Choose a version:
26% The original file has 639282 bytes (624.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 167922 bytes (164.0k, 26%).

After GZIP compression these minified files vary in size:
gzip -6 (default)
  56425 bytes (55.1k)
local copy
gzip -9
  56356 bytes (55.0k)
local copy
libdeflate -12
  53660 bytes (52.4k)
local copy
7zip -mx=9 -tgzip
  53648 bytes (52.4k)
local copy
kzip -s0 -rn -b1
  53573 bytes (52.3k)
local copy
zultra
  53573 bytes (52.3k)
local copy
pigz -11 -n
  53562 bytes (52.3k)
local copy
Zopfli
  53481 bytes (52.2k)
local copy
Zopfli (defluff)
  53479 bytes (52.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.15.5.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.15.5 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 --bsr13 --lazy --ohh

(found March 23, 2021)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 128  --mls128
block splitting recursion 13  --bsr13
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 2 more bytes (53479 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.5/dojo.js --location | md5sum
50a3f1dc1234020b6a13f24d356cacac  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.5.min.zopfli.js.gz | md5sum
50a3f1dc1234020b6a13f24d356cacac  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.5/dojo.js --location | sha1sum
a75730cb52da7ef723b04f21f4be8f51411cd733  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.5.min.zopfli.js.gz | sha1sum
a75730cb52da7ef723b04f21f4be8f51411cd733  -

Other Versions

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

1.16.4, 1.16.3, 1.16.2, 1.16.1, 1.16.0,
1.15.5, 1.15.4, 1.15.3, 1.15.2, 1.15.1, 1.15.0,
1.14.8, 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
53481 bytes -3 bytes zopfli --i1000000 --mls128 --bsr13 --lazy --ohh March 23, 2021 @ 21:09
53484 bytes -2 bytes zopfli --i100000 --mls128 --bsr13 --lazy --ohh March 23, 2021 @ 13:20
53486 bytes -1 byte zopfli --i100000 --mls256 --bsr2 --lazy --ohh March 23, 2021 @ 12:47
53487 bytes -1 byte zopfli --i10000 --mls256 --bsr2 --lazy --ohh March 23, 2021 @ 04:55
53488 bytes -7 bytes zopfli --i10000 --mls64 --bsr11 --lazy --ohh March 22, 2021 @ 17:15
53495 bytes -1 byte zopfli --i1000 --mls32 --bsr10 --lazy --ohh March 22, 2021 @ 16:50
53496 bytes -2 bytes zopfli --i1000 --mls32 --bsr14 --lazy --ohh March 22, 2021 @ 15:45
53498 bytes -1 byte zopfli --i1000 --mls128 --bsr18 --lazy --ohh March 22, 2021 @ 15:34
53499 bytes zopfli --i100 --mls32 --bsr14 --lazy --ohh March 22, 2021 @ 15:27

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

Most recent activity on March 24, 2021 @ 16:46.

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
53529 53495 53492 53492 53494 53496 53488 53486 53503 53507 53506 53495 53494 53522 53509
53527 53521 53496 53499 53499 53501 53489 53490 53499 53492 53493 53500 53495 53508 53495
53519 53521 53496 53492 53497 53497 53489 53499 53498 53502 53505 53494 53502 53505 53501
53501 53530 53492 53520 53495 53504 53502 53491 53498 53492 53506 53494 53504 53494 53504
53524 53517 53494 53529 53493 53498 53487 53492 53504 53504 53508 53493 53495 53505 53503
53519 53517 53498 53492 53499 53493 53489 53491 53498 53498 53507 53494 53490 53508 53513
53491 53492 53525 53526 53489 53491 53502 53490 53498 53499 53500 53496 53490 53508 53509
53507 53508 53496 53522 53490 53481 53491 53496 53498 53497 53506 53494 53503 53500 53501
53524 53521 53495 53531 53489 53490 53491 53492 53498 53498 53503 53496 53501 53499 53503
53519 53520 53493 53492 53493 53496 53481 53491 53499 53497 53503 53498 53491 53502 53498
53508 53517 53537 53525 53491 53494 53497 53492 53499 53503 53501 53497 53501 53499 53506
53521 53505 53493 53492 53490 53504 53502 53491 53497 53501 53506 53494 53499 53505 53506
53517 53521 53518 53528 53490 53507 53489 53499 53498 53499 53500 53502 53504 53506 53506
53518 53517 53523 53532 53495 53499 53481 53490 53498 53499 53504 53492 53503 53500 53512
53504 53494 53489 53518 53493 53492 53487 53498 53498 53498 53507 53491 53499 53503 53510
53508 53492 53491 53491 53495 53507 53481 53490 53499 53498 53504 53493 53504 53502 53508
53510 53492 53493 53492 53493 53502 53481 53499 53501 53498 53506 53492 53492 53511 53501
53519 53523 53520 53525 53489 53492 53500 53492 53498 53498 53505 53491 53492 53505 53510
53508 53516 53519 53492 53494 53506 53481 53490 53498 53499 53501 53496 53492 53497 53506
53508 53520 53490 53523 53489 53507 53489 53499 53498 53501 53506 53492 53493 53499 53507
53518 53521 53521 53523 53491 53498 53481 53499 53499 53502 53501 53501 53492 53503 53500
53519 53521 53491 53492 53494 53501 53490 53498 53498 53497 53502 53492 53506 53515 53509
53517 53514 53516 53492 53491 53507 53488 53499 53499 53497 53500 53496 53501 53495 53510

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 53499 bytes 100%
1,000 53495 bytes -4 bytes 100%
10,000 53487 bytes -8 bytes 100%
100,000 53484 bytes -3 bytes 3.48%
1,000,000 53481 bytes -3 bytes 2.03%
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
53658 bytes +177 bytes (+0.33%) +85 bytes
53573 bytes +92 bytes (+0.17%)
53604 bytes +123 bytes (+0.23%) +31 bytes
53628 bytes +147 bytes (+0.27%) +55 bytes
53658 bytes +177 bytes (+0.33%) +85 bytes
53672 bytes +191 bytes (+0.36%) +99 bytes
53713 bytes +232 bytes (+0.43%) +140 bytes
53733 bytes +252 bytes (+0.47%) +160 bytes
53717 bytes +236 bytes (+0.44%) +144 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 39319 bytes -14162 bytes (-26.48%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 46928 bytes -6553 bytes (-12.25%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 47846 bytes -5635 bytes (-10.54%)
Brotli (Wikipedia) brotli brotli -q 11 49436 bytes -4045 bytes (-7.56%)
LZMA2 (Wikipedia) xz xz -9 50440 bytes -3041 bytes (-5.69%)
Zstandard (Wikipedia) zstd zstd -19 51805 bytes -1676 bytes (-3.13%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 52106 bytes -1375 bytes (-2.57%)

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 2021.
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.