Choose a version:
47% The original file has 58458 bytes (57.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 27726 bytes (27.1k, 47%).

After GZIP compression these minified files vary in size:
Microsoft
  9452 bytes (9.2k)
CDN, direct link
Boot
  8632 bytes (8.4k)
CDN, direct link
MaxCDN
  8632 bytes (8.4k)
CDN, direct link
cdnjs
  7300 bytes (7.1k)
CDN, direct link
gzip -6 (default)
  7275 bytes (7.1k)
local copy
gzip -9
  7258 bytes (7.1k)
local copy
Sina
  7252 bytes (7.1k)
CDN, direct link
cdnhttps
  7252 bytes (7.1k)
CDN, direct link
Yandex
  7242 bytes (7.1k)
CDN, direct link
jsdelivr
  7242 bytes (7.1k)
CDN, direct link
7zip -mx=9 -tgzip
  7018 bytes (6.9k)
local copy
libdeflate -12
  7018 bytes (6.9k)
local copy
kzip -s0 -rn -b0
  7010 bytes (6.8k)
local copy
pigz -11 -n
  6974 bytes (6.8k)
local copy
Zopfli
  6967 bytes (6.8k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.0.min.js

You will automatically get the smallest Bootstrap 3.0.0 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

Save 275 bytes by using my Bootstrap 3.0.0 Zopfli version instead of the best available CDN (3.95% smaller than jsdelivr, 6967 vs. 7242 bytes):
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 --mls2048 --bsr9 --lazy --ohh

(found December 1, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 2048  --mls2048
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/v3.0.0/dist/js/bootstrap.min.js --location | md5sum
9e25e8e29ef0ea358e9778082ffd97d8  -
curl --silent --compressed http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.0.min.zopfli.js.gz | md5sum
9e25e8e29ef0ea358e9778082ffd97d8  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/twbs/bootstrap/v3.0.0/dist/js/bootstrap.min.js --location | sha1sum
75a42212affc118fef849aba4b9326a7da2acda1  -
curl --silent --compressed http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.0.min.zopfli.js.gz | sha1sum
75a42212affc118fef849aba4b9326a7da2acda1  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Microsoft 9452 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)
Boot 8632 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)
MaxCDN 8632 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)
cdnjs 7300 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)
Sina 7252 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)
cdnhttps 7252 bytes 9e25e8e29ef0ea358e9778082ffd97d8 December 24, 2015 @ 07:36
Yandex 7242 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)
jsdelivr 7242 bytes 9e25e8e29ef0ea358e9778082ffd97d8 (invalid)

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

Other Versions

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

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
6967 bytes -1 byte zopfli --i100000 --mls2048 --bsr9 --lazy --ohh December 1, 2015 @ 10:07
6968 bytes -2 bytes zopfli --i1000 --mls2048 --bsr14 --lazy --ohh September 10, 2015 @ 16:55
6970 bytes zopfli --i100 --mls512 --bsr16 --lazy --ohh September 10, 2015 @ 16:29

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

Most recent activity on June 16, 2016 @ 14:37.

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
6982 6982 6982 6982 6982 6983 6983 6982 6976 6972 6973 6972 6972 6972 6972
6976 6976 6979 6971 6971 6970 6976 6971 6972 6972 6971 6974 6973 6973 6973
6976 6976 6970 6977 6975 6970 6975 6969 6971 6973 6978 6971 6971 6969 6971
6976 6976 6970 6974 6975 6970 6976 6971 6971 6970 6972 6971 6971 6971 6971
6970 6970 6970 6970 6975 6971 6976 6970 6975 6971 6970 6971 6969 6968 6971
6971 6971 6970 6970 6975 6970 6971 6971 6970 6971 6967 6971 6971 6971 6971
6970 6970 6970 6970 6971 6970 6976 6971 6972 6973 6972 6971 6971 6969 6972
6975 6975 6971 6971 6970 6970 6970 6970 6971 6969 6972 6970 6968 6969 6971
6970 6970 6970 6970 6971 6975 6970 6970 6970 6973 6972 6971 6969 6969 6971
6979 6979 6970 6970 6970 6970 6970 6971 6975 6973 6977 6971 6969 6974 6971
6970 6970 6971 6975 6974 6970 6970 6969 6971 6971 6968 6970 6969 6969 6971
6975 6975 6971 6970 6975 6970 6971 6971 6971 6973 6972 6972 6970 6971 6971
6970 6970 6976 6970 6971 6970 6971 6971 6968 6973 6972 6971 6969 6971 6971
6976 6976 6971 6971 6971 6972 6971 6970 6971 6968 6973 6971 6971 6968 6971
6971 6971 6970 6971 6970 6970 6971 6970 6975 6970 6971 6971 6971 6971 6971
6970 6970 6970 6970 6972 6970 6971 6971 6969 6969 6972 6971 6971 6971 6971
6971 6971 6970 6975 6972 6970 6975 6971 6976 6970 6974 6971 6971 6969 6971
6976 6976 6970 6970 6971 6970 6976 6971 6971 6973 6970 6972 6969 6968 6971
6976 6976 6970 6970 6975 6971 6970 6971 6975 6970 6972 6971 6969 6969 6971
6970 6970 6970 6970 6970 6970 6976 6971 6969 6970 6972 6971 6972 6971 6971
6970 6970 6970 6970 6971 6970 6970 6970 6971 6973 6972 6971 6969 6969 6971
6970 6970 6971 6971 6971 6971 6972 6971 6971 6970 6967 6970 6969 6968 6971
6970 6970 6971 6972 6972 6970 6972 6970 6971 6972 6972 6971 6968 6971 6971

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 6970 bytes 100%
1,000 6968 bytes -2 bytes 100%
10,000 6968 bytes 100%
100,000 6967 bytes -1 byte 3.19%
1,000,000 6967 bytes 0.58%
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
7010 bytes +43 bytes (+0.62%)
7010 bytes +43 bytes (+0.62%)
7022 bytes +55 bytes (+0.79%) +12 bytes
7032 bytes +65 bytes (+0.93%) +22 bytes
7063 bytes +96 bytes (+1.38%) +53 bytes
7111 bytes +144 bytes (+2.07%) +101 bytes
7153 bytes +186 bytes (+2.67%) +143 bytes
7186 bytes +219 bytes (+3.14%) +176 bytes
7219 bytes +252 bytes (+3.62%) +209 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
Algorithm Program Parameters Size Compared To Best Zopfli
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 5836 bytes -1131 bytes (-16.23%)
Brotli (Wikipedia) brotli brotli -q 11 6428 bytes -539 bytes (-7.74%)
ZPAQ (Wikipedia) zpaq zpaq -method 69 6602 bytes -365 bytes (-5.24%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 6812 bytes -155 bytes (-2.22%)
ZSTD (Wikipedia) zstd zstd -19 6981 bytes +14 bytes (+0.20%)
LZMA2 (Wikipedia) xz xz -9 6984 bytes +17 bytes (+0.24%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 7192 bytes +225 bytes (+3.23%)

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):


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 2017.
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