Bootstrap 4.0.0 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 115048 bytes (112.4k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 48944 bytes (47.8k, 43%).

After GZIP compression these minified files vary in size:

Boot	16088 bytes (15.7k)	CDN
MaxCDN	14848 bytes (14.5k)	CDN
cdnjs	13216 bytes (12.9k)	CDN
gzip -6 (default)	13128 bytes (12.8k)	local copy
Sina	13105 bytes (12.8k)	CDN
Microsoft	13103 bytes (12.8k)	CDN
gzip -9	13069 bytes (12.8k)	local copy
unpkg	13054 bytes (12.7k)	CDN
7zip -mx=9 -tgzip	12661 bytes (12.4k)	local copy
libdeflate -12	12635 bytes (12.3k)	local copy
kzip -s0 -rn -b2	12633 bytes (12.3k)	local copy
pigz -11 -n	12611 bytes (12.3k)	local copy
zultra	12610 bytes (12.3k)	local copy
Zopfli	12595 bytes (12.3k)	local copy
jsdelivr	12031 bytes (11.7k)	CDN

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/bootstrap/bootstrap-4.0.0.min.js (or via HTTPS)

You will automatically get the smallest Bootstrap 4.0.0 file, ETag caching is available and
if your browser doesn't support GZIP decompression then the uncompressed version will be sent.

Currently best Zopfli settings

You can use my super-compressed files for whatever purpose you like as long as you respect the library's original license agreement.
There are no restrictions from my side - but please avoid hot-linking if you run a high-traffic website.

These command-line settings yielded the best compression ratio so far (Linux version of zopfli-krzymod):
zopfli --i100000 --mb8 --mls8192 --bsr9 --lazy --ohh

(found January 19, 2018)

Description	Value	Parameter
iterations	100000	--i100000
maximum blocks	8	--mb8
maximum length score	8192	--mls8192
block splitting recursion	9	--bsr9
lazy matching in LZ77	yes	--lazy
optimized Huffman headers	yes	--ohh
initial random W for iterations	1	--rw1
initial random Z for iterations	2	--rz2

Verify file integrity

After decompression, my uncompressed files are identical to the original ones:

MD5:
curl --silent --compressed https://raw.githubusercontent.com/twbs/bootstrap/v4.0.0/dist/js/bootstrap.min.js --location | md5sum
14d449eb8876fa55e1ef3c2cc52b0c17 -
curl --silent --compressed https://minime.stephan-brumme.com/files/bootstrap/bootstrap-4.0.0.min.zopfli.js.gz | md5sum
14d449eb8876fa55e1ef3c2cc52b0c17 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/twbs/bootstrap/v4.0.0/dist/js/bootstrap.min.js --location | sha1sum
a9545831803b1359cfeed47e3b4d6bae68e40e99 -
curl --silent --compressed https://minime.stephan-brumme.com/files/bootstrap/bootstrap-4.0.0.min.zopfli.js.gz | sha1sum
a9545831803b1359cfeed47e3b4d6bae68e40e99 -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	16088 bytes	14d449eb8876fa55e1ef3c2cc52b0c17	(invalid)
MaxCDN	14848 bytes	14d449eb8876fa55e1ef3c2cc52b0c17	(invalid)
cdnjs	13216 bytes	14d449eb8876fa55e1ef3c2cc52b0c17	(invalid)
Sina	13105 bytes	14d449eb8876fa55e1ef3c2cc52b0c17	April 25, 2019 @ 14:09
Microsoft	13103 bytes	14d449eb8876fa55e1ef3c2cc52b0c17	January 22, 2018 @ 20:17
unpkg	13054 bytes	14d449eb8876fa55e1ef3c2cc52b0c17	(invalid)

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
jsdelivr	12031 bytes	0827a0bdcd9a917990eee461a77dd33e	< * Bootstrap v4.0.0 (https://getbootstrap.com) < * Copyright 2011-2018 The Bootstrap Authors (https://git [...] > * Bootstrap v4.0.0-alpha.6 (https://getbootstrap.com) > * Copyright 2011-2017 The Bootstrap Authors (https://gith [...] < !function(t,e){"object"==typeof exports&&"undefined"!=type [...] < //# sourceMappingURL=bootstrap.min.js.map > if("undefined"==typeof jQuery)throw new Error("Bootstrap's [...] > if(n\|\|(n=new h(this,o),t(this).data(a,n)),"string"==typeof [...]	January 19, 2018 @ 14:17

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

Available Bootstrap versions at minime.stephan-brumme.com:

5.2.3, 5.2.2, 5.2.1, 5.2.0,
5.1.3, 5.1.2, 5.1.1, 5.1.0,
5.0.2, 5.0.1, 5.0.0,
4.6.0,
4.5.3, 4.5.2, 4.5.1, 4.5.0,
4.4.1, 4.4.0,
4.3.1, 4.3.0,
4.2.1, 4.2.0,
4.1.3, 4.1.2, 4.1.1, 4.1.0, 4.0.0,
3.4.1, 3.4.0,
3.3.7, 3.3.6, 3.3.5, 3.3.4, 3.3.2, 3.3.1, 3.3.0,
3.2.0,
3.1.1, 3.1.0,
3.0.3, 3.0.2, 3.0.1, 3.0.0

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, D3, Dojo, Ember, jQuery, Knockout, lodash, React, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:

Size	Improvement	Parameters	Found
12595 bytes	-1 byte	zopfli --i100000 --mls8192 --bsr9 --lazy --ohh	January 19, 2018 @ 15:01
12596 bytes	-1 byte	zopfli --i10000 --mls8192 --bsr9 --lazy --ohh	January 19, 2018 @ 14:40
12597 bytes	-1 byte	zopfli --i10000 --mls8192 --bsr4 --lazy --ohh	January 19, 2018 @ 14:36
12598 bytes	-1 byte	zopfli --i1000 --mls8192 --bsr4 --lazy --ohh	January 19, 2018 @ 14:25
12599 bytes	-1 byte	zopfli --i1000 --mls1024 --bsr18 --lazy --ohh	January 19, 2018 @ 14:25
12600 bytes	-1 byte	zopfli --i1000 --mls256 --bsr22 --lazy --ohh	January 19, 2018 @ 14:25
12601 bytes	–	zopfli --i100 --mls8192 --bsr17 --lazy --ohh	January 19, 2018 @ 14:23

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on July 20, 2020 @ 12:50.

Heatmaps

This Zopfli heatmap visualizes how compression changes when modifying the --bsr and --mls parameter.
Cell's contents is the best filesize achieved (in bytes, hover with mouse over cells to see number of iterations).

Good parameters are green, bad are red. The best and worst are bold as well.
The brightness of the blue background color indicates how many iterations were processed:
10,000, 100,000 or 1,000,000.

bsr \ mls	2	4	8	16	32	64	128	256	512	1024	2048	4096	8192	16384	32768
bsr \ mls	2	4	8	16	32	64	128	256	512	1024	2048	4096	8192	16384	32768
2	12604	12604	12603	12605	12605	12604	12604	12604	12603	12612	12601	12600	12602	12605	12618
4	12604	12604	12605	12604	12603	12604	12605	12603	12598	12599	12606	12601	12596	12599	12614
6	12601	12601	12606	12606	12614	12605	12605	12598	12605	12599	12612	12600	12604	12600	12599
7	12604	12604	12602	12602	12602	12604	12605	12599	12604	12599	12606	12607	12602	12599	12599
8	12601	12601	12604	12605	12604	12604	12605	12600	12601	12612	12606	12599	12600	12605	12604
9	12603	12603	12605	12604	12603	12616	12610	12598	12605	12599	12608	12596	12595	12599	12616
10	12601	12601	12618	12617	12605	12611	12605	12598	12602	12599	12599	12596	12603	12614	12614
11	12604	12604	12604	12604	12611	12602	12605	12599	12601	12598	12607	12600	12597	12601	12609
12	12602	12602	12605	12603	12604	12616	12606	12598	12602	12599	12600	12600	12603	12599	12604
13	12601	12601	12609	12605	12605	12602	12605	12599	12605	12599	12599	12604	12613	12613	12604
14	12606	12606	12605	12605	12603	12616	12612	12598	12599	12599	12607	12600	12602	12613	12599
15	12602	12602	12604	12603	12605	12603	12605	12602	12604	12599	12604	12600	12603	12600	12599
16	12610	12610	12605	12605	12611	12611	12605	12599	12601	12598	12604	12601	12603	12605	12604
17	12605	12605	12605	12605	12611	12604	12605	12599	12605	12599	12595	12596	12596	12605	12600
18	12605	12605	12605	12604	12605	12616	12605	12603	12605	12599	12607	12601	12603	12605	12611
19	12603	12603	12605	12602	12614	12604	12611	12598	12599	12599	12607	12600	12603	12605	12610
20	12603	12603	12617	12605	12603	12604	12605	12598	12602	12599	12614	12603	12603	12605	12602
21	12605	12605	12615	12610	12611	12604	12605	12602	12605	12599	12607	12603	12602	12605	12606
22	12612	12612	12604	12605	12599	12615	12605	12599	12602	12599	12605	12597	12603	12605	12608
23	12602	12602	12605	12605	12603	12604	12605	12598	12602	12599	12604	12600	12603	12600	12614
25	12603	12603	12604	12605	12599	12614	12605	12598	12605	12599	12595	12599	12603	12605	12604
30	12603	12603	12604	12605	12603	12602	12605	12600	12605	12599	12610	12596	12595	12600	12604
40	12601	12601	12604	12604	12603	12605	12605	12604	12602	12599	12609	12599	12603	12604	12614

Due to the Monte Carlo design of my search algorithm, not all parameters have reached the same number of iterations yet:

Iterations	Min. Bytes	Reduction	Coverage
100	12601 bytes	–	100%
1,000	12598 bytes	-3 bytes	100%
10,000	12596 bytes	-2 bytes	100%
100,000	12595 bytes	-1 byte	3.48%
1,000,000	12595 bytes	–	1.16%
10,000,000	–	–	–

KZIP has far less options available for tuning/optimization. I only played around with the number of blocks (parameter -n):

Blocks	Min. Bytes	Compared To Best Zopfli	Compared To Best KZIP
(any)	12666 bytes	+71 bytes (+0.56%)	+33 bytes
1	12667 bytes	+72 bytes (+0.57%)	+34 bytes
2	12633 bytes	+38 bytes (+0.30%)	–
3	12656 bytes	+61 bytes (+0.48%)	+23 bytes
4	12662 bytes	+67 bytes (+0.53%)	+29 bytes
5	12688 bytes	+93 bytes (+0.74%)	+55 bytes
6	12729 bytes	+134 bytes (+1.06%)	+96 bytes
7	12768 bytes	+173 bytes (+1.37%)	+135 bytes
8	12813 bytes	+218 bytes (+1.73%)	+180 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
However, support for Brotli is constantly growing - but your browser doesn't support it.

Algorithm	Program	Parameters	Size	Compared To Best Zopfli
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	10522 bytes	-2073 bytes (-16.46%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	11002 bytes	-1593 bytes (-12.65%)
Brotli (Wikipedia)	brotli	brotli -q 11	11521 bytes	-1074 bytes (-8.53%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	12226 bytes	-369 bytes (-2.93%)
LZMA2 (Wikipedia)	xz	xz -9	12272 bytes	-323 bytes (-2.56%)
Zstandard (Wikipedia)	zstd	zstd -19	12460 bytes	-135 bytes (-1.07%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	12667 bytes	+72 bytes (+0.57%)

Detailled Analysis

I wrote a DEFLATE decoder in Javascript. Click the button below to start a client-side analysis of the smallest gzipped files (may take a second):

Load and Parse Data

Notes: pigz is a fast open source multi-threaded implementation of gzip written by one of the original authors of gzip.
However, when using compression level 11, pigz actually switches to the slower Zopfli algorithm and isn't multi-threaded anymore.
KrzyMOD's extensions to Zopfli offer the highest level of configuration and is therefore used for my brute-force search.
Ken Silverman wrote the closed-source KZIP compression program and Jonathon Fowler ported it to Linux.
Defluff was created by Joachim Henke; DeflOpt is a tool by Ben Jos Walbeehm.

website made by Stephan Brumme in 2015 and still improving in 2024.
all timestamps are displayed in central european time. see my changelog.
no flash, not even images or external css files - and everything squeezed into a single html file.
which was handsomely compressed before releasing it into the wild internet - obviously.

please visit my homepage and my blog, too.
email: minime (at) stephan-brumme.com

All trademarks are property of their respective owners. You know, the boring legal stuff.