favicon.blueat.net#

The fastest way to fetch favicons for any website.

A Cloudflare Worker that fetches a website’s favicon by domain, caches responses at the edge, and returns the image (or a redirect fallback).

Endpoint#

GET https://favicon.blueat.net/{domain}
GET https://favicon.blueat.net/{domain}?larger=true

Parameters#

Parameter	Default	Description
`larger`	`false`	Return a high-res icon (128px+). Prefers SVG, then large PNG.
`default-avatar`	—	URL to redirect to when no favicon is found. Must be URL-encoded.
`throw-error-on-404`	`false`	Return HTTP 404 instead of a placeholder when no favicon is found.

Examples#

HTML#

<!-- Standard 16px favicon -->
<img src="https://favicon.blueat.net/github.com"
     width="16" height="16" alt="GitHub" />

<!-- High-resolution (128px+) -->
<img src="https://favicon.blueat.net/github.com?larger=true"
     width="64" height="64" alt="GitHub" />

<!-- Custom fallback when no favicon is found -->
<img src="https://favicon.blueat.net/unknown.xyz?default-avatar=https%3A%2F%2Fexample.com%2Fdefault.png"
     width="16" height="16" alt="favicon" />

JavaScript#

const res = await fetch("https://favicon.blueat.net/github.com?larger=true");
const blob = await res.blob();
document.getElementById("icon").src = URL.createObjectURL(blob);

How it works#

Check the Workers cache for this domain (and larger flag).
If larger, try Google’s favicon service at 128px.
Otherwise fetch the site HTML and parse <link rel="icon"> / apple-touch-icon tags.
Fall back to /favicon.ico, then Google’s 32px favicon.
If nothing works, redirect to a default image or your default-avatar, or return 404 when requested.

Why might a favicon not be found?#

Reason	Details
Site has no favicon	The domain has no `/favicon.ico`, no `<link rel="icon">` tag, and Google has no cached icon for it. Rare for established sites, common for new or private ones.
Site blocks bots	The domain's server returns a 403 or 429 for automated requests, preventing the HTML parse step. The `/favicon.ico` direct fetch and Google S2 fallbacks are still attempted.
Request timeout	Each upstream fetch has a 5 second timeout. Slow or unresponsive origins will be skipped. If all strategies time out, the fallback image is returned.
Icon behind authentication	Some sites only serve their favicon to authenticated users, so the HTML fetch returns a login page with no `<link>` tags pointing to a real icon.
Non-standard content type	The worker validates that responses have an image content type (`image/*`, icon, svg, or octet-stream). Files served with an unexpected content type are rejected.
Domain doesn't exist	DNS resolution fails for the domain, so all direct fetch strategies return nothing. Google S2 is still tried as a last resort since Google may have a cached record.
Icon is an inline data URI	Some sites embed their icon directly as a `data:` URL in the `<link>` tag. These are intentionally skipped — only external URLs are fetched.

Try it#


default	https://favicon.blueat.net/BlueAT.net
larger=true	https://favicon.blueat.net/BlueAT.net?larger=true

Development & deploy#

npm install
npm run dev

Open http://localhost:8787/github.com while dev is running.

Deploy:

npx wrangler login   # once per machine
npm run deploy

Edit wrangler.toml and set name to the Worker name you want in Cloudflare.

Files#

worker.js — Worker entrypoint
wrangler.toml — Wrangler project config

License#

Use and modify as you like for your own deployment.

Configure Feed