Choose a version:
48% 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, direct link
Boot
  8684 bytes (8.5k)
CDN, direct link
MaxCDN
  8684 bytes (8.5k)
CDN, direct link
cdnjs
  7355 bytes (7.2k)
CDN, direct link
gzip -6 (default)
  7332 bytes (7.2k)
local copy
gzip -9
  7314 bytes (7.1k)
local copy
cdnhttps
  7309 bytes (7.1k)
CDN, direct link
Yandex
  7299 bytes (7.1k)
CDN, direct link
jsdelivr
  7299 bytes (7.1k)
CDN, direct link
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
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

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):
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 http://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 http://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)
cdnhttps 7309 bytes c2e5221c3336abe0dff8568e73cd0dae December 24, 2015 @ 07:36
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:

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 June 16, 2016 @ 14:40.

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
7029 7029 7037 7038 7037 7035 7035 7036 7035 7024 7025 7024 7021 7023 7023
7033 7033 7033 7033 7033 7034 7026 7024 7033 7026 7025 7027 7027 7026 7023
7024 7024 7024 7025 7025 7025 7026 7024 7030 7029 7025 7022 7024 7023 7022
7034 7034 7032 7033 7033 7024 7024 7023 7028 7026 7026 7023 7024 7023 7026
7033 7033 7029 7034 7033 7025 7024 7024 7028 7025 7025 7022 7022 7023 7023
7033 7033 7032 7032 7025 7025 7032 7024 7028 7025 7022 7023 7023 7023 7023
7033 7033 7032 7029 7026 7025 7025 7023 7029 7024 7024 7025 7024 7023 7023
7034 7034 7026 7035 7025 7024 7034 7024 7028 7025 7026 7024 7021 7023 7023
7034 7034 7032 7024 7025 7025 7034 7024 7028 7025 7026 7022 7026 7022 7025
7033 7033 7032 7034 7025 7024 7025 7024 7028 7029 7026 7023 7022 7023 7022
7033 7033 7025 7025 7025 7024 7033 7025 7025 7026 7026 7024 7022 7022 7023
7032 7032 7032 7032 7029 7025 7025 7023 7028 7025 7026 7023 7023 7023 7020
7034 7034 7032 7033 7025 7025 7025 7023 7028 7025 7025 7023 7026 7027 7023
7034 7034 7032 7033 7024 7024 7026 7026 7028 7025 7024 7023 7022 7022 7025
7033 7033 7032 7033 7024 7024 7025 7024 7028 7025 7026 7022 7021 7024 7020
7034 7034 7032 7033 7025 7025 7024 7025 7025 7021 7026 7024 7021 7026 7026
7033 7033 7024 7033 7034 7025 7025 7029 7025 7025 7026 7024 7024 7023 7022
7033 7033 7032 7033 7025 7024 7026 7024 7023 7025 7025 7024 7024 7023 7020
7024 7024 7032 7027 7024 7024 7024 7025 7028 7025 7024 7022 7021 7022 7020
7034 7034 7032 7033 7025 7033 7026 7025 7028 7025 7025 7026 7021 7023 7020
7034 7034 7032 7035 7025 7025 7024 7024 7028 7025 7026 7022 7021 7022 7023
7033 7033 7032 7034 7032 7034 7025 7024 7029 7025 7026 7024 7023 7022 7023
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
7067 bytes +47 bytes (+0.67%) +6 bytes
7068 bytes +48 bytes (+0.68%) +7 bytes
7061 bytes +41 bytes (+0.58%)
7086 bytes +66 bytes (+0.94%) +25 bytes
7117 bytes +97 bytes (+1.38%) +56 bytes
7164 bytes +144 bytes (+2.05%) +103 bytes
7203 bytes +183 bytes (+2.61%) +142 bytes
7238 bytes +218 bytes (+3.11%) +177 bytes
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.
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%)
ZSTD (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):


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