Choose a version:
26% The original file has 597748 bytes (583.7k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 155966 bytes (152.3k, 26%).

After GZIP compression these minified files vary in size:
Boot
  61747 bytes (60.3k)
CDN
cdnhttps
  53670 bytes (52.4k)
CDN
Baidu
  53568 bytes (52.3k)
CDN
cdnjs
  53561 bytes (52.3k)
CDN
gzip -6 (default)
  53313 bytes (52.1k)
local copy
gzip -9
  53254 bytes (52.0k)
local copy
Yandex
  53242 bytes (52.0k)
CDN
libdeflate -12
  50777 bytes (49.6k)
local copy
7zip -mx=9 -tgzip
  50756 bytes (49.6k)
local copy
kzip -s0 -rn -b1
  50686 bytes (49.5k)
local copy
pigz -11 -n
  50674 bytes (49.5k)
local copy
Zopfli
  50512 bytes (49.3k)
local copy
Zopfli (defluff)
  50511 bytes (49.3k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.8.0.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.8.0 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 2730 bytes by using my Dojo 1.8.0 Zopfli version instead of the best available CDN (5.40% smaller than Yandex, 50512 vs. 53242 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 --bsr4 --lazy --ohh

(found December 3, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 2  --mls2
block splitting recursion 4  --bsr4
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 (50511 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.8.0/dojo.js --location | md5sum
65666ba02155ec0cb55452cf8422dc31  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.8.0.min.zopfli.js.gz | md5sum
65666ba02155ec0cb55452cf8422dc31  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.8.0/dojo.js --location | sha1sum
4d13d6616235c683ce587724d9afda978033449f  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.8.0.min.zopfli.js.gz | sha1sum
4d13d6616235c683ce587724d9afda978033449f  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 61747 bytes 65666ba02155ec0cb55452cf8422dc31 March 19, 2015 @ 15:36
cdnjs 53561 bytes 65666ba02155ec0cb55452cf8422dc31 February 8, 2015 @ 14:45

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 53670 bytes 2e1262ba7275578939f023cdda238bca < /*
< Copyright (c) 2004-2011, 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 53568 bytes b8ab51dc9c7792d102bd1957da5d106e only whitespaces differ January 7, 2015 @ 10:16
Yandex 53242 bytes 0e3b3c81adffcf5a26d9b375db055dee < (function(_1,_2){var _3=function(){},_4=function(it){for(v [...]
> (function(_1,_2){var _3=function(){},_4=function(it){for(v [...]
June 20, 2013 @ 11:59

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
50512 bytes -6 bytes zopfli --i100000 --mls2 --bsr4 --lazy --ohh December 3, 2015 @ 11:01
50518 bytes -2 bytes zopfli --i10000 --mls2 --bsr4 --lazy --ohh October 14, 2015 @ 04:14
50520 bytes -7 bytes zopfli --i1000 --mls2 --bsr4 --lazy --ohh September 23, 2015 @ 06:41
50527 bytes -5 bytes zopfli --i1000 --mls4 --bsr4 --lazy --ohh September 21, 2015 @ 22:13
50532 bytes zopfli --i100 --mls4 --bsr4 --lazy --ohh September 21, 2015 @ 13:14

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 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
50577 50540 50535 50578 50577 50577 50579 50577 50584 50606 50604 50601 50597 50606 50576
50512 50524 50537 50573 50570 50583 50579 50584 50578 50577 50600 50577 50584 50581 50578
50556 50543 50537 50573 50584 50586 50573 50586 50578 50570 50589 50583 50600 50594 50574
50532 50593 50590 50545 50574 50582 50577 50574 50577 50577 50597 50577 50599 50586 50602
50611 50547 50557 50573 50571 50581 50577 50582 50577 50572 50600 50586 50598 50597 50620
50548 50574 50534 50572 50572 50573 50576 50574 50577 50571 50596 50596 50600 50598 50574
50543 50533 50540 50541 50575 50595 50576 50574 50577 50585 50587 50602 50604 50594 50574
50539 50528 50596 50573 50574 50582 50577 50575 50577 50578 50586 50602 50601 50583 50603
50552 50527 50529 50573 50574 50575 50575 50577 50577 50573 50584 50581 50599 50574 50582
50534 50529 50531 50573 50573 50575 50576 50578 50578 50591 50589 50582 50600 50604 50574
50540 50529 50550 50573 50572 50575 50575 50574 50577 50572 50589 50600 50601 50569 50579
50568 50526 50532 50574 50573 50574 50577 50579 50579 50572 50588 50581 50606 50579 50602
50531 50532 50532 50540 50573 50574 50575 50574 50577 50572 50589 50583 50600 50569 50599
50535 50530 50539 50541 50573 50573 50574 50574 50577 50575 50588 50582 50604 50591 50601
50532 50544 50542 50576 50575 50574 50578 50575 50581 50571 50588 50599 50603 50570 50599
50574 50537 50574 50574 50574 50573 50575 50578 50577 50570 50589 50602 50600 50574 50574
50539 50532 50539 50575 50572 50574 50576 50583 50577 50571 50585 50576 50599 50595 50602
50574 50532 50538 50574 50572 50574 50575 50578 50577 50571 50593 50584 50600 50578 50576
50533 50540 50538 50574 50574 50578 50574 50583 50576 50569 50583 50597 50604 50597 50574
50531 50533 50536 50574 50574 50578 50575 50575 50578 50574 50584 50600 50601 50575 50602
50570 50530 50532 50572 50574 50596 50573 50578 50577 50573 50583 50602 50599 50573 50602
50568 50576 50536 50572 50575 50574 50575 50581 50575 50575 50589 50596 50602 50590 50573
50540 50532 50540 50574 50573 50574 50575 50574 50578 50577 50586 50597 50601 50575 50574

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 50532 bytes 100%
1,000 50520 bytes -12 bytes 100%
10,000 50518 bytes -2 bytes 100%
100,000 50512 bytes -6 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
50721 bytes +209 bytes (+0.41%) +35 bytes
50686 bytes +174 bytes (+0.34%)
50698 bytes +186 bytes (+0.37%) +12 bytes
50729 bytes +217 bytes (+0.43%) +43 bytes
50766 bytes +254 bytes (+0.50%) +80 bytes
50791 bytes +279 bytes (+0.55%) +105 bytes
50773 bytes +261 bytes (+0.52%) +87 bytes
50786 bytes +274 bytes (+0.54%) +100 bytes
50773 bytes +261 bytes (+0.52%) +87 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 37236 bytes -13276 bytes (-26.28%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 44077 bytes -6435 bytes (-12.74%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 45386 bytes -5126 bytes (-10.15%)
Brotli (Wikipedia) brotli brotli -q 11 46452 bytes -4060 bytes (-8.04%)
LZMA2 (Wikipedia) xz xz -9 47544 bytes -2968 bytes (-5.88%)
Zstandard (Wikipedia) zstd zstd -19 48994 bytes -1518 bytes (-3.01%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 49010 bytes -1502 bytes (-2.97%)

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