favicon-so

favicon.so project API reference — covers the favicon fetch API and image-to-favicon-package convert API. Use when working on API routes, building integrations, debugging favicon fetch/convert behavior, or adding new endpoints to this project.

favicon.so API

API 1: Favicon Fetch

Fetch any website's favicon by domain.

Endpoints

Method	Path	Description
GET	/api/favicon?url={domain}	Fetch favicon with full options
GET	/{domain}	Short URL, returns favicon image directly

Parameters

Param	Type	Required	Description
url	string	yes	Domain or URL (e.g. github.com)
raw	string	no	Set to "true" for JSON metadata instead of image

Response Modes

Image mode (default): Returns binary image data with headers:

• Content-Type: actual image MIME type
• Cache-Control: public, max-age=604800
• Access-Control-Allow-Origin: *

JSON mode (raw=true):

{
  "url": "https://github.githubassets.com/favicons/favicon.svg",
  "format": "image/svg+xml",
  "isDefault": false
}

Implementation

• Source: app/api/favicon/route.ts and app/[locale]/[domain]/route.ts
• Core logic: lib/fetchFavicon.ts — tries HTML parsing, /favicon.ico, Google, DuckDuckGo fallbacks
• Domain validation: lib/utils.ts — normalizeDomain(), isValidDomain()
• Falls back to a default SVG icon when all sources fail

API 2: Image Convert

Convert any image into a complete favicon package with all sizes.

Endpoint

Method	Path	Description
POST	/api/convert	Upload image, get favicon package

Request

Content-Type: multipart/form-data

Field	Type	Required	Description
image	File	yes	Image file (PNG, JPG, WebP, GIF, BMP, TIFF)

Also accepts raw image bytes with Content-Type: image/* or application/octet-stream.

Query Parameters

Param	Type	Default	Description
format	string	—	Set to "json" for base64 JSON output instead of ZIP

Response

ZIP mode (default): Returns application/zip containing 10 files:

• favicon.ico (multi-resolution: 16, 32, 48, 64, 128)
• favicon-16x16.png, favicon-32x32.png, favicon-48x48.png, favicon-64x64.png, favicon-128x128.png
• apple-touch-icon.png (180×180)
• android-chrome-192x192.png, android-chrome-512x512.png
• site.webmanifest

JSON mode (format=json):

{
  "files": {
    "favicon-16x16.png": { "size": 1234, "base64": "iVBOR..." },
    "favicon.ico": { "size": 5678, "base64": "AAAB..." },
    ...
  }
}

Implementation

• Source: app/api/convert/route.ts
• Image processing: jimp (pure JS, Cloudflare Workers compatible)
• ICO generation: custom multi-resolution ICO builder
• ZIP packaging: jszip
• CORS enabled, no auth required

Architecture Notes

• All API routes are in app/api/ and skip the i18n middleware
• The [locale]/[domain]/route.ts catch-all serves as a short URL for favicon fetch
• Reserved paths (search, convert, api, generator, skill, mcp) are excluded from the domain catch-all
• Client-side convert page (app/[locale]/convert/page.tsx) uses WASM (Photon + resvg) for browser-native processing
• Server-side convert API uses jimp for Node.js/Workers compatibility