Choose a version:
48% The original file has 58411 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 27832 bytes (27.2k, 48%).

After GZIP compression these minified files vary in size:
Microsoft
  9512 bytes (9.3k)
CDN, direct link
Boot
  8692 bytes (8.5k)
CDN, direct link
MaxCDN
  8692 bytes (8.5k)
CDN, direct link
cdnjs
  7358 bytes (7.2k)
CDN, direct link
gzip -6 (default)
  7335 bytes (7.2k)
local copy
gzip -9
  7317 bytes (7.1k)
local copy
cdnhttps
  7312 bytes (7.1k)
CDN, direct link
Yandex
  7301 bytes (7.1k)
CDN, direct link
jsdelivr
  7301 bytes (7.1k)
CDN, direct link
7zip -mx=9 -tgzip
  7079 bytes (6.9k)
local copy
libdeflate -12
  7076 bytes (6.9k)
local copy
kzip -s0 -rn -b2
  7063 bytes (6.9k)
local copy
pigz -11 -n
  7026 bytes (6.9k)
local copy
Zopfli
  7021 bytes (6.9k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.1.min.js

You will automatically get the smallest Bootstrap 3.0.1 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 280 bytes by using my Bootstrap 3.0.1 Zopfli version instead of the best available CDN (3.99% smaller than jsdelivr, 7021 vs. 7301 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 --i10000 --mb8 --mls512 --bsr9 --lazy --ohh

(found September 10, 2015)
Description Value Parameter
iterations 10000  --i10000
maximum blocks 8  --mb8
maximum length score 512  --mls512
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/v3.0.1/dist/js/bootstrap.min.js --location | md5sum
d6834e94301cc3ab9cc013574d092b61  -
curl --silent --compressed http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.1.min.zopfli.js.gz | md5sum
d6834e94301cc3ab9cc013574d092b61  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/twbs/bootstrap/v3.0.1/dist/js/bootstrap.min.js --location | sha1sum
0656f0d8f62bc0bbc2a745e0dc4dcc4213db4ed8  -
curl --silent --compressed http://minime.stephan-brumme.com/files/bootstrap/bootstrap-3.0.1.min.zopfli.js.gz | sha1sum
0656f0d8f62bc0bbc2a745e0dc4dcc4213db4ed8  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Microsoft 9512 bytes d6834e94301cc3ab9cc013574d092b61 (invalid)
Boot 8692 bytes d6834e94301cc3ab9cc013574d092b61 (invalid)
MaxCDN 8692 bytes d6834e94301cc3ab9cc013574d092b61 (invalid)
cdnjs 7358 bytes d6834e94301cc3ab9cc013574d092b61 (invalid)
cdnhttps 7312 bytes d6834e94301cc3ab9cc013574d092b61 December 24, 2015 @ 07:36
Yandex 7301 bytes d6834e94301cc3ab9cc013574d092b61 (invalid)
jsdelivr 7301 bytes d6834e94301cc3ab9cc013574d092b61 (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
7021 bytes -2 bytes zopfli --i10000 --mls512 --bsr9 --lazy --ohh September 10, 2015 @ 19:47
7023 bytes -1 byte zopfli --i1000 --mls512 --bsr11 --lazy --ohh September 10, 2015 @ 16:53
7024 bytes zopfli --i100 --mls512 --bsr16 --lazy --ohh September 10, 2015 @ 16:28

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 @ 14:41.

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
7031 7031 7038 7031 7031 7031 7031 7031 7027 7026 7029 7024 7024 7025 7025
7037 7037 7036 7031 7027 7027 7023 7026 7028 7028 7027 7025 7027 7025 7025
7027 7027 7028 7027 7027 7029 7030 7025 7024 7029 7029 7024 7026 7023 7029
7027 7027 7027 7032 7027 7031 7028 7026 7021 7027 7026 7025 7025 7025 7026
7031 7031 7027 7031 7027 7026 7030 7025 7021 7024 7030 7024 7024 7025 7026
7031 7031 7031 7032 7031 7026 7028 7025 7021 7028 7027 7024 7025 7025 7025
7031 7031 7031 7031 7027 7028 7028 7026 7027 7023 7026 7027 7026 7025 7027
7030 7030 7027 7026 7027 7027 7027 7025 7023 7026 7029 7024 7026 7024 7025
7035 7035 7027 7026 7027 7027 7026 7025 7021 7026 7029 7026 7026 7026 7026
7035 7035 7035 7031 7031 7028 7027 7025 7027 7024 7029 7027 7026 7024 7025
7028 7028 7026 7026 7028 7027 7028 7025 7025 7027 7029 7027 7025 7024 7025
7036 7036 7026 7031 7027 7031 7022 7026 7027 7023 7029 7024 7024 7026 7026
7029 7029 7029 7026 7027 7026 7028 7026 7023 7027 7027 7027 7026 7025 7025
7035 7035 7030 7027 7027 7027 7028 7026 7027 7024 7023 7024 7026 7024 7026
7035 7035 7027 7031 7031 7025 7027 7023 7031 7023 7026 7025 7025 7024 7027
7030 7030 7027 7026 7028 7027 7028 7026 7023 7023 7027 7027 7026 7025 7024
7031 7031 7030 7026 7027 7028 7027 7025 7030 7023 7029 7027 7026 7024 7026
7035 7035 7027 7024 7027 7027 7027 7025 7021 7024 7026 7027 7026 7025 7026
7031 7031 7027 7026 7027 7027 7027 7025 7024 7023 7027 7024 7026 7025 7026
7031 7031 7027 7026 7027 7027 7027 7025 7021 7026 7027 7024 7024 7026 7024
7031 7031 7026 7026 7027 7027 7027 7025 7027 7026 7026 7024 7026 7024 7027
7031 7031 7026 7026 7027 7028 7028 7025 7023 7023 7026 7027 7024 7024 7024
7030 7030 7031 7026 7027 7027 7028 7025 7021 7027 7029 7024 7026 7025 7024

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 7024 bytes 100%
1,000 7023 bytes -1 byte 100%
10,000 7021 bytes -2 bytes 100%
100,000 7021 bytes 2.32%
1,000,000 7021 bytes 2.03%
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
7069 bytes +48 bytes (+0.68%) +6 bytes
7070 bytes +49 bytes (+0.70%) +7 bytes
7063 bytes +42 bytes (+0.60%)
7088 bytes +67 bytes (+0.95%) +25 bytes
7119 bytes +98 bytes (+1.40%) +56 bytes
7166 bytes +145 bytes (+2.07%) +103 bytes
7208 bytes +187 bytes (+2.66%) +145 bytes
7241 bytes +220 bytes (+3.13%) +178 bytes
7275 bytes +254 bytes (+3.62%) +212 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 5890 bytes -1131 bytes (-16.11%)
Brotli (Wikipedia) brotli brotli -q 11 6463 bytes -558 bytes (-7.95%)
ZPAQ (Wikipedia) zpaq zpaq -method 69 6657 bytes -364 bytes (-5.18%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 6870 bytes -151 bytes (-2.15%)
LZMA2 (Wikipedia) xz xz -9 7036 bytes +15 bytes (+0.21%)
ZSTD (Wikipedia) zstd zstd -19 7036 bytes +15 bytes (+0.21%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 7238 bytes +217 bytes (+3.09%)

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