Choose a version:
24% The original file has 377390 bytes (368.5k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 90277 bytes (88.2k, 24%).

After GZIP compression these minified files vary in size:
Boot
  35397 bytes (34.6k)
CDN, direct link
cdnhttps
  30971 bytes (30.2k)
CDN, direct link
Baidu
  30915 bytes (30.2k)
CDN, direct link
cdnjs
  30907 bytes (30.2k)
CDN, direct link
gzip -6 (default)
  30820 bytes (30.1k)
local copy
gzip -9
  30793 bytes (30.1k)
local copy
Yandex
  30773 bytes (30.1k)
CDN, direct link
libdeflate -12
  29422 bytes (28.7k)
local copy
7zip -mx=9 -tgzip
  29404 bytes (28.7k)
local copy
kzip -s0 -rn -b1
  29386 bytes (28.7k)
local copy
pigz -11 -n
  29355 bytes (28.7k)
local copy
Zopfli
  29265 bytes (28.6k)
local copy
Zopfli (defluff)
  29264 bytes (28.6k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.5.0.min.js

You will automatically get the smallest Dojo 1.5.0 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 1508 bytes by using my Dojo 1.5.0 Zopfli version instead of the best available CDN (5.15% smaller than Yandex, 29265 vs. 30773 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 --bsr22 --lazy --ohh

(found December 2, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 8  --mls8
block splitting recursion 22  --bsr22
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 (29264 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://download.dojotoolkit.org/release-1.5.0/dojo.js --location | md5sum
b212742b08f37af01790b45b6190b16e  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.5.0.min.zopfli.js.gz | md5sum
b212742b08f37af01790b45b6190b16e  -

SHA1:
curl --silent --compressed http://download.dojotoolkit.org/release-1.5.0/dojo.js --location | sha1sum
5a049c7e19a26a6aa96a2bdcb19ea36ec868f56d  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.5.0.min.zopfli.js.gz | sha1sum
5a049c7e19a26a6aa96a2bdcb19ea36ec868f56d  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 35397 bytes b212742b08f37af01790b45b6190b16e March 19, 2015 @ 15:31
cdnjs 30907 bytes b212742b08f37af01790b45b6190b16e February 8, 2015 @ 14:45
Yandex 30773 bytes b212742b08f37af01790b45b6190b16e June 20, 2013 @ 11:59

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 30971 bytes d3195b0fde819c9cff5a0dca3018c57d < /*
< Copyright (c) 2004-2010, 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 30915 bytes d3e7e526e89b2deebf19fc8f362385a0 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:

1.12.2, 1.12.1,
1.11.4, 1.11.3, 1.11.2, 1.11.1, 1.11.0,
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
29265 bytes -2 bytes zopfli --i100000 --mls8 --bsr22 --lazy --ohh December 2, 2015 @ 08:57
29267 bytes -6 bytes zopfli --i10000 --mls8 --bsr22 --lazy --ohh November 22, 2015 @ 22:14
29273 bytes -4 bytes zopfli --i1000 --mls8 --bsr22 --lazy --ohh September 22, 2015 @ 03:19
29277 bytes zopfli --i100 --mls8 --bsr22 --lazy --ohh September 21, 2015 @ 11:16

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
29301 29305 29309 29311 29329 29342 29340 29339 29343 29348 29349 29357 29341 29348 29338
29321 29328 29318 29286 29315 29318 29338 29336 29321 29334 29331 29331 29331 29344 29339
29301 29302 29305 29317 29302 29314 29331 29338 29315 29346 29338 29335 29340 29335 29336
29328 29318 29309 29313 29299 29283 29336 29305 29327 29345 29339 29331 29327 29338 29339
29316 29291 29311 29312 29310 29315 29308 29338 29308 29313 29309 29332 29340 29339 29335
29324 29316 29316 29324 29310 29285 29316 29322 29307 29346 29339 29331 29334 29338 29338
29299 29294 29316 29304 29308 29322 29316 29329 29291 29342 29282 29337 29332 29332 29332
29316 29308 29317 29307 29318 29315 29316 29336 29331 29330 29330 29330 29293 29333 29331
29322 29283 29323 29301 29311 29308 29339 29323 29323 29330 29332 29331 29301 29330 29330
29308 29309 29317 29294 29305 29289 29324 29320 29305 29330 29328 29332 29293 29337 29338
29308 29307 29330 29316 29306 29315 29335 29335 29330 29333 29330 29328 29333 29340 29339
29305 29310 29323 29306 29306 29309 29305 29310 29330 29330 29331 29329 29330 29340 29339
29292 29307 29315 29298 29314 29306 29310 29337 29292 29331 29336 29332 29333 29339 29337
29301 29316 29326 29306 29307 29310 29310 29315 29311 29334 29335 29331 29304 29338 29334
29301 29307 29309 29294 29305 29301 29336 29337 29307 29331 29338 29331 29333 29340 29339
29307 29315 29305 29308 29301 29286 29334 29310 29309 29345 29337 29330 29304 29340 29335
29308 29317 29289 29279 29291 29320 29301 29319 29330 29343 29300 29330 29309 29338 29339
29318 29316 29312 29311 29309 29315 29308 29338 29310 29342 29329 29331 29334 29334 29335
29295 29315 29265 29279 29286 29314 29334 29338 29327 29330 29337 29328 29333 29336 29334
29317 29309 29326 29302 29304 29316 29308 29338 29310 29332 29335 29330 29331 29330 29330
29316 29315 29319 29285 29304 29314 29335 29336 29319 29327 29305 29329 29294 29337 29334
29303 29308 29320 29320 29300 29312 29331 29338 29302 29331 29330 29331 29333 29336 29334
29308 29309 29319 29308 29310 29310 29335 29336 29306 29335 29285 29331 29337 29340 29339

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 29277 bytes 100%
1,000 29273 bytes -4 bytes 100%
10,000 29267 bytes -6 bytes 100%
100,000 29265 bytes -2 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
29391 bytes +126 bytes (+0.43%) +5 bytes
29386 bytes +121 bytes (+0.41%)
29426 bytes +161 bytes (+0.55%) +40 bytes
29389 bytes +124 bytes (+0.42%) +3 bytes
29428 bytes +163 bytes (+0.56%) +42 bytes
29418 bytes +153 bytes (+0.52%) +32 bytes
29429 bytes +164 bytes (+0.56%) +43 bytes
29400 bytes +135 bytes (+0.46%) +14 bytes
29438 bytes +173 bytes (+0.59%) +52 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 23188 bytes -6077 bytes (-20.77%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 26124 bytes -3141 bytes (-10.73%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 26998 bytes -2267 bytes (-7.75%)
Brotli (Wikipedia) brotli brotli -q 11 27146 bytes -2119 bytes (-7.24%)
LZMA2 (Wikipedia) xz xz -9 28064 bytes -1201 bytes (-4.10%)
ZSTD (Wikipedia) zstd zstd -19 28851 bytes -414 bytes (-1.41%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 28932 bytes -333 bytes (-1.14%)

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