Bootstrap 3.0.2 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 58327 bytes (57.0k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 27748 bytes (27.1k, 48%).

After GZIP compression these minified files vary in size:

Microsoft	9512 bytes (9.3k)	CDN
Boot	8684 bytes (8.5k)	CDN
MaxCDN	8684 bytes (8.5k)	CDN
cdnjs	7355 bytes (7.2k)	CDN
gzip -6 (default)	7332 bytes (7.2k)	local copy
gzip -9	7314 bytes (7.1k)	local copy
Yandex	7299 bytes (7.1k)	CDN
jsdelivr	7299 bytes (7.1k)	CDN
libdeflate -12	7077 bytes (6.9k)	local copy
7zip -mx=9 -tgzip	7072 bytes (6.9k)	local copy
kzip -s0 -rn -b2	7061 bytes (6.9k)	local copy
zultra	7050 bytes (6.9k)	local copy
pigz -11 -n	7028 bytes (6.9k)	local copy
Zopfli	7020 bytes (6.9k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.2.min.js (or via HTTPS)

You will automatically get the smallest Bootstrap 3.0.2 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

Save 279 bytes by using my Bootstrap 3.0.2 Zopfli version instead of the best available CDN (3.97% smaller than jsdelivr, 7020 vs. 7299 bytes):

Download

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 --mls32768 --bsr23 --lazy --ohh

(found December 1, 2015)

Description	Value	Parameter
iterations	100000	--i100000
maximum blocks	8	--mb8
maximum length score	32768	--mls32768
block splitting recursion	23	--bsr23
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/v3.0.2/dist/js/bootstrap.min.js --location | md5sum
c2e5221c3336abe0dff8568e73cd0dae -
curl --silent --compressed https://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.2.min.zopfli.js.gz | md5sum
c2e5221c3336abe0dff8568e73cd0dae -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/twbs/bootstrap/v3.0.2/dist/js/bootstrap.min.js --location | sha1sum
15a81fe4074f920898e98b1b42cf11bda26da0a8 -
curl --silent --compressed https://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.2.min.zopfli.js.gz | sha1sum
15a81fe4074f920898e98b1b42cf11bda26da0a8 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Microsoft	9512 bytes	c2e5221c3336abe0dff8568e73cd0dae	(invalid)
Boot	8684 bytes	c2e5221c3336abe0dff8568e73cd0dae	(invalid)
MaxCDN	8684 bytes	c2e5221c3336abe0dff8568e73cd0dae	(invalid)
cdnjs	7355 bytes	c2e5221c3336abe0dff8568e73cd0dae	(invalid)
Yandex	7299 bytes	c2e5221c3336abe0dff8568e73cd0dae	(invalid)
jsdelivr	7299 bytes	c2e5221c3336abe0dff8568e73cd0dae	(invalid)

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
7020 bytes	-1 byte	zopfli --i100000 --mls32768 --bsr23 --lazy --ohh	December 1, 2015 @ 09:57
7021 bytes	-1 byte	zopfli --i10000 --mls8192 --bsr11 --lazy --ohh	September 10, 2015 @ 19:47
7022 bytes	-1 byte	zopfli --i10000 --mls2048 --bsr9 --lazy --ohh	September 10, 2015 @ 19:38
7023 bytes	-1 byte	zopfli --i1000 --mls4096 --bsr9 --lazy --ohh	September 10, 2015 @ 16:53
7024 bytes	–	zopfli --i100 --mls8192 --bsr14 --lazy --ohh	September 10, 2015 @ 16:27

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 @ 12:53.

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	7029	7029	7037	7038	7037	7035	7035	7036	7035	7024	7025	7024	7021	7023	7023
4	7033	7033	7033	7033	7033	7034	7026	7024	7033	7026	7025	7027	7027	7026	7023
6	7024	7024	7024	7025	7025	7025	7026	7024	7030	7029	7025	7022	7024	7023	7022
7	7034	7034	7032	7033	7033	7024	7024	7023	7028	7026	7026	7023	7024	7023	7026
8	7033	7033	7029	7034	7033	7025	7024	7024	7028	7025	7025	7022	7022	7023	7023
9	7033	7033	7032	7032	7025	7025	7032	7024	7028	7025	7022	7023	7023	7023	7023
10	7033	7033	7032	7029	7026	7025	7025	7023	7029	7024	7024	7025	7024	7023	7023
11	7034	7034	7026	7035	7025	7024	7034	7024	7028	7025	7026	7024	7021	7023	7023
12	7034	7034	7032	7024	7025	7025	7034	7024	7028	7025	7026	7022	7026	7022	7025
13	7033	7033	7032	7034	7025	7024	7025	7024	7028	7029	7026	7023	7022	7023	7022
14	7033	7033	7025	7025	7025	7024	7033	7025	7025	7026	7026	7024	7022	7022	7023
15	7032	7032	7032	7032	7029	7025	7025	7023	7028	7025	7026	7023	7023	7023	7020
16	7034	7034	7032	7033	7025	7025	7025	7023	7028	7025	7025	7023	7026	7027	7023
17	7034	7034	7032	7033	7024	7024	7026	7026	7028	7025	7024	7023	7022	7022	7025
18	7033	7033	7032	7033	7024	7024	7025	7024	7028	7025	7026	7022	7021	7024	7020
19	7034	7034	7032	7033	7025	7025	7024	7025	7025	7021	7026	7024	7021	7026	7026
20	7033	7033	7024	7033	7034	7025	7025	7029	7025	7025	7026	7024	7024	7023	7022
21	7033	7033	7032	7033	7025	7024	7026	7024	7023	7025	7025	7024	7024	7023	7020
22	7024	7024	7032	7027	7024	7024	7024	7025	7028	7025	7024	7022	7021	7022	7020
23	7034	7034	7032	7033	7025	7033	7026	7025	7028	7025	7025	7026	7021	7023	7020
25	7034	7034	7032	7035	7025	7025	7024	7024	7028	7025	7026	7022	7021	7022	7023
30	7033	7033	7032	7034	7032	7034	7025	7024	7029	7025	7026	7024	7023	7022	7023
40	7033	7033	7033	7033	7033	7033	7025	7024	7028	7025	7026	7023	7021	7023	7023

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	7023 bytes	–	100%
1,000	7022 bytes	-1 byte	100%
10,000	7021 bytes	-1 byte	100%
100,000	7020 bytes	-1 byte	4.06%
1,000,000	7020 bytes	–	1.45%
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)	7067 bytes	+47 bytes (+0.67%)	+6 bytes
1	7068 bytes	+48 bytes (+0.68%)	+7 bytes
2	7061 bytes	+41 bytes (+0.58%)	–
3	7086 bytes	+66 bytes (+0.94%)	+25 bytes
4	7117 bytes	+97 bytes (+1.38%)	+56 bytes
5	7164 bytes	+144 bytes (+2.05%)	+103 bytes
6	7203 bytes	+183 bytes (+2.61%)	+142 bytes
7	7238 bytes	+218 bytes (+3.11%)	+177 bytes
8	7272 bytes	+252 bytes (+3.59%)	+211 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 - for example, your browser actually supports it !

Algorithm	Program	Parameters	Size	Compared To Best Zopfli
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	5888 bytes	-1132 bytes (-16.13%)
Brotli (Wikipedia)	brotli	brotli -q 11	6462 bytes	-558 bytes (-7.95%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	6657 bytes	-363 bytes (-5.17%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	6864 bytes	-156 bytes (-2.22%)
Zstandard (Wikipedia)	zstd	zstd -19	7037 bytes	+17 bytes (+0.24%)
LZMA2 (Wikipedia)	xz	xz -9	7040 bytes	+20 bytes (+0.28%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	7233 bytes	+213 bytes (+3.03%)

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 2026.
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.