tools
Empathic Voice Interface (EVI)
EVI is Hume's real-time voice AI for building conversations that respond to vocal expression and emotional context.

In inglese
Empathic Voice Interface measures vocal expression, processes speech and text, and produces streamed speech responses. Developers can connect it to their own language model, configure voices, add tools, inject context, and access transcripts with emotion data.
EVI is designed for embedded voice applications such as assistants, customer service, accessibility tools, games, and robotics. It is a developer API and SDK rather than a standalone consumer chat app. Plans include monthly EVI minutes; additional usage and enterprise limits cost extra.
Features
- Measures vocal expression and responds with emotionally attuned speech
- Supports EVI 3 and EVI 4-mini configurations
- Connects to external language models or Hume's speech-language models
- Streams audio responses in real time with about 300ms time to first byte
- Supports expressive voice selection, voice design, and voice cloning
- Provides interruption, pause, resume, and chat-history controls
- Supports dynamic variables, context injection, and tool use
- Reconstructs complete audio from conversations on demand
Use cases
- Build voice-first AI assistants with natural turn-taking
- Add emotionally responsive voice support to customer-service systems
- Create accessible voice interfaces for applications and services
- Develop conversational characters for games, VR, and immersive experiences
- Connect voice agents to appointments, orders, and other APIs
Pros
Cons
Latest updates
- EVI API additions
Added configurable turn detection and interruption settings to EVI configs.
- EVI API additions
Added support for new supplemental LLM models and zero prompt expansion.
- EVI API additions
Added support for a new SESSION_SETTINGS chat event in the EVI chat history API.
- EVI API additions
Added a control plane API for EVI and a tool call webhook event.
- EVI API improvements
EVI version 4-mini is now available, enabling Octave 2 for TTS alongside a supplemental LLM of your choosing.
Capabilities
- Text to speech — “EVI begins generating speech instantly, streaming audio chunks as they're ready.” source
- Voice cloning — “Choose from a curated library of expressive voices, clone any voice from a sample, or design entirely new voices from natural language descriptions.” source
- Speech to text — “Access complete transcripts with timestamps and emotion data.” source
- API — “Get started in minutes with our intuitive API” source
Get it
Pricing
- Starting price
- $3/mo
- Prices checked
- 2026-09-25
Free
Free
- 10,000 monthly included characters
- 5 minutes monthly EVI usage included
- 15 requests per minute
- 1 concurrent connection
- Unlimited voice cloning (create and use)
Starter
- $3 / month
- 30,000 monthly included characters
- 40 minutes monthly EVI usage included
- 15 requests per minute
- 5 concurrent connections
- Unlimited voice cloning (create and use)
Creator
- $14 / month
- 140,000 monthly included characters
- 200 minutes monthly EVI usage included
- 75 requests per minute
- 5 concurrent connections
- Unlimited voice cloning (create and use)
Pro
- $70 / month
- 1,000,000 monthly included characters
- 1,200 minutes monthly EVI usage included
- 75 requests per minute
- 10 concurrent connections
- Unlimited voice cloning (create and use)
Scale
- $200 / month
- 3,300,000 monthly included characters
- 5,000 minutes monthly EVI usage included
- 150 requests per minute
- 20 concurrent connections
- 3 team seats
- Unlimited voice cloning (create and use)
Business
- $500 / month
- 10,000,000 monthly included characters
- 12,500 minutes monthly EVI usage included
- 225 requests per minute
- 30 concurrent connections
- 5 team seats
- Unlimited voice cloning (create and use)
Enterprise
Price on request
- As much monthly included characters as you need
- As much monthly EVI usage as you need
- As many concurrent connections as you need
- Unlimited voice cloning (create, use and access via API)
- Unlimited team seats
- Slack support