Choose a version:
24% The original file has 380250 bytes (371.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 91816 bytes (89.7k, 24%).

After GZIP compression these minified files vary in size:
Boot
  36002 bytes (35.2k)
CDN
cdnhttps
  31520 bytes (30.8k)
CDN
cdnjs
  31464 bytes (30.7k)
CDN
gzip -6 (default)
  31384 bytes (30.6k)
local copy
gzip -9
  31338 bytes (30.6k)
local copy
7zip -mx=9 -tgzip
  29930 bytes (29.2k)
local copy
libdeflate -12
  29911 bytes (29.2k)
local copy
kzip -s0 -rn -b3
  29902 bytes (29.2k)
local copy
pigz -11 -n
  29867 bytes (29.2k)
local copy
Zopfli
  29793 bytes (29.1k)
local copy
Zopfli (defluff)
  29792 bytes (29.1k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.6.2.min.js

You will automatically get the smallest Dojo 1.6.2 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 1671 bytes by using my Dojo 1.6.2 Zopfli version instead of the best available CDN (5.61% smaller than cdnjs, 29793 vs. 31464 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 --mls2 --bsr14 --lazy --ohh

(found December 2, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 2  --mls2
block splitting recursion 14  --bsr14
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

Even Smaller Files Thanks To Defluff

Zopfli's output can be further optimized by the defluff tool.
In this particular case, defluff saves 1 more byte (29792 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://download.dojotoolkit.org/release-1.6.2/dojo.js --location | md5sum
9c32244db56b10b248204603059dda8f  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.6.2.min.zopfli.js.gz | md5sum
9c32244db56b10b248204603059dda8f  -

SHA1:
curl --silent --compressed http://download.dojotoolkit.org/release-1.6.2/dojo.js --location | sha1sum
9f2f0352582bb2542823a1656420fdc89f622e9e  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.6.2.min.zopfli.js.gz | sha1sum
9f2f0352582bb2542823a1656420fdc89f622e9e  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 36002 bytes 9c32244db56b10b248204603059dda8f March 19, 2015 @ 15:33
cdnjs 31464 bytes 9c32244db56b10b248204603059dda8f February 8, 2015 @ 14:45

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 31520 bytes 2430575ef7742d7a3ad5c847cb15d530 < /*
< Copyright (c) 2004-2012, The Dojo Foundation All Rights R [...]
< Available via Academic Free License >= 2.1 OR the modifie [...]
< see: http://dojotoolkit.org/license for details
< */
<
< /*
< This is an optimized version of Dojo, built for deploymen [...]
< development. To get sources and documentation, please vis [...]
<
[...]
December 24, 2015 @ 07:33

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

Other Versions

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

1.13.0,
1.12.3, 1.12.2, 1.12.1,
1.11.5, 1.11.4, 1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.9, 1.10.8, 1.10.7, 1.10.6, 1.10.5, 1.10.4, 1.10.3, 1.10.2, 1.10.1, 1.10.0,
1.9.11, 1.9.10, 1.9.9, 1.9.8, 1.9.7, 1.9.6, 1.9.5, 1.9.4, 1.9.3, 1.9.2, 1.9.1, 1.9.0,
1.8.12, 1.8.11, 1.8.10, 1.8.9, 1.8.8, 1.8.7, 1.8.6, 1.8.5, 1.8.4, 1.8.3, 1.8.2, 1.8.1, 1.8.0,
1.7.10, 1.7.9, 1.7.8, 1.7.7, 1.7.6, 1.7.5, 1.7.4, 1.7.3, 1.7.2, 1.7.1, 1.7.0,
1.6.3, 1.6.2, 1.6.1, 1.6.0,
1.5.4, 1.5.3, 1.5.2, 1.5.1, 1.5.0,
1.4.6, 1.4.5, 1.4.4, 1.4.3, 1.4.2, 1.4.1, 1.4.0,
1.3.3, 1.3.2, 1.3.1, 1.3.0,
1.2.3

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

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
29793 bytes -2 bytes zopfli --i100000 --mls2 --bsr14 --lazy --ohh December 2, 2015 @ 11:23
29795 bytes -1 byte zopfli --i100000 --mls64 --bsr17 --lazy --ohh December 2, 2015 @ 10:45
29796 bytes -5 bytes zopfli --i10000 --mls64 --bsr17 --lazy --ohh November 22, 2015 @ 22:18
29801 bytes -6 bytes zopfli --i1000 --mls64 --bsr17 --lazy --ohh September 21, 2015 @ 05:19
29807 bytes -2 bytes zopfli --i1000 --mls8 --bsr20 --lazy --ohh September 20, 2015 @ 04:34
29809 bytes -3 bytes zopfli --i1000 --mls64 --bsr13 --lazy --ohh September 14, 2015 @ 16:30
29812 bytes -1 byte zopfli --i1000 --mls2048 --bsr8 --lazy --ohh September 10, 2015 @ 22:58
29813 bytes -4 bytes zopfli --i1000 --mls512 --bsr12 --lazy --ohh September 10, 2015 @ 22:53
29817 bytes -2 bytes zopfli --i1000 --mls512 --bsr10 --lazy --ohh September 10, 2015 @ 22:52
29819 bytes zopfli --i100 --mls2048 --bsr8 --lazy --ohh September 10, 2015 @ 15:18

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 @ 14:35.

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 or 100,000.
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
29832 29854 29842 29847 29845 29852 29866 29863 29869 29865 29870 29862 29874 29870 29864
29836 29838 29836 29836 29842 29854 29853 29852 29866 29853 29849 29862 29862 29866 29856
29814 29817 29813 29860 29826 29825 29853 29854 29820 29858 29854 29858 29863 29861 29861
29815 29819 29829 29828 29828 29831 29850 29852 29820 29857 29850 29844 29852 29854 29865
29813 29815 29806 29830 29839 29813 29860 29857 29835 29860 29808 29855 29864 29864 29865
29810 29805 29827 29836 29831 29843 29846 29853 29846 29858 29850 29854 29869 29853 29861
29820 29822 29821 29828 29834 29833 29859 29850 29812 29858 29856 29848 29854 29859 29852
29830 29826 29823 29841 29830 29829 29850 29855 29861 29858 29843 29862 29852 29860 29862
29810 29808 29810 29830 29824 29813 29850 29856 29809 29843 29843 29858 29861 29864 29854
29811 29828 29804 29823 29828 29804 29848 29850 29821 29843 29843 29852 29850 29853 29863
29793 29793 29815 29816 29820 29823 29850 29851 29818 29845 29843 29854 29853 29867 29862
29828 29793 29829 29817 29818 29822 29845 29843 29808 29846 29844 29869 29850 29867 29866
29803 29801 29812 29818 29827 29823 29847 29853 29845 29862 29851 29854 29866 29867 29863
29809 29821 29820 29835 29834 29795 29822 29853 29812 29858 29850 29855 29858 29867 29862
29826 29815 29835 29826 29828 29813 29849 29854 29825 29858 29849 29855 29853 29864 29862
29822 29805 29804 29817 29830 29812 29859 29855 29813 29859 29851 29855 29852 29853 29862
29807 29834 29803 29825 29829 29807 29855 29852 29828 29858 29810 29853 29866 29852 29861
29838 29808 29803 29824 29824 29839 29847 29850 29858 29858 29843 29855 29859 29869 29862
29833 29811 29812 29835 29825 29854 29825 29853 29828 29857 29851 29854 29853 29852 29863
29807 29810 29805 29828 29825 29839 29823 29855 29821 29859 29843 29855 29850 29852 29862
29834 29822 29826 29826 29828 29818 29828 29854 29822 29845 29844 29848 29870 29862 29853
29794 29822 29807 29831 29817 29829 29860 29856 29819 29844 29802 29854 29847 29850 29861
29806 29809 29805 29819 29827 29822 29848 29851 29822 29845 29803 29854 29853 29852 29868

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 29805 bytes 100%
1,000 29801 bytes -4 bytes 100%
10,000 29796 bytes -5 bytes 100%
100,000 29793 bytes -3 bytes 1.45%
1,000,000
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
29909 bytes +116 bytes (+0.39%) +7 bytes
29916 bytes +123 bytes (+0.41%) +14 bytes
29949 bytes +156 bytes (+0.52%) +47 bytes
29902 bytes +109 bytes (+0.37%)
29942 bytes +149 bytes (+0.50%) +40 bytes
29930 bytes +137 bytes (+0.46%) +28 bytes
29945 bytes +152 bytes (+0.51%) +43 bytes
29926 bytes +133 bytes (+0.45%) +24 bytes
29964 bytes +171 bytes (+0.57%) +62 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
ZPAQ (Wikipedia) zpaq zpaq -method 69 23522 bytes -6271 bytes (-21.05%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 26437 bytes -3356 bytes (-11.26%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 27435 bytes -2358 bytes (-7.91%)
Brotli (Wikipedia) brotli brotli -q 11 27541 bytes -2252 bytes (-7.56%)
LZMA2 (Wikipedia) xz xz -9 28460 bytes -1333 bytes (-4.47%)
ZSTD (Wikipedia) zstd zstd -19 29253 bytes -540 bytes (-1.81%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 29326 bytes -467 bytes (-1.57%)

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):


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 2018.
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