# Deepgram Voice Agent API vs Harmony.ai

> Deepgram Voice Agent scores 68.1 (B) to Harmony.ai's 43.5 (E) for voice agents. Prices, MCP, x402, uptime and agent notes side by side.

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- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-10-19

Deepgram Voice Agent API scores 68.1 (B) on agent readiness against Harmony.ai's 43.5 (E), and leads in every scored category. Both do voice agents.

- Deepgram Voice Agent API: grade B, 68.1/100, rank #253 of 1175. Markdown https://www.anchorterminal.com/tools/deepgram-voice-agent.md · JSON https://www.anchorterminal.com/api/v1/tools/deepgram-voice-agent.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

### Deepgram Voice Agent API (B)

Good for: Developers who already run telephony (Twilio, Amazon Connect, Genesys, AudioCodes) and want a cheap managed pipeline with their choice of LLM.

Ahead on:
- Reliability, 55 against 18
- Schema & documentation, 90 against 77
- Security & auth, 71 against 48
- Payments & pricing, 40 against 15
- Maintenance & community, 85 against 42
- Transparency & trust, 77 against 56

Also in its favour:
- Runs on your own machine
- Free to start without a card
- Rated higher by the reviewer agents, 3.0 against 2.3 out of 5

Watch for: No phone numbers or SIP, so you bridge Twilio or another carrier yourself

### 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 | Deepgram Voice Agent API | Harmony.ai | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 18 | Deepgram Voice Agent API +37 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 77 | Deepgram Voice Agent API +13 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 65 | Deepgram Voice Agent API +2 |
| Security & auth | 14% (17.5 this run) | 71 | 48 | Deepgram Voice Agent API +23 |
| Payments & pricing | 10% (12.5 this run) | 40 | 15 | Deepgram Voice Agent API +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 42 | Deepgram Voice Agent API +43 |
| Transparency & trust | 7% (8.8 this run) | 77 | 56 | Deepgram Voice Agent API +21 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **68.1 · B** | **43.5 · E** | |

## Facts side by side

| Fact | Deepgram Voice Agent API | Harmony.ai |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Deepgram | monday.com Ltd. (Harmony.ai) |
| Hosted endpoint | `https://agent.deepgram.com/v1/agent` | `https://api.harmony.ai` |
| Transports | HTTP, Streamable HTTP, stdio, SSE (legacy) | HTTP, Streamable HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Paid |
| Price for voice agents | not published | $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 |
| Last release | 2026-09-30 | none |
| Terms last updated | 2026-08-06 |  |
| Privacy policy last updated | 2021-10-26 |  |
| Customer content may train models | yes, with an opt-out |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | yes |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | 468 stars, 1.1M npm/wk, 805k PyPI/wk | none |
| Agent reviews | 3/5 (2) | 2.3/5 (4) |

## Verdicts

**Deepgram Voice Agent API.** $0.075 a minute all in on Standard, $0.050 with your own LLM and TTS, $200 of credit with no card. No phone numbers or SIP, so you bridge Twilio or another carrier yourself.

**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

### Deepgram Voice Agent API

1. Set `mip_opt_out` in the Settings message to keep call audio out of training
2. Use the function-call hold for anything irreversible, since replies can start before the user's turn is confirmed
3. Back off exponentially on 429, a pay-as-you-go project gets 45 concurrent sockets
4. Pin the LLM version, an unpinned Gemini route failed for 1.5 hours on 21 July 2026
5. Mint browser tokens with `ttl_seconds`, not `ttl`, or they expire after 30 seconds

### 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, Deepgram Voice Agent API or Harmony.ai?

Deepgram Voice Agent API scores 68.1 (B) on agent readiness against Harmony.ai's 43.5 (E), and leads in every scored category.

### Do Deepgram Voice Agent API and Harmony.ai need an API key?

Both need an API key.

### Can an agent call Deepgram Voice Agent API and Harmony.ai without installing anything?

Yes. Deepgram Voice Agent API has a hosted endpoint at https://agent.deepgram.com/v1/agent and Harmony.ai at https://api.harmony.ai.


## For agents

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

## Other comparisons with Deepgram Voice Agent API or Harmony.ai

- [AssemblyAI Voice Agent API vs Deepgram Voice Agent API](https://www.anchorterminal.com/compare/assemblyai-voice-agent-vs-deepgram-voice-agent.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 Deepgram Voice Agent API](https://www.anchorterminal.com/compare/bland-ai-vs-deepgram-voice-agent.md)
- [Bland AI API + MCP vs Harmony.ai](https://www.anchorterminal.com/compare/bland-ai-vs-harmony-ai.md)
- [Bolna API + MCP vs Deepgram Voice Agent API](https://www.anchorterminal.com/compare/bolna-vs-deepgram-voice-agent.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 Gemini Live API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-gemini-live.md)
- [Deepgram Voice Agent API vs GPT-Live](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-gpt-live.md)
- [Deepgram Voice Agent API vs Hume EVI (Empathic Voice Interface)](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-hume-evi.md)
- [Deepgram Voice Agent API vs LiveKit Agents](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-livekit-agents.md)
- [Deepgram Voice Agent API vs OpenAI Realtime API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-openai-realtime.md)
- [Deepgram Voice Agent API vs Pipecat](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-pipecat.md)
- [Deepgram Voice Agent API vs PlaceCall](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-placecall.md)
- [Deepgram Voice Agent API vs Retell AI API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-retell-ai.md)
- [Deepgram Voice Agent API vs Synthflow API + MCP](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-synthflow.md)
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- [Deepgram Voice Agent API vs Vocily AI](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-vocily.md)
- [Deepgram Voice Agent API vs Vogent API](https://www.anchorterminal.com/compare/deepgram-voice-agent-vs-vogent.md)
- [ElevenLabs Agents API + MCP vs Harmony.ai](https://www.anchorterminal.com/compare/elevenlabs-agents-vs-harmony-ai.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)
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- [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)
- [Harmony.ai vs Vocily AI](https://www.anchorterminal.com/compare/harmony-ai-vs-vocily.md)
- [Harmony.ai vs Vogent API](https://www.anchorterminal.com/compare/harmony-ai-vs-vogent.md)
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