Choose a version:
24% The original file has 377546 bytes (368.7k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 90538 bytes (88.4k, 24%).

After GZIP compression these minified files vary in size:
Boot
  35481 bytes (34.6k)
CDN, direct link
cdnhttps
  31019 bytes (30.3k)
CDN, direct link
cdnjs
  30971 bytes (30.2k)
CDN, direct link
gzip -6 (default)
  30873 bytes (30.1k)
local copy
gzip -9
  30833 bytes (30.1k)
local copy
libdeflate -12
  29474 bytes (28.8k)
local copy
7zip -mx=9 -tgzip
  29460 bytes (28.8k)
local copy
kzip -s0 -rn -b4
  29427 bytes (28.7k)
local copy
pigz -11 -n
  29407 bytes (28.7k)
local copy
Zopfli
  29308 bytes (28.6k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.5.3.min.js

You will automatically get the smallest Dojo 1.5.3 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 1663 bytes by using my Dojo 1.5.3 Zopfli version instead of the best available CDN (5.67% smaller than cdnjs, 29308 vs. 30971 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 --bsr22 --lazy --ohh

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

Verify file integrity

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

MD5:
curl --silent --compressed http://download.dojotoolkit.org/release-1.5.3/dojo.js --location | md5sum
1ab41d7c357e3148b00b5ebf19798a15  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.5.3.min.zopfli.js.gz | md5sum
1ab41d7c357e3148b00b5ebf19798a15  -

SHA1:
curl --silent --compressed http://download.dojotoolkit.org/release-1.5.3/dojo.js --location | sha1sum
091a184b4af4729d6ea7818ad18c54856d9b26bb  -
curl --silent --compressed http://minime.stephan-brumme.com/files/dojo/dojo-1.5.3.min.zopfli.js.gz | sha1sum
091a184b4af4729d6ea7818ad18c54856d9b26bb  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 35481 bytes 1ab41d7c357e3148b00b5ebf19798a15 March 19, 2015 @ 15:32
cdnjs 30971 bytes 1ab41d7c357e3148b00b5ebf19798a15 February 8, 2015 @ 14:45

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
cdnhttps 31019 bytes 6c9acd157774b3d0fad35fece46e5cb3 < /*
< 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:

1.12.2, 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
29308 bytes -3 bytes zopfli --i100000 --mls2 --bsr22 --lazy --ohh December 2, 2015 @ 09:06
29311 bytes -5 bytes zopfli --i10000 --mls2 --bsr22 --lazy --ohh October 21, 2015 @ 13:35
29316 bytes -6 bytes zopfli --i1000 --mls2 --bsr22 --lazy --ohh September 23, 2015 @ 16:32
29322 bytes zopfli --i100 --mls2 --bsr22 --lazy --ohh September 22, 2015 @ 10:43

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 @ 14:37.

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
29358 29363 29363 29372 29387 29384 29388 29378 29394 29404 29396 29408 29391 29398 29389
29377 29381 29371 29358 29365 29380 29351 29387 29350 29388 29383 29389 29392 29397 29389
29372 29381 29348 29371 29360 29361 29343 29386 29364 29393 29392 29380 29394 29398 29387
29351 29375 29364 29357 29379 29362 29359 29389 29358 29392 29383 29392 29395 29389 29393
29367 29354 29361 29365 29365 29372 29364 29346 29347 29362 29386 29381 29381 29385 29385
29372 29350 29366 29377 29340 29359 29370 29342 29383 29380 29390 29382 29343 29385 29385
29372 29351 29347 29363 29358 29363 29367 29388 29344 29380 29379 29392 29362 29395 29386
29373 29342 29331 29336 29343 29358 29370 29343 29367 29383 29382 29382 29335 29384 29384
29355 29353 29362 29366 29360 29358 29360 29368 29359 29379 29382 29392 29348 29396 29383
29360 29361 29349 29356 29347 29361 29373 29373 29345 29381 29381 29382 29358 29393 29394
29362 29366 29367 29356 29357 29368 29345 29360 29382 29383 29385 29382 29382 29394 29393
29361 29362 29365 29366 29367 29356 29361 29341 29369 29385 29381 29382 29349 29387 29393
29359 29363 29366 29357 29355 29341 29346 29388 29363 29382 29382 29391 29383 29392 29393
29360 29361 29370 29359 29354 29342 29366 29367 29358 29382 29382 29382 29380 29386 29392
29373 29372 29367 29357 29365 29355 29350 29367 29331 29394 29382 29386 29377 29392 29392
29372 29374 29371 29351 29348 29373 29347 29345 29358 29380 29388 29392 29383 29387 29388
29373 29371 29367 29360 29334 29368 29365 29366 29352 29383 29380 29382 29381 29392 29386
29372 29371 29371 29339 29371 29363 29360 29366 29382 29384 29382 29380 29377 29391 29393
29308 29372 29364 29344 29344 29367 29349 29388 29336 29379 29385 29382 29378 29389 29387
29369 29364 29371 29366 29361 29364 29356 29367 29360 29381 29382 29391 29337 29387 29393
29368 29364 29366 29355 29363 29356 29346 29366 29343 29379 29335 29390 29383 29391 29383
29361 29356 29364 29364 29369 29359 29352 29348 29359 29380 29383 29382 29377 29393 29383
29361 29362 29366 29369 29344 29364 29345 29365 29388 29380 29383 29394 29378 29393 29393

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 29322 bytes 100%
1,000 29316 bytes -6 bytes 100%
10,000 29311 bytes -5 bytes 100%
100,000 29308 bytes -3 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
29442 bytes +134 bytes (+0.46%) +15 bytes
29454 bytes +146 bytes (+0.50%) +27 bytes
29480 bytes +172 bytes (+0.59%) +53 bytes
29461 bytes +153 bytes (+0.52%) +34 bytes
29427 bytes +119 bytes (+0.41%)
29471 bytes +163 bytes (+0.56%) +44 bytes
29456 bytes +148 bytes (+0.50%) +29 bytes
29476 bytes +168 bytes (+0.57%) +49 bytes
29517 bytes +209 bytes (+0.71%) +90 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 23255 bytes -6053 bytes (-20.65%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 26170 bytes -3138 bytes (-10.71%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 27081 bytes -2227 bytes (-7.60%)
Brotli (Wikipedia) brotli brotli -q 11 27198 bytes -2110 bytes (-7.20%)
LZMA2 (Wikipedia) xz xz -9 28112 bytes -1196 bytes (-4.08%)
ZSTD (Wikipedia) zstd zstd -19 28901 bytes -407 bytes (-1.39%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 28969 bytes -339 bytes (-1.16%)

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