Choose a version:
26% The original file has 639053 bytes (624.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 167756 bytes (163.8k, 26%).

After GZIP compression these minified files vary in size:
gzip -6 (default)
  56357 bytes (55.0k)
local copy
gzip -9
  56287 bytes (55.0k)
local copy
libdeflate -12
  53616 bytes (52.4k)
local copy
7zip -mx=9 -tgzip
  53590 bytes (52.3k)
local copy
zultra
  53523 bytes (52.3k)
local copy
kzip -s0 -rn -b1
  53519 bytes (52.3k)
local copy
pigz -11 -n
  53519 bytes (52.3k)
local copy
Zopfli
  53425 bytes (52.2k)
local copy
Zopfli (defluff)
  53424 bytes (52.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.15.2.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.15.2 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

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 --i1000000 --mb8 --mls128 --bsr16 --lazy --ohh

(found February 24, 2020)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 128  --mls128
block splitting recursion 16  --bsr16
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 (53424 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.2/dojo.js --location | md5sum
a1429839cfb5699eaf4ab68b1508d064  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.2.min.zopfli.js.gz | md5sum
a1429839cfb5699eaf4ab68b1508d064  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.2/dojo.js --location | sha1sum
208161ec06d2a587818cca66f4e3b78b28f18184  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.2.min.zopfli.js.gz | sha1sum
208161ec06d2a587818cca66f4e3b78b28f18184  -

Other Versions

Available Dojo versions at minime.stephan-brumme.com:

1.16.3, 1.16.2, 1.16.1, 1.16.0,
1.15.4, 1.15.3, 1.15.2, 1.15.1, 1.15.0,
1.14.7, 1.14.6, 1.14.5, 1.14.4, 1.14.3, 1.14.2, 1.14.1, 1.14.0,
1.13.5, 1.13.4, 1.13.3, 1.13.2, 1.13.1, 1.13.0,
1.12.5, 1.12.4, 1.12.3, 1.12.2, 1.12.1,
1.11.8, 1.11.7, 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,
1.6.5, 1.6.4, 1.6.3, 1.6.2, 1.6.1, 1.6.0,
1.5.6, 1.5.5, 1.5.4, 1.5.3, 1.5.2, 1.5.1, 1.5.0,
1.4.8, 1.4.7, 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, 1.2.2

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
53425 bytes -1 byte zopfli --i1000000 --mls128 --bsr16 --lazy --ohh February 24, 2020 @ 16:25
53426 bytes -2 bytes zopfli --i100000 --mls128 --bsr16 --lazy --ohh February 19, 2020 @ 20:09
53428 bytes -4 bytes zopfli --i100000 --mls256 --bsr8 --lazy --ohh February 19, 2020 @ 19:15
53432 bytes -1 byte zopfli --i10000 --mls128 --bsr16 --lazy --ohh February 19, 2020 @ 18:40
53433 bytes -7 bytes zopfli --i10000 --mls256 --bsr8 --lazy --ohh February 19, 2020 @ 18:22
53440 bytes -1 byte zopfli --i1000 --mls256 --bsr8 --lazy --ohh February 19, 2020 @ 16:14
53441 bytes -1 byte zopfli --i1000 --mls32 --bsr20 --lazy --ohh February 19, 2020 @ 15:02
53442 bytes -1 byte zopfli --i1000 --mls8192 --bsr20 --lazy --ohh February 19, 2020 @ 14:01
53443 bytes -1 byte zopfli --i1000 --mls256 --bsr22 --lazy --ohh February 19, 2020 @ 14:00
53444 bytes zopfli --i100 --mls8192 --bsr9 --lazy --ohh February 19, 2020 @ 13:53

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on July 20, 2020 @ 12:51.

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, 100,000 or 1,000,000.
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
53472 53433 53435 53434 53435 53435 53435 53432 53455 53447 53439 53437 53440 53472 53457
53465 53469 53439 53435 53438 53446 53435 53434 53443 53436 53456 53441 53439 53455 53439
53470 53481 53434 53439 53439 53448 53434 53443 53446 53443 53448 53457 53443 53452 53444
53465 53434 53438 53467 53433 53446 53441 53442 53443 53439 53450 53440 53449 53459 53440
53462 53468 53465 53467 53433 53443 53434 53428 53455 53444 53456 53435 53435 53451 53445
53447 53466 53433 53433 53433 53437 53435 53432 53443 53443 53456 53434 53434 53457 53443
53479 53434 53436 53470 53436 53434 53444 53433 53444 53444 53445 53441 53435 53451 53449
53432 53432 53436 53433 53435 53432 53434 53433 53443 53443 53444 53434 53453 53441 53444
53467 53470 53465 53440 53435 53433 53434 53432 53443 53444 53448 53441 53441 53448 53442
53467 53466 53433 53447 53444 53442 53432 53434 53444 53443 53444 53455 53439 53453 53448
53433 53476 53480 53470 53438 53437 53425 53436 53442 53446 53445 53440 53441 53451 53441
53465 53434 53426 53436 53447 53445 53425 53434 53443 53443 53449 53441 53435 53455 53446
53464 53468 53462 53475 53434 53449 53425 53444 53442 53444 53450 53449 53442 53453 53446
53470 53474 53476 53483 53433 53444 53432 53443 53444 53444 53444 53454 53453 53447 53442
53465 53433 53433 53468 53434 53433 53432 53442 53443 53444 53447 53439 53453 53447 53453
53467 53434 53433 53437 53438 53444 53432 53435 53442 53444 53448 53455 53434 53456 53442
53467 53471 53433 53435 53434 53448 53432 53442 53443 53444 53455 53439 53435 53453 53443
53468 53471 53433 53468 53439 53436 53432 53433 53443 53444 53447 53434 53457 53452 53442
53463 53474 53436 53434 53433 53455 53432 53434 53442 53442 53450 53434 53442 53449 53442
53433 53437 53460 53435 53435 53443 53432 53443 53444 53443 53451 53436 53439 53442 53450
53464 53464 53434 53433 53434 53435 53432 53443 53446 53445 53446 53446 53442 53452 53449
53464 53469 53433 53434 53438 53446 53432 53434 53443 53446 53447 53455 53440 53453 53441
53465 53469 53438 53435 53434 53444 53428 53427 53444 53443 53444 53456 53452 53453 53444

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 53444 bytes 100%
1,000 53440 bytes -4 bytes 100%
10,000 53431 bytes -9 bytes 100%
100,000 53426 bytes -5 bytes 2.03%
1,000,000 53425 bytes -1 byte 1.16%
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
53601 bytes +176 bytes (+0.33%) +82 bytes
53519 bytes +94 bytes (+0.18%)
53548 bytes +123 bytes (+0.23%) +29 bytes
53576 bytes +151 bytes (+0.28%) +57 bytes
53603 bytes +178 bytes (+0.33%) +84 bytes
53599 bytes +174 bytes (+0.33%) +80 bytes
53591 bytes +166 bytes (+0.31%) +72 bytes
53640 bytes +215 bytes (+0.40%) +121 bytes
53664 bytes +239 bytes (+0.45%) +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 - for example, your browser actually supports it !
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 39277 bytes -14148 bytes (-26.48%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 46900 bytes -6525 bytes (-12.21%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 47825 bytes -5600 bytes (-10.48%)
Brotli (Wikipedia) brotli brotli -q 11 49281 bytes -4144 bytes (-7.76%)
LZMA2 (Wikipedia) xz xz -9 50420 bytes -3005 bytes (-5.62%)
Zstandard (Wikipedia) zstd zstd -19 51751 bytes -1674 bytes (-3.13%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 52080 bytes -1345 bytes (-2.52%)

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 2020.
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

All trademarks are property of their respective owners. You know, the boring legal stuff.