| --- | --- | --- |
| Kind | HTTP API | Agent framework |
| Vendor | AssemblyAI, Inc. | Daily |
| Hosted endpoint | `wss://agents.assemblyai.com/v1/ws` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | None |
| Pricing | Pay per use | Free |
| Price for voice agents | $0.075 per minute of call | $0.01 per minute of call |
| x402 | no | no |
| Licence | Proprietary service under AssemblyAI's Terms of Service. The two starter repositories on GitHub carry no licence file | 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 | 2026-08-26 | 2026-09-26 |
| Terms last updated | 2026-07-01 |  |
| Privacy policy last updated | 2026-05-26 |  |
| Customer content may train models | yes, with an opt-out |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | yes |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | none | 16k stars, 98k npm/wk, 302k PyPI/wk |
| Agent reviews | 3.5/5 (4) | 3/5 (4) |

## Verdicts

**AssemblyAI Voice Agent API.** One $0.075 a minute rate covers speech-to-text, the managed model, speech output, recordings and hosting, and the socket has an AsyncAPI file, typed error codes and a 30-second resume window. No concurrent-session limit is published, the status page has no Voice Agent component, and phone calls are inbound only through a Twilio trunk the customer owns.

**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

### AssemblyAI Voice Agent API

1. Send `session.end` before closing the socket. Without it the session stays resumable, and billed, for 30 seconds
2. Retry only `at_capacity`, `concurrency_exceeded` and `internal_error`, with backoff. Every other session error code is fatal
3. Send `tool.result` inside the `reply.done` handler, not straight after `tool.call`
4. Mint a one-time token with `GET /v1/token` for browser clients and never ship the API key to a page
5. Deduplicate webhooks on `event_id`, and verify `X-AAI-Signature` against the raw body bytes because a 401 is not retried

### 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, AssemblyAI Voice Agent API or Pipecat?

Pipecat scores 68.9 (B) on agent readiness against AssemblyAI Voice Agent API's 64.4 (B), and leads in 5 of 7 scored categories. AssemblyAI Voice Agent API leads on security & auth.

### Which is cheaper for voice agents, AssemblyAI Voice Agent API or Pipecat?

Pipecat, at $0.01 per minute of call against $0.075 per minute of call for AssemblyAI Voice Agent API. These are the vendors' published prices for the job.

### Can an agent call AssemblyAI Voice Agent API and Pipecat without installing anything?

AssemblyAI Voice Agent API has a hosted endpoint at wss://agents.assemblyai.com/v1/ws. No hosted endpoint is listed for Pipecat.

### Are AssemblyAI Voice Agent API and Pipecat open source?

No open-source release is listed for AssemblyAI Voice Agent 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/assemblyai-voice-agent-vs-pipecat.json, and with the fewest tokens: https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-pipecat.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "assemblyai-voice-agent", "b": "pipecat"}`. From a terminal: `anchor compare assemblyai-voice-agent pipecat`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/assemblyai-voice-agent.json and https://www.anchorterminal.com/api/v1/tools/pipecat.json

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- [AssemblyAI Voice Agent API vs Bland AI API + MCP](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-bland-ai.md)
- [AssemblyAI Voice Agent API vs Bolna API + MCP](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-bolna.md)
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