Hume EVI
https://www.hume.ai/products/empathic-voice-interface
Hume's Empathic Voice Interface (EVI) — voice agent platform with vocal-affect understanding. Hume raised $50M Series B Mar-2024 (EQT). Distinguished from pure LLM voice agents by emotion/prosody modelling; uses Hume's proprietary speech-prosody models.
At a glance
- Type
- Empathic voice-AI platform (voice + emotion)
- Tier
- T1
- Section
- Voice agent platforms
- Created
- 2024 (EVI launched; Hume founded 2021)
- Latest release
- EVI 2 (2024-09)
- License
- not applicable — not OSS
- GitHub
- github.com/HumeAI (SDKs)
- Pricing
- Per-minute usage; tiered + Enterprise
- Funding
- $50M Series B Mar-2024 (EQT)
Taxonomy
- storage
- kv
- retrieval
- injection
- persistence
- session
- update
- agent-controlled
- unit
- turn
- governance
- opaque
- conflict
- stateless
When to use
Optimised for: Emotion-aware voice agents; therapy + companion apps
Anti-fit: Empathic / emotion focus — overkill if you just want plain voice agent
Pros & cons
Pros
Unique empathic/emotion layer; SOC 2 + HIPAA; founder research credentials; clean SDKs.
Cons
Niche positioning; smaller than Vapi/Retell at agent-orchestration layer; emotion-model interpretability concerns.
Claims & capabilities
$50M Series B Mar-2024 (EQT); proprietary emotion + prosody models; EVI 2 released 2024
Technical surface
- API surface
- WebSocket + REST APIs + SDKs (Python, JS, React Native)
- Backend storage
- Session state in Hume cloud
- Deployment
- Cloud-managed
- Embedding model
- not applicable — not a memory product
- Multi-tenancy
- Multi-tenant cloud
- MCP
- searched not found
- A2A
- searched not found
- OpenTelemetry
- searched not found
Compare Hume EVI with…
Similar systems
Other voice agent platforms in the catalog, ranked by inbound references.
- Cartesia Sonic T1
Cartesia's Sonic TTS — state-space-model-based voice generation, lowest published TTS latency (~40ms). Cartesia raised $64M Series A Q1 2025 (Index + Lightspeed); founded by Mamba authors. Agent platform layer ('Cartesia Line') wraps Sonic with telephony + LLM.
- Vapi T1
Voice-AI developer platform — STT + LLM + TTS pipelines wired to telephony (Twilio / SIP). Used to build outbound + inbound phone agents at scale. Raised $20M Series A from Bessemer + Y Combinator (Dec 2024) at $130M valuation; revenue reported >$10M ARR by Q1 2025.
- Bland AI T1
Voice-AI platform with custom STT + LLM + TTS stack ('the whole pipeline'). Raised $40M Series A Apr-2024 (Lightspeed + Anthology). Distinguished by 'pathway' graphs (deterministic call flows) and aggressive outbound-calling positioning.
- CallRail Conversation Intelligence T2
CallRail's AI-driven conversation intelligence layer atop their call-tracking product. Marketing-vertical voice analytics — auto-tagging, sentiment, lead scoring. CallRail is profitable / private (Sageview-backed); not a voice-agent runtime but the BI / analytics adjacent layer.
- ElevenLabs Conversational AI T1
ElevenLabs launched Conversational AI Nov-2024 — STT + LLM + their own market-leading TTS in one pipeline. Combines vendor's voice cloning + multilingual TTS strengths with hosted call orchestration. ElevenLabs raised $180M Series C Jan-2025 at $3.3B val.
- LiveKit Agents T1
LiveKit Agents — agent framework built on LiveKit's open-source WebRTC media server. LiveKit raised $45M Series B Sep-2024 ($300M val). Powers OpenAI Realtime API's WebRTC transport (LiveKit is the substrate OpenAI chose). Agents framework formally launched 2024.
Related systems
References (2)
- Anthropic Claude (foundation models) depends on at runtime — adjacent-infrastructure cell: Twilio (telephony); Anthropic / OpenAI LLMs (or Hume's eLLM)
- OpenAI GPT family (GPT-5 / GPT-4o / o3 / o4) depends on at runtime — adjacent-infrastructure cell: Twilio (telephony); Anthropic / OpenAI LLMs (or Hume's eLLM)