---
title: Introduction
description: BG0 removes image backgrounds locally in your browser. No uploads, accounts, API keys, or server inference.
---

BG0 is an open-source, browser-only background remover. Choose an image, remove its background on your device, and download a transparent PNG. Nothing is uploaded.

**[Web app](/web)**

Drop an image at bg0.parastus.me and download a transparent PNG. Nothing is uploaded.

**[Browser library](/library)**

Add on-device background removal to your own web app.

## How it works

BG0 runs [BiRefNet](https://github.com/ZhengPeng7/BiRefNet), a segmentation model that predicts an alpha mask for the subject of a photo. The mask is composited onto the original pixels to produce a PNG with a transparent background.

The web app and `@bg0/browser` use browser hardware hints to choose whether to attempt a pinned full BiRefNet ONNX model or BiRefNet-lite, with automatic fallbacks if the selected model cannot run. See the [selection rules and verification scope](/library#automatic-model-selection) for details. Images stay on your device throughout selection and fallback.

## Privacy

Image bytes never leave your browser. The web app has no upload step and no account. bg0.parastus.me runs no analytics and collects no image contents or metadata.

## License

BG0 is licensed under Apache 2.0. The model weights carry their own license, documented in the repository's third-party notices.