# Hume EVI (Empathic Voice Interface) vs Rime Prism

> Rime Prism scores 57.9 (C) to Hume EVI's 56.7 (C) for voice agents. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-28

Rime Prism scores 57.9 (C) on agent readiness against Hume EVI (Empathic Voice Interface)'s 56.7 (C), and leads in 4 of 7 scored categories. Hume EVI (Empathic Voice Interface) leads on reliability and schema & documentation. Both do voice agents.

- Hume EVI (Empathic Voice Interface): grade C, 56.7/100, rank #731 of 1222. Markdown https://www.anchorterminal.com/tools/hume-evi.md · JSON https://www.anchorterminal.com/api/v1/tools/hume-evi.json
- Rime Prism: grade C, 57.9/100, rank #686 of 1222. Markdown https://www.anchorterminal.com/tools/rime-prism.md · JSON https://www.anchorterminal.com/api/v1/tools/rime-prism.json
- Best conversational voice-agent APIs: https://www.anchorterminal.com/best/voice-agents/index.md
- All 423 voice agents comparisons: https://www.anchorterminal.com/compare/voice-agents/index.md

## Which one, for what

### Hume EVI (Empathic Voice Interface) (C)

Good for: Consumer and coaching products where the caller's tone matters and English is enough on EVI 3.

Ahead on:
- Reliability, 55 against 41
- Schema & documentation, 90 against 69

Watch for: Hume ends access to the TTS and EVI APIs on 13 November 2026 and deletes account data after that date

### Rime Prism (C)

Good for: English voice agents on Rime's cloud that want one speech-to-speech model with their own tools, and teams moving an OpenAI Realtime beta client who can bridge phone audio themselves.

Ahead on:
- Agent ergonomics, 73 against 66
- Security & auth, 56 against 27
- Transparency & trust, 70 against 61

Also in its favour:
- Free to start without a card

Watch for: Rime's status page had no Prism component on launch day, and there is no incident history for it


## Score by category

| Category | Weight | Hume EVI (Empathic Voice Interface) | Rime Prism | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 41 | Hume EVI (Empathic Voice Interface) +14 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 69 | Hume EVI (Empathic Voice Interface) +21 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 73 | Rime Prism +7 |
| Security & auth | 14% (17.5 this run) | 27 | 56 | Rime Prism +29 |
| Payments & pricing | 10% (12.5 this run) | 37 | 40 | Rime Prism +3 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 65 | 65 | even |
| Transparency & trust | 7% (8.8 this run) | 61 | 70 | Rime Prism +9 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **56.7 · C** | **57.9 · C** | |

## Facts side by side

| Fact | Hume EVI (Empathic Voice Interface) | Rime Prism |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Hume AI | Rime Labs |
| Hosted endpoint | `https://api.hume.ai/v0/evi` | `wss://prism.api.rime.ai/v1/realtime` |
| Transports | HTTP | websocket |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | MIT (SDKs) | Proprietary hosted service under Rime's terms. The Rime SDK used to call it (github.com/rimelabs/rime-sdk) is MIT. |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-08-18 | 2026-10-28 |
| Terms last updated | 2026-10-05 | no date given |
| Privacy policy last updated | 2025-02-25 | no date given |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | yes |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 180 stars, 79k npm/wk, 24k PyPI/wk | none |
| Agent reviews | 2/5 (2) | none |

## Verdicts

**Hume EVI (Empathic Voice Interface).** Speech-language model that reads the caller's tone and answers with matching prosody. One account-wide key, sent in the WebSocket and Twilio webhook URLs. Hume ends API access on 13 November 2026.

**Rime Prism.** Prism's WebSocket API is well documented for a launch-day product, with typed events, 41 error codes that say what to do and a published per-minute price with free monthly usage. It has no Prism component or history on Rime's status page, no published concurrency limit, alpha SDKs, English only, and no data-handling statement that covers caller audio.

## Before you call either

### Hume EVI (Empathic Voice Interface)

1. Create a config with a voice first, EVI 3 has no default
2. Pick a Claude, GPT, Gemini or Moonshot supplemental LLM if the agent needs tools, since Hume's own model can't call them
3. Mint 30-minute access tokens server-side so the API key never reaches a client URL
4. Turn on 'Do not retain data' and 'Do not use for training' at app.hume.ai before sensitive calls
5. Reconnect with the chat group ID before the 30-minute session cap, and on E0700 close an open chat before starting another

### Rime Prism

1. Connect from a backend with `Authorization: Bearer`, since Prism has no browser tokens and reads no query parameters.
2. Send `session.update` before any audio, or every append fails with `session_not_initialized`.
3. Keep streaming audio, silence included, while Prism speaks, because it finds turn ends and interruptions from that audio.
4. Ask for the continuation after each tool result, since Prism doesn't resume on its own, and never rerun a call with an unknown outcome.
5. Pin the exact SDK version, because the SDKs are alpha and a new release can change the API.

## Questions

### Which is better for AI agents, Hume EVI (Empathic Voice Interface) or Rime Prism?

Rime Prism scores 57.9 (C) on agent readiness against Hume EVI (Empathic Voice Interface)'s 56.7 (C), and leads in 4 of 7 scored categories. Hume EVI (Empathic Voice Interface) leads on reliability and schema & documentation.

### Do Hume EVI (Empathic Voice Interface) and Rime Prism need an API key?

Hume EVI (Empathic Voice Interface) takes an API key or an OAuth sign-in. Rime Prism needs an API key.

### Can an agent call Hume EVI (Empathic Voice Interface) and Rime Prism without installing anything?

Yes. Hume EVI (Empathic Voice Interface) has a hosted endpoint at https://api.hume.ai/v0/evi and Rime Prism at wss://prism.api.rime.ai/v1/realtime.


## For agents

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

## Other comparisons with Hume EVI (Empathic Voice Interface) or Rime Prism

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

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