Environment Variables

Environment Variables List

info

For a complete list of all Open WebUI environment variables, see the Environment Variable Configuration page.

The following is a summary of the environment variables for speech to text (STT) and text to speech (TTS).

UI Configuration

Most of these settings can also be configured in the Admin Panel → Settings → Audio tab. Environment variables take precedence on startup but can be overridden in the UI.

Speech To Text (STT) Environment Variables

Preprocessing

Variable	Description	Default
BYPASS_PYDUB_PREPROCESSING	Skip pydub-based preprocessing (MP3 conversion, compression, chunk splitting) before sending audio to the STT engine. Applies to all engines. Useful when the upstream provider already handles these steps, or when ffmpeg is unavailable on the host.	false

Local Whisper

Variable	Description	Default
WHISPER_MODEL	Whisper model size	base
WHISPER_MODEL_DIR	Directory to store Whisper model files	{CACHE_DIR}/whisper/models
WHISPER_COMPUTE_TYPE	Compute type for inference (see note below)	int8
WHISPER_LANGUAGE	ISO 639-1 language code (empty = auto-detect)	empty
WHISPER_MULTILINGUAL	Use the multilingual Whisper model	false
WHISPER_MODEL_AUTO_UPDATE	Auto-download model updates	false
WHISPER_VAD_FILTER	Enable Voice Activity Detection filter	false

WHISPER_COMPUTE_TYPE Options

• int8 — CPU default, fastest but may not work on older GPUs
• float16 — Recommended for CUDA/GPU
• int8_float16 — Hybrid mode (int8 weights, float16 computation)
• float32 — Maximum compatibility, slowest

If using the :cuda Docker image with an older GPU, set WHISPER_COMPUTE_TYPE=float16 to avoid errors.

OpenAI-Compatible STT

Variable	Description	Default
AUDIO_STT_ENGINE	STT engine: empty (local Whisper), openai, azure, deepgram, mistral	empty
AUDIO_STT_MODEL	STT model for external providers	empty
AUDIO_STT_OPENAI_API_BASE_URL	OpenAI-compatible API base URL	https://api.openai.com/v1
AUDIO_STT_OPENAI_API_KEY	OpenAI API key	empty
AUDIO_STT_SUPPORTED_CONTENT_TYPES	Comma-separated list of supported audio MIME types	empty

Azure STT

Variable	Description	Default
AUDIO_STT_AZURE_API_KEY	Azure Cognitive Services API key	empty
AUDIO_STT_AZURE_REGION	Azure region	eastus
AUDIO_STT_AZURE_LOCALES	Comma-separated locales (e.g., en-US,de-DE)	auto
AUDIO_STT_AZURE_BASE_URL	Custom Azure base URL (optional)	empty
AUDIO_STT_AZURE_MAX_SPEAKERS	Max speakers for diarization	3

Deepgram STT

Variable	Description	Default
DEEPGRAM_API_KEY	Deepgram API key	empty

Mistral STT

Variable	Description	Default
AUDIO_STT_MISTRAL_API_KEY	Mistral API key	empty
AUDIO_STT_MISTRAL_API_BASE_URL	Mistral API base URL	https://api.mistral.ai/v1
AUDIO_STT_MISTRAL_USE_CHAT_COMPLETIONS	Use chat completions endpoint	false

Text To Speech (TTS) Environment Variables

General TTS

Variable	Description	Default
AUDIO_TTS_ENGINE	TTS engine: empty (disabled), openai, mistral, elevenlabs, azure, transformers	empty
AUDIO_TTS_MODEL	TTS model	tts-1
AUDIO_TTS_VOICE	Default voice	alloy
AUDIO_TTS_SPLIT_ON	Split text on: punctuation, paragraphs, or none	punctuation
AUDIO_TTS_API_KEY	API key for ElevenLabs or Azure TTS	empty

OpenAI-Compatible TTS

Variable	Description	Default
AUDIO_TTS_OPENAI_API_BASE_URL	OpenAI-compatible TTS API base URL	https://api.openai.com/v1
AUDIO_TTS_OPENAI_API_KEY	OpenAI TTS API key	empty
AUDIO_TTS_OPENAI_PARAMS	Additional JSON params for OpenAI TTS	empty

Mistral TTS

Variable	Description	Default
AUDIO_TTS_MISTRAL_API_KEY	Mistral TTS API key	empty
AUDIO_TTS_MISTRAL_API_BASE_URL	Mistral API base URL	https://api.mistral.ai/v1

info

When AUDIO_TTS_ENGINE=mistral, Open WebUI uses mistral-tts-latest when AUDIO_TTS_MODEL is empty.

Azure TTS

Variable	Description	Default
AUDIO_TTS_AZURE_SPEECH_REGION	Azure Speech region	eastus
AUDIO_TTS_AZURE_SPEECH_BASE_URL	Custom Azure Speech base URL (optional)	empty
AUDIO_TTS_AZURE_SPEECH_OUTPUT_FORMAT	Audio output format	audio-24khz-160kbitrate-mono-mp3

Tips for Configuring Audio

Using Local Whisper STT

For GPU acceleration issues or older GPUs, try setting:

environment:
  - WHISPER_COMPUTE_TYPE=float16

Using External TTS Services

When running Open WebUI in Docker with an external TTS service:

environment:
  - AUDIO_TTS_ENGINE=openai
  - AUDIO_TTS_OPENAI_API_BASE_URL=http://host.docker.internal:5050/v1
  - AUDIO_TTS_OPENAI_API_KEY=your-api-key

tip

Use host.docker.internal on Docker Desktop (Windows/Mac) to access services on the host. On Linux, use the host IP or container networking.

For troubleshooting audio issues, see the Audio Troubleshooting Guide.