Using OpenAI for Speech-to-Text

This guide covers how to use OpenAI's Whisper API for Speech-to-Text with Open WebUI. This provides cloud-based transcription without needing local GPU resources.

Looking for TTS?

See the companion guide: Using OpenAI for Text-to-Speech

Requirements

• An OpenAI API key with access to the Audio API
• Open WebUI installed and running

Quick Setup (UI)

1. Click your profile icon (bottom-left corner)
2. Select Admin Panel
3. Click Settings → Audio tab
4. Configure the following:

Setting	Value
Speech-to-Text Engine	OpenAI
API Base URL	https://api.openai.com/v1
API Key	Your OpenAI API key
STT Model	whisper-1
Supported Content Types	Leave empty for defaults, or set audio/wav,audio/mpeg,audio/webm

5. Click Save

Available Models

Model	Description
whisper-1	OpenAI's Whisper large-v2 model, hosted in the cloud

info

OpenAI currently only offers whisper-1. For more model options, use Local Whisper (built into Open WebUI) or other providers like Deepgram.

Environment Variables Setup

If you prefer to configure via environment variables:

services:
  open-webui:
    image: ghcr.io/open-webui/open-webui:main
    environment:
      - AUDIO_STT_ENGINE=openai
      - AUDIO_STT_OPENAI_API_BASE_URL=https://api.openai.com/v1
      - AUDIO_STT_OPENAI_API_KEY=sk-...
      - AUDIO_STT_MODEL=whisper-1
    # ... other configuration

All STT Environment Variables (OpenAI)

Variable	Description	Default
AUDIO_STT_ENGINE	Set to openai	empty (uses local Whisper)
AUDIO_STT_OPENAI_API_BASE_URL	OpenAI API base URL	https://api.openai.com/v1
AUDIO_STT_OPENAI_API_KEY	Your OpenAI API key	empty
AUDIO_STT_MODEL	STT model	whisper-1
AUDIO_STT_SUPPORTED_CONTENT_TYPES	Allowed audio MIME types	audio/*,video/webm

Supported Audio Formats

By default, Open WebUI accepts audio/* and video/webm for transcription. If you need to restrict or expand supported formats, set AUDIO_STT_SUPPORTED_CONTENT_TYPES:

environment:
  - AUDIO_STT_SUPPORTED_CONTENT_TYPES=audio/wav,audio/mpeg,audio/webm

OpenAI's Whisper API supports: mp3, mp4, mpeg, mpga, m4a, wav, webm

Using STT

1. Click the microphone icon in the chat input
2. Speak your message
3. Click the microphone again or wait for silence detection
4. Your speech will be transcribed and appear in the input box

OpenAI vs Local Whisper

Feature	OpenAI Whisper API	Local Whisper
Latency	Network dependent	Faster for short clips
Cost	Per-minute pricing	Free (uses your hardware)
Privacy	Audio sent to OpenAI	Audio stays local
GPU Required	No	Recommended for speed
Model Options	whisper-1 only	tiny, base, small, medium, large

Choose OpenAI if:

• You don't have a GPU
• You want consistent performance
• Privacy isn't a concern

Choose Local Whisper if:

• You want free transcription
• You need audio to stay private
• You have a GPU for acceleration

Troubleshooting

Microphone Not Working

1. Ensure you're using HTTPS or localhost
2. Check browser microphone permissions
3. See Microphone Access Issues

Transcription Errors

1. Check your OpenAI API key is valid
2. Verify the API Base URL is correct
3. Check container logs for error messages

Language Issues

OpenAI's Whisper API automatically detects language. If you need to force a specific language, consider using Local Whisper with the WHISPER_LANGUAGE environment variable.

For more troubleshooting, see the Audio Troubleshooting Guide.

Cost Considerations

OpenAI charges per minute of audio for STT. See OpenAI Pricing for current rates.

tip

For free STT, use Local Whisper (the default) or the browser's Web API for basic transcription.