GPT-SoVITS is a production-grade text-to-speech and voice conversion system with a Gradio-based WebUI and FastAPI REST API. It supports zero-shot voice cloning from a 5-second reference audio and few-shot fine-tuning with 1 minute of data. The system integrates multiple model versions (v1–v4, v2Pro, v2ProPlus) with autoregressive (GPT-style) and non-autoregressive (SoVITS/CFM) components, plus a BigVGAN vocoder. It includes a full pipeline for dataset preparation (voice separation, ASR, text labeling), training (with DDP, LoRA, DPO), and inference (streaming, parallel, ONNX/TorchScript export). The codebase is heavily modular with reusable text frontends for Chinese, Japanese, Korean, Cantonese, and English, as well as audio processing tools (UVR5, BS-Roformer, AP-BWE). Despite its breadth, the code exhibits significant technical debt: version sprawl, hardcoded paths, global state, and experimental hacks. It is actively maintained with frequent bug fixes and feature additions.