Choose a version:
26% The original file has 599370 bytes (585.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 156515 bytes (152.8k, 26%).

After GZIP compression these minified files vary in size:
Boot
  62005 bytes (60.6k)
CDN
cdnhttps
  53888 bytes (52.6k)
CDN
Baidu
  53788 bytes (52.5k)
CDN
cdnjs
  53781 bytes (52.5k)
CDN
gzip -6 (default)
  53543 bytes (52.3k)
local copy
gzip -9
  53478 bytes (52.2k)
local copy
libdeflate -12
  51007 bytes (49.8k)
local copy
7zip -mx=9 -tgzip
  50943 bytes (49.7k)
local copy
kzip -s0 -rn -b1
  50870 bytes (49.7k)
local copy
pigz -11 -n
  50865 bytes (49.7k)
local copy
Zopfli
  50725 bytes (49.5k)
local copy
Zopfli (defluff)
  50723 bytes (49.5k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.8.2.min.js

You will automatically get the smallest Dojo 1.8.2 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 3056 bytes by using my Dojo 1.8.2 Zopfli version instead of the best available CDN (6.02% smaller than cdnjs, 50725 vs. 53781 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 --mls8 --bsr12 --lazy --ohh

(found December 3, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 8  --mls8
block splitting recursion 12  --bsr12
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 2 more bytes (50723 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://download.dojotoolkit.org/release-1.8.2/dojo.js --location | md5sum
2e31d09a6207980e63b514527a89d341  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.8.2.min.zopfli.js.gz | md5sum
2e31d09a6207980e63b514527a89d341  -

SHA1:
curl --silent --compressed http://download.dojotoolkit.org/release-1.8.2/dojo.js --location | sha1sum
570b8f4f43022cef7860db8d57ed2d0dd1dad2eb  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.8.2.min.zopfli.js.gz | sha1sum
570b8f4f43022cef7860db8d57ed2d0dd1dad2eb  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 62005 bytes 2e31d09a6207980e63b514527a89d341 March 19, 2015 @ 15:38
cdnjs 53781 bytes 2e31d09a6207980e63b514527a89d341 February 8, 2015 @ 14:45

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 53888 bytes 996109a1fc78505f55fa1bae84d27b39 < /*
< 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
Baidu 53788 bytes 0117df810f2665a00f2cc5c3764df595 only whitespaces differ January 7, 2015 @ 10:16

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
50725 bytes -1 byte zopfli --i100000 --mls8 --bsr12 --lazy --ohh December 3, 2015 @ 11:04
50726 bytes -3 bytes zopfli --i10000 --mls8 --bsr12 --lazy --ohh October 14, 2015 @ 01:49
50729 bytes -25 bytes zopfli --i1000 --mls8 --bsr12 --lazy --ohh September 19, 2015 @ 15:44
50754 bytes zopfli --i100 --mls8 --bsr12 --lazy --ohh September 18, 2015 @ 16:15

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 @ 14:38.

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
50766 50766 50767 50769 50770 50767 50767 50775 50768 50772 50770 50790 50800 50786 50764
50773 50767 50768 50762 50770 50774 50774 50770 50775 50765 50768 50790 50771 50772 50772
50765 50767 50765 50763 50779 50774 50766 50772 50776 50784 50789 50786 50793 50795 50766
50762 50775 50763 50769 50761 50763 50772 50772 50786 50766 50769 50792 50797 50767 50770
50764 50764 50768 50771 50763 50772 50771 50775 50783 50791 50780 50776 50787 50781 50769
50764 50771 50764 50763 50785 50770 50770 50777 50764 50763 50764 50785 50788 50783 50769
50761 50764 50765 50769 50765 50771 50772 50773 50766 50766 50777 50785 50787 50773 50769
50763 50763 50783 50762 50783 50774 50771 50770 50780 50769 50767 50785 50776 50767 50769
50762 50765 50725 50762 50784 50774 50772 50773 50766 50760 50773 50785 50788 50763 50769
50772 50765 50768 50760 50763 50772 50772 50770 50767 50765 50776 50786 50783 50781 50769
50761 50787 50785 50760 50783 50772 50776 50772 50768 50765 50768 50779 50783 50775 50770
50766 50762 50763 50790 50763 50763 50771 50773 50781 50763 50763 50786 50787 50773 50769
50762 50762 50764 50785 50763 50782 50776 50769 50765 50764 50766 50785 50792 50776 50769
50763 50765 50767 50773 50761 50771 50769 50780 50766 50764 50766 50785 50789 50769 50769
50763 50762 50767 50765 50769 50763 50772 50771 50765 50772 50766 50785 50786 50774 50769
50763 50766 50764 50770 50783 50782 50773 50769 50767 50762 50767 50786 50786 50772 50762
50762 50765 50764 50763 50763 50763 50775 50766 50767 50771 50777 50785 50787 50767 50769
50761 50765 50764 50765 50763 50764 50769 50772 50770 50785 50779 50785 50789 50767 50769
50762 50765 50768 50764 50786 50772 50770 50770 50770 50771 50776 50785 50786 50783 50769
50763 50764 50767 50769 50765 50771 50772 50772 50770 50767 50776 50785 50789 50762 50769
50770 50763 50767 50786 50763 50771 50771 50770 50770 50764 50767 50784 50787 50781 50769
50763 50763 50768 50761 50781 50770 50764 50769 50766 50784 50766 50785 50790 50769 50770
50761 50764 50764 50761 50763 50763 50771 50769 50767 50766 50767 50787 50787 50776 50770

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 50754 bytes 100%
1,000 50729 bytes -25 bytes 100%
10,000 50726 bytes -3 bytes 100%
100,000 50725 bytes -1 byte 0.29%
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
50914 bytes +189 bytes (+0.37%) +44 bytes
50870 bytes +145 bytes (+0.29%)
50884 bytes +159 bytes (+0.31%) +14 bytes
50910 bytes +185 bytes (+0.36%) +40 bytes
50960 bytes +235 bytes (+0.46%) +90 bytes
50983 bytes +258 bytes (+0.51%) +113 bytes
50993 bytes +268 bytes (+0.53%) +123 bytes
51016 bytes +291 bytes (+0.57%) +146 bytes
51019 bytes +294 bytes (+0.58%) +149 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 37340 bytes -13385 bytes (-26.39%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 44198 bytes -6527 bytes (-12.87%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 45483 bytes -5242 bytes (-10.33%)
Brotli (Wikipedia) brotli brotli -q 11 46636 bytes -4089 bytes (-8.06%)
LZMA2 (Wikipedia) xz xz -9 47732 bytes -2993 bytes (-5.90%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 49126 bytes -1599 bytes (-3.15%)
ZSTD (Wikipedia) zstd zstd -19 49183 bytes -1542 bytes (-3.04%)

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