favicon.so API

API 1: Favicon Fetch

Fetch any website's favicon by domain.

Endpoints

Parameters

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

Request

Content-Type: multipart/form-data

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

Query Parameters

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