Izwi

Local-first audio inference engine for TTS, ASR, and voice AI workflows.

Website • Documentation • Releases • Getting Started

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Overview

Izwi is a privacy-focused audio AI platform that runs entirely on your machine. No cloud services, no API keys, no data leaving your device.

Core capabilities:

• Voice Mode — Real-time voice conversations with AI
• Text-to-Speech — Generate natural speech from text
• Studio — Build long-form TTS projects and exports
• Speech Recognition — Convert audio to text with high accuracy
• Speaker Diarization — Identify and separate multiple speakers
• Voice Cloning — Clone any voice from a short audio sample
• Voice Design — Create custom voices from text descriptions
• Forced Alignment — Word-level audio-text alignment
• Chat — Text-based AI conversations

The server exposes OpenAI-compatible API routes under /v1. When the server is running, the local Scalar API reference is available at http://localhost:8080/docs, and the raw OpenAPI document is available at http://localhost:8080/openapi.json. Scalar includes navigation entries for preview first-party, operator, and realtime route families; detailed guidance is documented in the API Reference.

Runtime Support Matrix

Backend support depends on both the host and the artifact you install.

• macOS on Apple Silicon: Metal is the recommended and stable GPU path.
• Linux and Windows GitHub Release artifacts: public commands remain izwi / izwi-server and their Windows .exe counterparts, and are intentionally CPU-only.
• Source builds: CUDA is supported when you build with --features cuda on a compatible NVIDIA host.
• Docker CUDA profile: the CUDA distribution path for NVIDIA Linux hosts; when building on a machine without nvidia-smi, set CUDA_COMPUTE_CAP for the target GPU architecture.

See the full Runtime Support Matrix.

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Quick Install

macOS

Download the latest .dmg from GitHub Releases:

1. Open the .dmg file
2. Drag Izwi.app to Applications
3. Launch Izwi

Linux

wget https://github.com/izwi-ai/izwi/releases/latest/download/izwi_amd64.deb
sudo dpkg -i izwi_amd64.deb

Windows

Download and run the installer from GitHub Releases.

Full installation guides: macOS • Linux • Windows • From Source

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Quick Start

1. Start the server

izwi serve

Open http://localhost:8080 in your browser.

API users can also open http://localhost:8080/docs for the local Scalar API reference.

2. Download a model

izwi pull Qwen3-TTS-12Hz-0.6B-Base

3. Generate speech

izwi tts "Hello from Izwi!" --output hello.wav

4. Transcribe audio

izwi pull Parakeet-TDT-0.6B-v3
izwi transcribe audio.wav

Long-form ASR is handled automatically: Izwi now chunks long recordings, stitches overlapping transcripts, and returns a full transcript instead of only the first model window.

Optional tuning knobs:

IZWI_ASR_CHUNK_TARGET_SECS=24
IZWI_ASR_CHUNK_MAX_SECS=30
IZWI_ASR_CHUNK_OVERLAP_SECS=3
# Optional: preload models at server startup to reduce first-request cold latency.
# Comma-separated model IDs (for example Whisper-Large-v3-Turbo,Qwen3.5-4B)
IZWI_PRELOAD_MODELS=Whisper-Large-v3-Turbo
# Optional: run a short synthetic ASR warmup after preloading (enabled by default).
IZWI_WARMUP_PRELOADED_MODELS=1
IZWI_ASR_WARMUP_DURATION_MS=800
# Optional: tune text streaming queue depth when using per-character ASR streaming.
IZWI_STREAM_TEXT_QUEUE_CAPACITY=4096

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Anonymous Analytics (Desktop)

Izwi desktop supports optional, opt-in anonymous usage analytics powered by Aptabase.

• Disabled by default until users explicitly opt in.
• Can be enabled during onboarding or later in Settings.
• Users can opt out at any time.
• No prompts, transcripts, audio payloads, local paths, or personal identifiers are sent.

To enable analytics transport in the desktop shell, set the app key in the runtime environment:

APTABASE_APP_KEY=A-US-XXXXXXXXXXXXXXX

Use the exact key from Aptabase (for example A-US-... or A-EU-...).

Without this variable, analytics calls are treated as no-op events.

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Supported Models

Category	Models
TTS	Qwen3-TTS 12Hz (0.6B Base/CustomVoice, 1.7B Base/CustomVoice/VoiceDesign), Kokoro-82M
ASR	Qwen3-ASR GGUF (0.6B, 1.7B), Parakeet-TDT-0.6B-v3, Whisper-Large-v3-Turbo
Diarization	Sortformer 4-speaker
Chat	Qwen3 GGUF (0.6B, 1.7B, 4B, 8B), Qwen3.5 GGUF (0.8B, 2B, 4B, 9B), LFM2.5 (1.2B Instruct/Thinking GGUF), Gemma 3 (1B)
Audio	LFM2.5-Audio-1.5B-GGUF
Alignment	Qwen3-ForcedAligner-0.6B (full, 4-bit)

Run izwi list to see all available models.

Full model documentation: Models Guide

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Documentation

Resource	Link
Getting Started	izwiai.com/docs/getting-started
Installation	izwiai.com/docs/installation
Features	izwiai.com/docs/features
CLI Reference	izwiai.com/docs/cli
API Reference	izwiai.com/docs/api
Models	izwiai.com/docs/models
Local OpenAPI Reference	http://localhost:8080/docs when izwi serve is running
Troubleshooting	izwiai.com/docs/troubleshooting

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License

Apache 2.0

Acknowledgments

• Qwen3-TTS by Alibaba
• Parakeet by NVIDIA
• Gemma by Google
• HuggingFace Hub for model hosting