Choose a version:
26% The original file has 639090 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 167783 bytes (163.9k, 26%).

After GZIP compression these minified files vary in size:
gzip -6 (default)
  56370 bytes (55.0k)
local copy
gzip -9
  56301 bytes (55.0k)
local copy
libdeflate -12
  53627 bytes (52.4k)
local copy
7zip -mx=9 -tgzip
  53603 bytes (52.3k)
local copy
pigz -11 -n
  53533 bytes (52.3k)
local copy
kzip -s0 -rn -b1
  53526 bytes (52.3k)
local copy
Zopfli
  53439 bytes (52.2k)
local copy
Zopfli (defluff)
  53436 bytes (52.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.15.0.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.15.0 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

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 --mls256 --bsr19 --lazy --ohh

(found February 22, 2019)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 256  --mls256
block splitting recursion 19  --bsr19
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 3 more bytes (53436 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.0/dojo.js --location | md5sum
557e7937385d2c12babfb6cf9c5f92cd  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.0.min.zopfli.js.gz | md5sum
557e7937385d2c12babfb6cf9c5f92cd  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.0/dojo.js --location | sha1sum
9f41a44b4d4a0d8637b37954a82c164dbc7cf28c  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.0.min.zopfli.js.gz | sha1sum
9f41a44b4d4a0d8637b37954a82c164dbc7cf28c  -

Other Versions

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

1.15.0,
1.14.3, 1.14.2, 1.14.1, 1.14.0,
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,
1.11.7, 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,
1.6.3, 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
53439 bytes -2 bytes zopfli --i1000000 --mls256 --bsr19 --lazy --ohh February 22, 2019 @ 20:01
53441 bytes -1 byte zopfli --i100000 --mls256 --bsr19 --lazy --ohh February 21, 2019 @ 17:08
53442 bytes -1 byte zopfli --i100000 --mls256 --bsr2 --lazy --ohh February 20, 2019 @ 10:34
53443 bytes -3 bytes zopfli --i10000 --mls256 --bsr2 --lazy --ohh February 19, 2019 @ 19:56
53446 bytes -3 bytes zopfli --i10000 --mls8192 --bsr9 --lazy --ohh February 19, 2019 @ 16:06
53449 bytes -2 bytes zopfli --i10000 --mls128 --bsr9 --lazy --ohh February 19, 2019 @ 14:32
53451 bytes -1 byte zopfli --i10000 --mls64 --bsr9 --lazy --ohh February 19, 2019 @ 13:25
53452 bytes -2 bytes zopfli --i10000 --mls4096 --bsr9 --lazy --ohh February 19, 2019 @ 13:01
53454 bytes -1 byte zopfli --i1000 --mls8192 --bsr9 --lazy --ohh February 19, 2019 @ 10:43
53455 bytes -2 bytes zopfli --i1000 --mls128 --bsr20 --lazy --ohh February 19, 2019 @ 07:40
53457 bytes -1 byte zopfli --i1000 --mls32 --bsr2 --lazy --ohh February 19, 2019 @ 07:34
53458 bytes zopfli --i100 --mls8192 --bsr40 --lazy --ohh February 18, 2019 @ 20:24

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

Most recent activity on February 25, 2019 @ 07:32.

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
53480 53448 53449 53449 53449 53450 53449 53442 53470 53469 53467 53453 53453 53485 53462
53498 53483 53453 53449 53452 53457 53449 53448 53458 53451 53467 53454 53452 53468 53454
53480 53494 53447 53447 53453 53462 53446 53459 53457 53457 53464 53469 53454 53466 53466
53474 53448 53487 53449 53451 53455 53448 53448 53457 53454 53456 53454 53455 53467 53456
53481 53478 53484 53487 53447 53456 53447 53447 53467 53457 53471 53448 53449 53466 53463
53455 53474 53447 53448 53447 53451 53449 53439 53457 53457 53474 53452 53446 53471 53457
53493 53447 53450 53489 53449 53447 53458 53447 53458 53459 53461 53454 53448 53465 53465
53491 53446 53450 53447 53450 53446 53448 53447 53457 53457 53460 53450 53455 53468 53459
53480 53483 53478 53454 53448 53447 53447 53448 53457 53457 53464 53455 53455 53457 53456
53476 53478 53450 53449 53449 53455 53446 53447 53457 53457 53460 53449 53448 53466 53463
53484 53489 53490 53483 53451 53450 53453 53448 53458 53459 53460 53453 53454 53465 53454
53475 53483 53446 53449 53447 53461 53442 53447 53458 53457 53464 53455 53449 53466 53460
53478 53482 53479 53488 53448 53462 53446 53459 53455 53459 53460 53462 53456 53467 53460
53475 53487 53490 53495 53447 53458 53446 53458 53458 53457 53459 53448 53455 53457 53457
53475 53447 53450 53486 53448 53447 53446 53458 53457 53457 53463 53451 53456 53462 53462
53475 53448 53450 53451 53455 53456 53446 53439 53457 53458 53463 53452 53451 53470 53458
53481 53484 53450 53449 53452 53462 53446 53457 53457 53457 53473 53454 53447 53466 53458
53481 53486 53450 53448 53452 53450 53458 53448 53457 53457 53464 53461 53447 53466 53455
53471 53487 53450 53486 53447 53468 53446 53447 53457 53456 53460 53450 53448 53454 53457
53448 53453 53447 53448 53448 53455 53446 53458 53457 53457 53466 53452 53450 53464 53461
53477 53480 53450 53447 53451 53462 53446 53458 53463 53460 53460 53449 53446 53468 53462
53481 53482 53447 53448 53451 53461 53448 53458 53457 53457 53463 53450 53454 53466 53455
53479 53483 53455 53449 53452 53458 53440 53458 53457 53457 53459 53470 53450 53467 53458

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 53458 bytes 100%
1,000 53454 bytes -4 bytes 100%
10,000 53443 bytes -11 bytes 100%
100,000 53441 bytes -2 bytes 1.45%
1,000,000 53439 bytes -2 bytes 0.87%
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
53607 bytes +168 bytes (+0.31%) +81 bytes
53526 bytes +87 bytes (+0.16%)
53560 bytes +121 bytes (+0.23%) +34 bytes
53591 bytes +152 bytes (+0.28%) +65 bytes
53607 bytes +168 bytes (+0.31%) +81 bytes
53606 bytes +167 bytes (+0.31%) +80 bytes
53606 bytes +167 bytes (+0.31%) +80 bytes
53656 bytes +217 bytes (+0.41%) +130 bytes
53680 bytes +241 bytes (+0.45%) +154 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 39285 bytes -14154 bytes (-26.49%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 46911 bytes -6528 bytes (-12.22%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 47837 bytes -5602 bytes (-10.48%)
Brotli (Wikipedia) brotli brotli -q 11 49360 bytes -4079 bytes (-7.63%)
LZMA2 (Wikipedia) xz xz -9 50436 bytes -3003 bytes (-5.62%)
Zstandard (Wikipedia) zstd zstd -19 51764 bytes -1675 bytes (-3.13%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 52089 bytes -1350 bytes (-2.53%)

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 2019.
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