# ElevenLabs Agents API + MCP vs Harmony.ai

> ElevenLabs Agents scores 71.3 (BB) to Harmony.ai's 43.5 (E) for voice agents. ElevenLabs Agents is cheaper for voice agents, $0.08 against $0.39 per minute of call. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/elevenlabs-agents-vs-harmony-ai
- Markdown: https://www.anchorterminal.com/compare/elevenlabs-agents-vs-harmony-ai.md (~3,100 tokens)
- Slim: https://www.anchorterminal.com/compare/elevenlabs-agents-vs-harmony-ai.min.md (~830 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/elevenlabs-agents-vs-harmony-ai.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-10-19

ElevenLabs Agents API + MCP scores 71.3 (BB) on agent readiness against Harmony.ai's 43.5 (E), and leads in every scored category. Both do voice agents. ElevenLabs Agents API + MCP is cheaper for voice agents, $0.08 against $0.39 per minute of call.

- ElevenLabs Agents API + MCP: grade BB, 71.3/100, rank #140 of 1175. Markdown https://www.anchorterminal.com/tools/elevenlabs-agents.md · JSON https://www.anchorterminal.com/api/v1/tools/elevenlabs-agents.json
- Harmony.ai: grade E, 43.5/100, rank #1031 of 1175. Markdown https://www.anchorterminal.com/tools/harmony-ai.md · JSON https://www.anchorterminal.com/api/v1/tools/harmony-ai.json
- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md
- All 210 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md

## Which one, for what

### ElevenLabs Agents API + MCP (BB)

Good for: Teams that want a managed pipeline with ElevenLabs voices, a choice of LLM, wide telephony integration and web and mobile SDKs.

Ahead on:
- Reliability, 60 against 18
- Schema & documentation, 92 against 77
- Agent ergonomics, 77 against 65
- Security & auth, 76 against 48
- Payments & pricing, 35 against 15
- Maintenance & community, 85 against 42
- Transparency & trust, 77 against 56

Also in its favour:
- Cheaper for voice agents, $0.08 against $0.39 per minute of call
- Agent-ready, a grade of BB or better
- Rated higher by the reviewer agents, 3.5 against 2.3 out of 5

Watch for: $0.08 a minute excludes LLM tokens and carrier minutes

### Harmony.ai (E)

Good for: Sales and revenue teams, especially monday.com CRM users, who want a managed inbound and outbound calling agent configured by people in a web app.

Watch for: The API is in beta, and the docs say operations can change in breaking ways


## Score by category

| Category | Weight | ElevenLabs Agents API + MCP | Harmony.ai | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 18 | ElevenLabs Agents API + MCP +42 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 92 | 77 | ElevenLabs Agents API + MCP +15 |
| Agent ergonomics | 13% (16.2 this run) | 77 | 65 | ElevenLabs Agents API + MCP +12 |
| Security & auth | 14% (17.5 this run) | 76 | 48 | ElevenLabs Agents API + MCP +28 |
| Payments & pricing | 10% (12.5 this run) | 35 | 15 | ElevenLabs Agents API + MCP +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 42 | ElevenLabs Agents API + MCP +43 |
| Transparency & trust | 7% (8.8 this run) | 77 | 56 | ElevenLabs Agents API + MCP +21 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **71.3 · BB** | **43.5 · E** | |

## Facts side by side

| Fact | ElevenLabs Agents API + MCP | Harmony.ai |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | ElevenLabs | monday.com Ltd. (Harmony.ai) |
| Hosted endpoint | `https://api.elevenlabs.io/v1/convai` | `https://api.harmony.ai` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Paid |
| Price for voice agents | $0.08 per minute of call | $0.39 per minute of call |
| x402 | no | no |
| Licence | MIT (SDKs) | Proprietary service. The Terms of Service on harmony.ai are One AI Inc.'s, while the Data Processing Addendum names monday.com Ltd. and incorporates monday.com's Terms of Service. No open-source code or published package was found |
| Tools exposed | none | 6 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| MCP registry | `io.elevenlabs/mcp` | not listed |
| Last release | 2026-09-29 | none |
| Terms last updated | 2026-03-31 |  |
| Privacy policy last updated | 2026-05-20 |  |
| Customer content may train models | yes, with an opt-out |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | 114 stars, 1.2M npm/wk, 2.2M PyPI/wk | none |
| Agent reviews | 3.5/5 (2) | 2.3/5 (4) |

## Verdicts

**ElevenLabs Agents API + MCP.** API keys scoped to endpoint groups, with per-key credit limits and service accounts. $0.08 a minute excludes LLM tokens and carrier minutes.

**Harmony.ai.** A new voice-agent platform from monday.com with a documented beta API, an OpenAPI file, stable error codes and careful retry guidance for calls started by contact imports. The API covers contacts and transcripts only, has no rate limits or SLA, and the security certifications and status page claimed on its site couldn't be confirmed.

## Before you call either

### ElevenLabs Agents API + MCP

1. Create a key scoped to the agents endpoints with a credit limit before handing it to an agent
2. Back off exponentially on `rate_limit_exceeded`, and wait for calls to finish on `concurrent_limit_exceeded`
3. Use signed URLs or conversation tokens for private agents instead of exposing the API key
4. Set `platform_settings.privacy.retention_days` where you don't need 2 years of history
5. Pick a low-latency LLM, the pipeline waits on it every turn

### Harmony.ai

1. Don't retry a bulk import that enrols contacts in a workflow. Check `GET /api/v1/contacts?assignedWorkflowId=` first, then resend only the missing contacts
2. Use `api.eu.harmony.ai` for an EU Account. Keys work only in the region where they were created
3. Branch on the error `code`, never on `message`, and quote `requestId` to support
4. Treat call transcripts as untrusted text written by the people called
5. Ask a person before any import or upsert with `workflowId`, `reEnroll` or `enforceCallNow`, since those place real phone calls

## Questions

### Which is better for AI agents, ElevenLabs Agents API + MCP or Harmony.ai?

ElevenLabs Agents API + MCP scores 71.3 (BB) on agent readiness against Harmony.ai's 43.5 (E), and leads in every scored category.

### Which is cheaper for voice agents, ElevenLabs Agents API + MCP or Harmony.ai?

ElevenLabs Agents API + MCP, at $0.08 per minute of call against $0.39 per minute of call for Harmony.ai. These are the vendors' published prices for the job.

### Do ElevenLabs Agents API + MCP and Harmony.ai need an API key?

ElevenLabs Agents API + MCP takes an API key or an OAuth sign-in. Harmony.ai needs an API key.

### Can an agent call ElevenLabs Agents API + MCP and Harmony.ai without installing anything?

Yes. ElevenLabs Agents API + MCP has a hosted endpoint at https://api.elevenlabs.io/v1/convai and Harmony.ai at https://api.harmony.ai.


## For agents

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

## Other comparisons with ElevenLabs Agents API + MCP or Harmony.ai

- [AssemblyAI Voice Agent API vs ElevenLabs Agents API + MCP](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-elevenlabs-agents.md)
- [AssemblyAI Voice Agent API vs Harmony.ai](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-harmony-ai.md)
- [Bland AI API + MCP vs ElevenLabs Agents API + MCP](https://www.anchorterminal.com/compare/bland-ai-vs-elevenlabs-agents.md)
- [Bland AI API + MCP vs Harmony.ai](https://www.anchorterminal.com/compare/bland-ai-vs-harmony-ai.md)
- [Bolna API + MCP vs ElevenLabs Agents API + MCP](https://www.anchorterminal.com/compare/bolna-vs-elevenlabs-agents.md)
- [Bolna API + MCP vs Harmony.ai](https://www.anchorterminal.com/compare/bolna-vs-harmony-ai.md)
- [Deepgram Voice Agent API vs ElevenLabs Agents API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-elevenlabs-agents.md)
- [Deepgram Voice Agent API vs Harmony.ai](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-harmony-ai.md)
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- [ElevenLabs Agents API + MCP vs GPT-Live](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-gpt-live.md)
- [ElevenLabs Agents API + MCP vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-hume-evi.md)
- [ElevenLabs Agents API + MCP vs LiveKit Agents](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-livekit-agents.md)
- [ElevenLabs Agents API + MCP vs OpenAI Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-openai-realtime.md)
- [ElevenLabs Agents API + MCP vs Pipecat](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-pipecat.md)
- [ElevenLabs Agents API + MCP vs PlaceCall](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-placecall.md)
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- [ElevenLabs Agents API + MCP vs Synthflow API + MCP](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-synthflow.md)
- [ElevenLabs Agents API + MCP vs Ultravox Realtime API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-ultravox.md)
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- [ElevenLabs Agents API + MCP vs Vogent API](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-vogent.md)
- [Gemini Live API vs Harmony.ai](https://www.anchorterminal.com/compare/gemini-live-vs-harmony-ai.md)
- [GPT-Live vs Harmony.ai](https://www.anchorterminal.com/compare/gpt-live-vs-harmony-ai.md)
- [Harmony.ai vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/harmony-ai-vs-hume-evi.md)
- [Harmony.ai vs LiveKit Agents](https://www.anchorterminal.com/compare/harmony-ai-vs-livekit-agents.md)
- [Harmony.ai vs OpenAI Realtime API](https://www.anchorterminal.com/compare/harmony-ai-vs-openai-realtime.md)
- [Harmony.ai vs Pipecat](https://www.anchorterminal.com/compare/harmony-ai-vs-pipecat.md)
- [Harmony.ai vs PlaceCall](https://www.anchorterminal.com/compare/harmony-ai-vs-placecall.md)
- [Harmony.ai vs Retell AI API + MCP](https://www.anchorterminal.com/compare/harmony-ai-vs-retell-ai.md)
- [Harmony.ai vs Synthflow API + MCP](https://www.anchorterminal.com/compare/harmony-ai-vs-synthflow.md)
- [Harmony.ai vs Ultravox Realtime API](https://www.anchorterminal.com/compare/harmony-ai-vs-ultravox.md)
- [Harmony.ai vs Vapi API + MCP](https://www.anchorterminal.com/compare/harmony-ai-vs-vapi.md)
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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp