# FavGrab — Full Reference

> Free browser-based toolkit for web developers: download favicons from any domain and convert images between common formats without uploads.

## What FavGrab is

FavGrab is a static single-page web app hosted at https://favgrab.boldkit.dev. It offers two tools today:

1. A favicon downloader that fetches the favicon for any domain via Google's public FaviconV2 service, lets the user pick a size (16, 32, 48, 64, 128, or 256 px), and exports it as PNG, WebP, or JPG.
2. A fully client-side image converter that decodes a wide range of input formats and re-encodes them into common web formats, with optional quality control and resizing.

All processing for the image converter runs locally in the visitor's browser. Files never leave the device. There is no upload step, no server-side processing, no signup, no payment, and no per-user tracking.

## Why local-first matters

- Privacy: photos containing faces, documents, screenshots of internal tooling, or other sensitive content stay on the user's machine.
- Speed: the conversion runs at the user's CPU speed with no upload/download round trip. Large files (50 MB+) finish in seconds.
- Offline use: after the first page load, the static assets and lazily fetched WebAssembly codecs are cached by the browser. The converter continues to work without an internet connection.
- Cost: no server compute, so the service is free with no rate limits.

## Image Converter

URL: https://favgrab.boldkit.dev/convert

### Supported input formats

PNG, JPG/JPEG, WebP, AVIF, GIF (first frame only), BMP, ICO, HEIC, HEIF, TIFF.

Decoders:

- PNG, JPG, WebP, AVIF, GIF, BMP, ICO are decoded by the browser's native `createImageBitmap()` API.
- HEIC and HEIF are decoded by `libheif-js` (WebAssembly), loaded on demand the first time a HEIC/HEIF file is dropped.
- TIFF is decoded by `utif2`, loaded on demand.

### Supported output formats

PNG, JPG/JPEG, WebP, AVIF, BMP, ICO.

Encoders:

- PNG, JPG, WebP via the browser's Canvas `toBlob()` API.
- AVIF via `@jsquash/avif` WebAssembly, loaded on demand.
- BMP via a small custom 24-bit BMP writer.
- ICO via a small custom writer that wraps a PNG payload in an ICO container (single image, up to 256×256).

HEIC, HEIF, and TIFF are not offered as output formats because no viable client-side encoders exist for them.

### Options

- Quality: an integer from 1 to 100, default 95, applied to lossy outputs (JPG, WebP, AVIF). PNG and BMP are lossless. ICO embeds a lossless PNG.
- Resize: optional. When enabled, the user provides a max-side value in pixels. Images larger than that on either side are downscaled with high-quality bilinear filtering; the aspect ratio is preserved. Upscaling is never applied.
- Batch: any number of files can be processed. Files are converted sequentially with per-file progress. Results can be downloaded individually or all at once as a streaming ZIP archive (produced with `client-zip`).

### Save behavior

When the browser supports the File System Access API (Chrome, Edge, Opera, Arc on desktop), clicking Download opens the native OS Save As dialog so the user picks a destination folder. Other browsers fall back to standard `<a download>` behavior, which saves to the browser's default Downloads folder unless the user has enabled "ask where to save each file" in browser settings.

## Favicon Downloader

URL: https://favgrab.boldkit.dev/

Enter a domain or full URL. FavGrab requests the favicon via Google's FaviconV2 service and previews it. The user picks a size (16, 32, 48, 64, 128, 256) and a format (PNG, WebP, JPG) and downloads. Recent domains are remembered in-session for quick re-use.

## Tech stack

- React 18 single-page app, built with Vite.
- TypeScript end-to-end.
- Tailwind v4 + a custom BoldKit-styled component layer (`@/components/ui/*`).
- No router library: a 30-line path-based router (`src/lib/router.tsx`) handles `/` and `/convert`.
- Deployed on Vercel as static assets with an SPA rewrite (`vercel.json`).
- Codec dependencies are dynamically imported and code-split, so the initial JS bundle stays around 70 KB gzipped. HEIC, AVIF, and TIFF chunks only load when actually used.

## Privacy & data

- No user accounts.
- No file ever leaves the user's browser for the image converter.
- The favicon downloader proxies a single GET to Google's FaviconV2 endpoint per fetch; no personal data is sent.
- Site-wide analytics use Google Analytics (anonymous traffic counts only).
- No cookies are used for personalization or tracking.

## License & operator

Open source on GitHub: https://github.com/ANIBIT14/favgrab. Operated by Vanikya AI (https://vanikya.ai).