Hume AI

Hume AI builds voice AI that models emotion. Its two developer products are EVI, the Empathic Voice Interface, a speech to speech conversational engine that hears tone as well as words, and Octave, a text to speech model that takes acting instructions to shape delivery. The company's home page now leads with a third strand, describing Hume as the data and evaluation layer for emotionally intelligent voice AI, with the Kairos simulation platform, an Expression Measurement API, a Human Feedback API and custom data collection. It is a developer platform, not an end user app. EVI runs interruptible conversations, works with Claude, GPT, Gemini, Grok and other language models, supports tool use and context injection, returns emotion data with the chat history and starts speaking in roughly 300 milliseconds, with a HIPAA option for healthcare. Octave offers a voice library, cloning from a sample, voice design from a text description, speech in more than 16 languages, word and phoneme timestamps and MP3, WAV, OGG, FLAC and PCM output. The Expression Measurement API scores voice across more than 48 emotion categories in more than 50 languages. Free is $0 with 10,000 characters and 5 minutes of EVI per month. Starter is $3 per month with 30,000 characters and 40 EVI minutes at $0.07 per minute. Creator is $7 per month with 140,000 characters and 200 EVI minutes. Pro is $70 per month with 1,000,000 characters and 1,200 EVI minutes at $0.06 per minute. Scale is $200 per month with 3.3 million characters and 5,000 minutes. Business is $500 per month with 10 million characters and 12,500 minutes. Enterprise is quote based.