Address review feedback: normalize the base URL by removing trailing
slashes to prevent double-slash paths like /v1//audio/speech which
cause 404 errors on some OpenAI-compatible servers.
Add OPENAI_TTS_BASE_URL environment variable to allow using self-hosted
or third-party OpenAI-compatible TTS services like Kokoro, LocalAI, or
OpenedAI-Speech.
Changes:
- Add OPENAI_TTS_BASE_URL env var (defaults to OpenAI official API)
- Relax model/voice validation when using custom endpoints
- Add tts-1 and tts-1-hd to the model allowlist
This enables users to:
- Use local TTS for privacy and cost savings
- Use models with better non-English language support (Chinese, Japanese)
- Reduce latency with local inference
Example usage:
OPENAI_TTS_BASE_URL=http://localhost:8880/v1
Tested with Kokoro-FastAPI.
