Hume AI is an emotion-focused voice AI platform built around Octave, a text-to-speech engine that lets you direct the emotional delivery of a line — tone, pacing, emphasis, mood — with plain-language "acting instructions" rather than SSML tags. It is aimed at developers, product teams and creators who need expressive, controllable voice for apps, games, audiobooks and voice agents, alongside a speech-to-speech interface (EVI) and an emotion-measurement API. Pricing runs on a tiered monthly-credit model from a free plan through Enterprise, priced by included characters/minutes rather than a flat seat fee.
Who builds it
Hume AI is a voice and emotion-AI research company founded in 2021 by CEO Alan Cowen, a computational emotion scientist who previously led affective-computing research at Google. The company's core workflow is: pick or design a voice, write a script, optionally attach a natural-language "acting instruction" to steer delivery, and generate speech through Octave (TTS) or hold a live conversation through EVI (speech-to-speech); both sit on top of Hume's emotion-science research.
Core features
- Octave TTS with acting instructions — direct tone, pacing, emphasis and mood per line using natural-language instructions instead of SSML.
- Voice cloning and voice design — clone a voice from as little as 15 seconds of sample audio, or design an entirely new voice from a text description.
- Multilingual generation — Octave 2 (launched October 2025) produces speech in 11 languages (English, Spanish, French, German, Italian, Portuguese, Russian, Arabic, Hindi, Japanese, Korean), versus English and Spanish only on Octave 1.
- Low-latency streaming — Octave 2 targets roughly 100ms model latency with unidirectional HTTP and bidirectional WebSocket streaming for real-time use.
- EVI speech-to-speech — a separate empathic voice interface that responds to a caller's tone and prosody in real time, for voice agents and assistants.
- Word/phoneme-level timestamps and format flexibility — outputs in MP3, WAV or PCM with speed control from 0.25x to 4x.
Pricing
Hume prices by monthly included characters (Octave) and EVI minutes, not by voice count:
- Free ($0/month): 10,000 TTS characters (~10 minutes), 5 EVI minutes, 15 requests/minute, unlimited voice cloning, non-commercial use only.
- Starter ($3/month intro): 30,000 characters (~30 minutes), 40 EVI minutes — still non-commercial use only.
- Creator ($7/month intro, $14/month regular): roughly 140,000 characters and 200 EVI minutes; this is the first tier with a commercial license.
- Pro ($70/month): 1,000,000 characters (~1,000 minutes), 1,200 EVI minutes, 10 concurrent connections.
- Scale ($200/month): 3,300,000 characters (~3,300 minutes).
- Business ($500/month): 10,000,000 characters (~10,000 minutes), 12,500 EVI minutes, 5 seats.
- Enterprise: custom pricing with unlimited seats, custom rate limits and compliance features.
Paid tiers can buy overage at a fixed rate per 1,000 characters; Free and Starter cannot.
Who it's for
Hume AI fits developers and product teams building voice agents, games or interactive content that need emotionally directed speech rather than flat narration, and researchers or hobbyists who want to test Octave and EVI cheaply. The Free and Starter plans are enough to prototype and evaluate quality but are restricted to non-commercial use with small monthly quotas; anyone shipping a commercial product needs at least the Creator plan, and high-volume production use (long-form audiobooks, large-scale voice agents) points toward Pro, Scale or Business.