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
  62006 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
jsdelivr
  53459 bytes (52.2k)
CDN
libdeflate -12
  51008 bytes (49.8k)
local copy
7zip -mx=9 -tgzip
  50943 bytes (49.7k)
local copy
kzip -s0 -rn -b1
  50869 bytes (49.7k)
local copy
pigz -11 -n
  50864 bytes (49.7k)
local copy
Zopfli
  50720 bytes (49.5k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.8.3.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.8.3 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 2739 bytes by using my Dojo 1.8.3 Zopfli version instead of the best available CDN (5.40% smaller than jsdelivr, 50720 vs. 53459 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

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.8.3/dojo.js --location | md5sum
8ccabd6905914220d1b4e0ae0a046ce6  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.8.3.min.zopfli.js.gz | md5sum
8ccabd6905914220d1b4e0ae0a046ce6  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.8.3/dojo.js --location | sha1sum
9708d9b0ac658f0af0776bebe492da030d8226ae  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.8.3.min.zopfli.js.gz | sha1sum
9708d9b0ac658f0af0776bebe492da030d8226ae  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 62006 bytes 8ccabd6905914220d1b4e0ae0a046ce6 March 19, 2015 @ 15:38
cdnjs 53781 bytes 8ccabd6905914220d1b4e0ae0a046ce6 February 8, 2015 @ 14:45
jsdelivr 53459 bytes 8ccabd6905914220d1b4e0ae0a046ce6 August 7, 2014 @ 19:16

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 53888 bytes 19a9be88a2d1c581e4c7ee601edd1ebb < /*
< 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 c7bb63f91f8f85b7831a046cb8458b7f 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:

1.14.2, 1.14.1, 1.14.0,
1.13.3, 1.13.2, 1.13.1, 1.13.0,
1.12.4, 1.12.3, 1.12.2, 1.12.1,
1.11.6, 1.11.5, 1.11.4, 1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.10, 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,
1.8.14, 1.8.13, 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,
1.7.12, 1.7.11, 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
50720 bytes -5 bytes zopfli --i100000 --mls8 --bsr12 --lazy --ohh December 3, 2015 @ 11:05
50725 bytes -4 bytes zopfli --i10000 --mls8 --bsr12 --lazy --ohh October 21, 2015 @ 13:41
50729 bytes -7 bytes zopfli --i1000 --mls8 --bsr12 --lazy --ohh September 19, 2015 @ 14:44
50736 bytes zopfli --i100 --mls8 --bsr12 --lazy --ohh September 18, 2015 @ 16:16

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 @ 14:39.

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
50767 50766 50768 50769 50770 50766 50767 50775 50769 50772 50770 50790 50801 50786 50764
50774 50767 50767 50762 50770 50773 50775 50770 50775 50765 50768 50789 50772 50772 50772
50765 50767 50765 50764 50779 50774 50766 50772 50777 50784 50791 50787 50793 50794 50766
50762 50775 50762 50770 50761 50763 50771 50772 50786 50767 50768 50792 50797 50767 50770
50764 50764 50768 50786 50763 50771 50771 50775 50782 50792 50779 50776 50786 50780 50769
50764 50771 50764 50764 50784 50770 50770 50776 50764 50762 50764 50785 50786 50782 50769
50761 50765 50765 50791 50765 50771 50771 50773 50766 50766 50777 50787 50791 50773 50769
50763 50764 50777 50762 50783 50774 50771 50770 50780 50769 50767 50785 50775 50766 50769
50762 50765 50720 50762 50788 50774 50771 50773 50768 50759 50772 50785 50790 50762 50769
50772 50766 50768 50760 50763 50772 50771 50770 50767 50766 50776 50786 50783 50780 50769
50761 50764 50788 50760 50783 50772 50776 50772 50769 50765 50767 50780 50783 50775 50769
50766 50762 50763 50788 50763 50764 50771 50773 50781 50763 50763 50786 50787 50773 50769
50763 50762 50763 50784 50763 50782 50776 50769 50766 50763 50766 50785 50792 50775 50769
50763 50765 50767 50770 50762 50771 50769 50780 50766 50763 50766 50785 50789 50769 50769
50763 50762 50767 50765 50770 50763 50771 50771 50765 50772 50766 50787 50791 50774 50769
50764 50766 50764 50769 50783 50781 50773 50769 50767 50762 50766 50787 50786 50772 50762
50763 50765 50764 50764 50763 50763 50775 50766 50767 50770 50777 50785 50786 50767 50769
50761 50765 50764 50764 50763 50764 50769 50772 50770 50785 50779 50785 50790 50767 50769
50762 50765 50767 50764 50786 50772 50770 50771 50770 50771 50776 50787 50786 50782 50769
50763 50764 50767 50769 50765 50771 50771 50772 50770 50767 50776 50785 50789 50761 50769
50770 50763 50767 50789 50763 50771 50770 50769 50770 50764 50767 50785 50788 50781 50770
50763 50764 50768 50761 50781 50769 50764 50770 50766 50784 50766 50786 50790 50769 50769
50761 50764 50764 50761 50763 50763 50771 50770 50767 50766 50767 50787 50786 50777 50769

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 50736 bytes 100%
1,000 50729 bytes -7 bytes 100%
10,000 50725 bytes -4 bytes 100%
100,000 50720 bytes -5 bytes 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
50908 bytes +188 bytes (+0.37%) +39 bytes
50869 bytes +149 bytes (+0.29%)
50887 bytes +167 bytes (+0.33%) +18 bytes
50916 bytes +196 bytes (+0.39%) +47 bytes
50956 bytes +236 bytes (+0.47%) +87 bytes
50986 bytes +266 bytes (+0.52%) +117 bytes
50995 bytes +275 bytes (+0.54%) +126 bytes
51015 bytes +295 bytes (+0.58%) +146 bytes
51014 bytes +294 bytes (+0.58%) +145 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
However, support for Brotli is constantly growing - but your browser doesn't support it.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 37341 bytes -13379 bytes (-26.38%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 44198 bytes -6522 bytes (-12.86%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 45482 bytes -5238 bytes (-10.33%)
Brotli (Wikipedia) brotli brotli -q 11 46641 bytes -4079 bytes (-8.04%)
LZMA2 (Wikipedia) xz xz -9 47732 bytes -2988 bytes (-5.89%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 49053 bytes -1667 bytes (-3.29%)
Zstandard (Wikipedia) zstd zstd -19 49182 bytes -1538 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 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