How to save up another precious HTTP-request for the tiny favicon?

javascript html css performance favicon

Everybody knows how to set up a favicon.ico link in their HTML:

<link rel="shortcut icon" href="http://hi.org/icon.ico" type="image/x-icon">

But it's silly that for only a several-byte-tiny icon we need yet yet another potentially speed-penalizing HTTP request.

So I wondered, how could I make that favicon part of a usable sprite (e.g., background-position=0px -200px;) that doubles as, say, a logo on the rest of the website, in order to speed up the site and save that precious and valuable HTTP request. How can we get this to go into an existing sprite image along with our logo and other artworks?

Isn't it silly that there isn't yet a way to combine .css/.js/.png/.html into one single optimized stream? You would've thought someone would have come up with this idea by now

@Richard related: Multipart responses and Google have an initiative for a new, optimized web protocol that solves this, I forgot its name... Edit: It's named SPDY. But that is far in the future, obviously.

@Richard aka cyberkiwi, you can put everything in an html file with data: values for images, and scripts inline.

btw, nice sketch man :)

Looks like that's how you your earned your other Gold badges, you keep renewing the bounty on the same question over and over until you have 100 upvotes, then you earn a gold badge. Slick.

James Anderson

I think for the most part it does not result in another HTTP request as these are usually dumped in the browser's cache after the first access.

This is actually more efficient than any of the proposed "solutions".

This is the only sensible answer. This is a non-issue that doesn't require fixing.

James, my solution is really only a possibility, but one that I would never actually recommend to someone. But, it does seem that most browsers will issue a new HTTP request for the favicon at the beginning of a new browser session. And, it doesn't always return a 304.

The browser will still make a HEAD call even if it's in the browser cache so you will still have the overhead of an HTTP request.

Actually everything depends on the browser. Most of them will always look for for a favicon in some locations even if the page doesn't mention it and make a HEAD call for every refresh.

The favicon needs a long expiring header just like any good static resource. With that, even the HEAD calls are suppressed.

Peter Mortensen

A minor improvement to @yc's answer is injecting the Base64-encoded favicon from a JavaScript file that would normally be used and cached anyway, and also suppressing the standard browser behavior of requesting favicon.ico by feeding it a data URI in the relevant meta tag.

This technique avoids the extra http request and is confirmed to work in recent versions of Chrome, Firefox and Opera on Windows 7. However it doesn't appear to work in Internet Explorer 9 at least.

File index.html

<!doctype html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <!-- Suppress browser request for favicon.ico -->
        <link rel="shortcut icon"type="image/x-icon" href="data:image/x-icon;,">
        <script src="script.js"></script>
...

File script.js

var favIcon = "\
iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAABrUlEQVR42mNkwAOepOgxMTD9mwhk\
[...truncated for brevity...]
IALgNIBUQBUDAFi2whGNUZ3eAAAAAElFTkSuQmCC";

var docHead = document.getElementsByTagName('head')[0];
var newLink = document.createElement('link');
newLink.rel = 'shortcut icon';
newLink.href = 'data:image/png;base64,'+favIcon;
docHead.appendChild(newLink);

/* Other JavaScript code would normally be in here too. */

Demo: turi.co/up/favicon.html

+1 beautiful cached breakthrough @Marcel. PS The characters in the HTTP Headers Response of my .ico file is almost the same size of my icon!! How do you like that?

@Sam: I noticed the base64 of a PNG equivalent of the Stack Overflow favicon.ico file was half the size. Nice and compact.

eeehm i'm not sure wether I understand what you mean: 'file was half the size of ...? PNG file like icon.png? or do you mean the base64 equivalent of it is smaller when its png formatted in stead of icon formatted or gif? curious. Cheers mate!

@Sam: I was comparing the base64 of this PNG to the base64 of this ICO file. The PNG version, as used in my example code above, is half the size.

ooh I see, that makes your base 64 answer, and general use of base64 PNG format the prefered choice then right?

Peter Mortensen

You could try a data URI. No HTTP request!

<link id="favicon" rel="shortcut icon" type="image/png" href="data:image/png;base64,....==">

Unless your pages have static caching, your favicon wouldn't be able to be cached, and depending on the size of your favicon image, your source code could get kind of bloated as a result.

Data URI favicons seems to work in most modern browsers; I have it working in recent versions of Chrome, Firefox and Safari on a Mac. Doesn't seem to work in Internet Explorer, and possibly some versions of Opera.

If you're worried about old Internet Explorer versions (and you probably shouldn't be these days), you could include an Internet Explorer conditional comment that would load the actual favicon.ico in the traditional way, since it seems that older Internet Explorer doesn't support data URI favicons.

`<!--[if IE ]><link rel="shortcut icon" href="http://example.com/favicon.ico"  type="image/x-icon" /><![endif]--> `

Include the favicon.ico file in your root directory to cover browsers that will request it either way, since for those browsers, if they're already checking no matter what you do, you might as well not waste the HTTP request with a 404 response.

You could also just use the favicon of another popular site which is likely to have their favicon cached, like http://google.com/favicon.ico, so that it is served from cache.

As commenters have pointed out, just because you can do this doesn't mean you should, since some browsers will request favicon.ico regardless of the tricks we devise. The amount of overhead you'd save by doing this would be minuscule compared to the savings you'd get from doing things like gzipping, using far-future expires headers for static content, minifying JavaScript files, putting background images into sprites or data URIs, serving static files off of a CDN, etc.

@Pekka yeah, its not really a practical solution, since the data URI extra byte-weight on un-cached pages would probably outweigh the weight of that HTTP request. Maybe OP can inject the favicon into the DOM asynchronously.

@Sam I'm sorry, I understand what @yc means now, my mistake. Of course you can perfectly access the <link rel> element in the browser through JavaScript, that should be possible. I have even seen a game programmed that way... however it does not seem to work in IE, either, and it will probably not prevent the default /favicon.ico lookup request

@Pekka, I see. PS thats an increcible game! Puts my entire screen realestate into shame, since all you need is that 16x16 pixels haha. This hyperlink opens some possibilities as to whats actually possible with that favicon.

In case of a missing favicon declaration, all browsers will automatically request the default URL /favicon.ico in a blind attempt at locating it. So if you leave out the favicon <link> (to later add it via Javascript) you're likely just making things worse.

Just use favicon.ico to store your transparant gif :)

Rounin - Standing with Ukraine

Killer Solution in 2020

This solution necessarily comes nine years after the question was originally asked, because, until fairly recently, most browsers have not been able to handle favicons in .svg format.

That's not the case anymore.

See: https://caniuse.com/#feat=link-icon-svg

1) Choose SVG as the Favicon format

Right now, in June 2020, these browsers can handle SVG Favicons:

Chrome

Firefox

Edge

Opera

Chrome for Android

KaiOS Browser

Note that these browsers still can't:

Safari

iOS Safari

Firefox for Android

Nevertheless, with the above in mind, we can now use SVG Favicons with a reasonable degree of confidence.

2) Present the SVG as a Data URL

The main objective here is to avoid HTTP Requests.

As other solutions on this page have mentioned, a pretty smart way to do this is to use a Data URL rather than an HTTP URL.

SVGs (especially small SVGs) lend themselves perfectly to Data URLs, because the latter is simply plaintext (with any potentially ambiguous characters percentage-encoded) and the former, being XML, can be written out as a long line of plaintext (with a smattering of percentage codes) incredibly straightforwardly.

3) The entire SVG is a single Emoji

N.B. This step is optional. Your SVG can be a single emoji, but it can just as easily be a more complex SVG.

In December 2019, Leandro Linares was one of the first to realise that since Chrome had joined Firefox in supporting SVG Favicons, it was worth experimenting to see if a favicon could be created out of an emoji:

https://lean8086.com/articles/using-an-emoji-as-favicon-with-svg/

Linares' hunch was right.

Several months later (March 2020), Code Pirate Lea Verou realised the same thing:

https://twitter.com/leaverou/status/1241619866475474946

And favicons were never the same again.

4) Implementing the solution yourself:

Here's a simple SVG:

<svg
  xmlns="http://www.w3.org/2000/svg"
  viewBox="0 0 16 16">

  <text x="0" y="14">🦄</text>
</svg>

And here's the same SVG as a Data URL:

data:image/svg+xml,%3Csvg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='0%200%2016%2016'%3E%3Ctext%20x='0'%20y='14'%3E🦄%3C/text%3E%3C/svg%3E

And, finally, here's that Data URL as a Favicon:

<link rel="icon" href="data:image/svg+xml,%3Csvg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='0%200%2016%2016'%3E%3Ctext%20x='0'%20y='14'%3E🦄%3C/text%3E%3C/svg%3E" type="image/svg+xml" />

5) More tricks (...these are not your parents' favicons!)

Since the Favicon is an SVG, any number of filter effects (both SVG and CSS) can be applied to it.

For instance, alongside the White Unicorn Favicon above, we can easily make a Black Unicorn Favicon by applying the filter:

style="filter: invert(100%);"

Black Unicorn Favicon:

<link rel="icon" href="data:image/svg+xml,%3Csvg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='0%200%2016%2016'%3E%3Ctext%20x='0'%20y='14'%20style='filter:%20invert(100%);'%3E🦄%3C/text%3E%3C/svg%3E" type="image/svg+xml" />

Thanks Rounin! Brilliant! SVG is resizable too so in another 9 years we will have an option to choose how large we want favicons to be on webbrowser tabs. Choose from: 16x16 32x32 64x64 128x128 Being the original poster, its invigorating to see 9 years later folks still care, about the little things that make life more beautiful, more enjoyable, snappier or just more elegant! :)

Your question was entirely prescient, @Sam. When you asked it in 2011, Steve Souders had long established that round-trips to the server should be eliminated wherever possible. But for years afterwards, the favicon defiantly demanded its own dedicated round-trip. Thankfully that's no longer the case due to the (belated but much welcomed) collective support from the browser makers for SVG-based favicons. (I only came across this issue in my endeavour - still a work-in-progress, but I'll return to it soon - to create a single-file Progressive Web App.

<IMG src="data:image/svg..."> has worked for years, I use it in the 52 PlayingCards Custom Element I presume they use the same parsing code for favicon. No need to escape everything for the DataURI, Only escape # and use single quotes only. The xlink is deprecated, not required. Brings the data URI down to: data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'><text x='0' y='14'>🦄</text></svg> (tested in Chrome)

After some tweaking of viewBox to 20x20 and x,y positions to -1,15.5 I would say this is the playground to start from when using Emoji characters:

href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'><rect width='100%' height='100%' fill='hotpink'/><text x='-1' y='15.5' stroke='red'>😎</text></svg>"

(tested on Chrome & FireFox) Firefox respects the Emoji icon color designs, Chrome does not.

Good contributions, @Danny'365CSI'Engelman, thanks. I wasn't aware that xlink:href is now deprecated but I've removed it from wherever it appeared above anyway since it had no business being in a favicon SVG. Separately, I see your argument for replacing %20 with whitespace literals but I'm reluctant... because, copy-pasted and edited by laypeople, whitespace literals can become newline literals etc.

Peter Mortensen

You could use a Base64-encoded favicon, like:

<link href="data:image/x-icon;base64,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" rel="icon" type="image/x-icon" />

Hint: the base64 encoded string used in this answer is a PNG file and will not work with IE10 or older.

In case anyone wants to know It is the linux penguin.

Peter Mortensen

I found an interesting solution on this page. It is in German, but you will be able to understand the code.

You put the base64 data of the icon into an external style sheet, so it will be cached. In the head of your website you have to define the favicon with an id and the favicon is set as a background-image in the style sheet for that id.

link#icon {
    background-image:url("data:image/x-icon;base64,<base64_image_data>");
}

and the html

<html>
    <head>
        <link id="icon" rel="shortcut icon" type="image/x-icon" />
        <link rel="stylesheet" type="text/css" href="/styles.css" />
        ...
    </head>
    <body>
        ...
    </body>
</html>

One person with 74.947 reputation said somewhere on this page: "You can't!" ... Then another person with less than 50 reputation said: "You can!" Does this mean that drive for solutions and concrete innovative drive have no links or relations with gained reputation? ... Well then thats just awesome!

I've just confirmed that this solution does not work - at least not in Chrome 10 and Firefox 3.6 on Windows

I've just confirmed that this solution does work - at least in Chrome 10.0.648 on W7 64 bit and in FF 4.0 on W7 64bit

LOL, I've confirmed the above two statements seem contradictory, despite the slightly different version numbers I doubt the behavior of Chrome changed that much. Firefox maybe did from 3.6 to 4, but unlikely Chrome 10 changed that much on a minor update.

I can confirm that this does work on Chrome 83 and Firefox ESR 68 on Ubuntu 20.04, and I can confirm that it does not work to prevent the hit on /favicon.ico. So you get the image but you do not prevent the extra SSL connect. Since that was the goal, this is a failure.

Pekka

Good point and nice idea, but impossible. A favicon needs to be a single, separate resource. There is no way to combine it with another image file.

Maybe I'm blind, but the only place I'm seeing the Google Search favicon is in a sprite: google.com/search?q=foo

@yc google.com/favicon.ico is the place where browsers will automatically look it up

@yc you are not blind, you proved yourself worthy of a very creative answer up there... as Pekka pointed out already the /favicon.ico is where browsers will auto look. Now comes the real bad news: If the favicon is NON existent, it means an error 404 penalty which will cause a slight delay too!! There seems no escaping from this favicon dungeon. They are so tiny but oh so mighty... dammit :)

See my answer stackoverflow.com/questions/5199902/… for the proper way to speed up the proper way.

It should be noted that this should, realistically, be a one time request, pretty much forever. As with everything else, long cache timers and proper 301's returned by the server will make the favicon request a moot point (unless it doesn't exist - yikes!).

Peter Mortensen

Does it really matter?

Many browsers load the favicon as a low priority so that it doesn't block the page load in anyway, so yes it's an extra request, but it's not on any critical path.

The accepted solution is horrible as until the JavaScript code has been retrieved and executed, all the DOM elements below will be blocked from rendering and it doesn't reduce the number of requests!

Please note that in 2020 a new solution has been accepted, replacing the older accepted solution. This new approach was made possible by most browsers introducing support for SVG favicons in late 2019.

Peter Mortensen

The proper solution is to use HTTP pipelining.

HTTP pipelining is a technique in which multiple HTTP requests are written out to a single socket without waiting for the corresponding responses. Pipelining is only supported in HTTP/1.1, not in 1.0.

It's required that servers support it, but not necessarily participate.

HTTP pipelining requires both the client and the server to support it. HTTP/1.1 conforming servers are required to support pipelining. This does not mean that servers are required to pipeline responses, but that they are required not to fail if a client chooses to pipeline requests.

Many browser clients don't do it, when they should.

HTTP pipelining is disabled in most browsers. Opera has pipelining enabled by default. It uses heuristics to control the level of pipelining employed depending on the connected server. Internet Explorer 8 does not pipeline requests, due to concerns regarding buggy proxies and head-of-line blocking. Mozilla browsers (such as Mozilla Firefox, SeaMonkey and Camino), support pipelining however it is disabled by default. It uses some heuristics, especially to turn pipelining off for IIS servers. Konqueror 2.0 supports pipelining, but it's disabled by default.[citation needed] Google Chrome does not support pipelining.

I would recommend you try enabling pipelining in Firefox and try it there, or just use Opera (shudder).

Pipelining an optimization done in the transport layer. It still involves a separate HTTP round-trip for the favicon, which is what the question asks about.

@Már Örlygsson that is not correct. A round trip means that the client must make a request and then wait for the request to be processed and the answer to be dowloaded. Pipelining means that the request will already be sent while still waiting for the previous request to finish, so while the same steps are happening, the delay it will cause will not be the same...

Sam can't turn pipelining on in all of his visitors' browsers, so in that sense this solution won't make his site load faster - except for him personally.

@Már Örlygsson and his upvoters: It's not done in the tranport layer. In real-world models this is all done in the application layer. Theoretically pipelining should be at the session layer.

I won't argue those semantics with you. The fact still holds that Sam can't "use pipelining" (neat as it is) to make his site load faster for his visitors, as piplining support is A) spotty as you point out yourself, and B) opt-in by each individual user.

Anthony Hatzopoulos

This is not really an answer to the question, but simply to compliment the answers given by Marcel and yahelc. I offer an elegant solution to the 404 favicon issue.

Some applications and browsers check for a favicon.ico file and if the icon is not found in the site root, you can simply respond to the request with the 204 response header.

Apache Examples:

Apache option one (and my favorite), a simple one-liner in your .htacces or .conf:

Redirect 204 /favicon.ico

Apache option two:

<Files "favicon.ico">
    ErrorDocument 204 ""
</Files>

For further reading there is a nice blog post by Stoyan Stefanov.

Yeh but as the request is being made and the favicon is often used in a meaningful way I reckon it's worthwhile providing the icon rather than an empty response. Compressing the icon via gzip will often get it to a single TCP packet size anyway

Peter Mortensen

It's a great idea, but if Google hasn't done it on their homepage, I'm betting it can't (currently) be done.

Google is great, but thinking like that seems counterproductive and stifling. There are always new, better, and very possible ways of doing things, and you don't have to work for an industry leader to come up with them.

Obviously, Google gets their ideas from SO, not the other way round ;)

Good answer, if google could make their page faster, they would.

Peter Mortensen

I'm sorry, but you can't combine the favicon with another resource.

This means you have basically two options:

If you're comfortable with your site not having a favicon - you can just have the href point to a non-icon resource that is already being loaded (e.g., a style sheet, script file, or even some resource that benefits from being pre-fetched). (My brief testing indicates that this works across most, if not all, major browsers.) Accept the extra HTTP request and just make sure your favicon file has aggressive HTTP cache-control headers set. (If you have other websites under your control, you might even have them sneakily preload the favicon for this website - along with other static resources.)

P.S. Creative solutions that will not work:

The weird CSS data URI trick (linked to by commenter Felix Geenen) does not work.

Using JavaScript to perform a delayed injection of the favicon element (as suggested by user yc) will likely just make things worse - by resulting in two HTTP requests.

other solutions that won't work: multiple icons in a .ico, and using the ico in an image tag in the hope that it will display another picture there, than as favicon. Catting together the favicon with another file.

Peter Mortensen

Here's the easiest way:

<!DOCTYPE html><html><head> 
<link rel="shortcut icon" href="data:image/png;base64,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">
</head></html>

What icon does it represent? Answer below!

The apple icon?

Peter Mortensen

You can use an 8-bit PNG image instead of the ICO format for an even smaller data footprint. The only thing you have to change is using "data:image/png" instead of "data:image/x-icon" MIME type header:

<link
  href="data:image/png;base64,your-base64-encoded-string-goes-here"
  rel="icon" type="image/png"
/>

"type" attribute can be "image/png" or "image/x-icon". Both work for me.

You can convert ICO to 8-bit PNG using GIMP or convert:

convert favicon.ico -depth 8 -strip favicon.png

And encode the PNG binary to a Base64-string using the base64 command:

base64 favicon.png

How to save up another precious HTTP-request for the tiny favicon?

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