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
  53649 bytes (52.4k)
local copy
kzip -s0 -rn -b1
  53575 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-1.15.4.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.15.4 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 --bsr18 --lazy --ohh

(found June 18, 2020)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 128  --mls128
block splitting recursion 18  --bsr18
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-1.15.4/dojo.js --location | md5sum
72133feb44e10fd2764d2b8d7cd5f92e  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.4.min.zopfli.js.gz | md5sum
72133feb44e10fd2764d2b8d7cd5f92e  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.4/dojo.js --location | sha1sum
9ec0f1e859550f8c356cb202cad1b0bac4bdc961  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.4.min.zopfli.js.gz | sha1sum
9ec0f1e859550f8c356cb202cad1b0bac4bdc961  -

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
53481 bytes -3 bytes zopfli --i1000000 --mls128 --bsr18 --lazy --ohh June 18, 2020 @ 21:54
53484 bytes -3 bytes zopfli --i100000 --mls128 --bsr40 --lazy --ohh June 17, 2020 @ 10:44
53487 bytes -1 byte zopfli --i10000 --mls256 --bsr2 --lazy --ohh June 16, 2020 @ 01:53
53488 bytes -2 bytes zopfli --i10000 --mls128 --bsr18 --lazy --ohh June 15, 2020 @ 15:48
53490 bytes -4 bytes zopfli --i10000 --mls256 --bsr17 --lazy --ohh June 15, 2020 @ 15:02
53494 bytes -1 byte zopfli --i10000 --mls32 --bsr2 --lazy --ohh June 15, 2020 @ 14:54
53495 bytes -1 byte zopfli --i1000 --mls32 --bsr12 --lazy --ohh June 15, 2020 @ 12:30
53496 bytes -1 byte zopfli --i1000 --mls8 --bsr23 --lazy --ohh June 15, 2020 @ 12:07
53497 bytes -1 byte zopfli --i1000 --mls8192 --bsr9 --lazy --ohh June 15, 2020 @ 12:04
53498 bytes -1 byte zopfli --i1000 --mls32 --bsr23 --lazy --ohh June 15, 2020 @ 12:00
53499 bytes zopfli --i100 --mls32 --bsr14 --lazy --ohh June 15, 2020 @ 11:38

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
53529 53491 53492 53492 53494 53495 53487 53486 53503 53506 53506 53495 53494 53522 53509
53527 53521 53496 53494 53499 53503 53489 53490 53498 53492 53493 53498 53495 53509 53495
53519 53521 53496 53492 53501 53497 53489 53499 53499 53507 53505 53495 53502 53506 53501
53501 53531 53492 53491 53495 53501 53502 53492 53498 53492 53506 53494 53501 53493 53504
53524 53519 53495 53530 53494 53498 53481 53493 53504 53503 53509 53493 53494 53505 53503
53520 53517 53498 53492 53499 53494 53490 53491 53498 53497 53507 53497 53491 53507 53509
53492 53492 53525 53526 53489 53491 53502 53490 53497 53499 53500 53496 53491 53508 53509
53507 53506 53496 53523 53490 53489 53491 53489 53498 53498 53506 53494 53505 53500 53497
53524 53521 53496 53531 53489 53490 53492 53493 53499 53499 53503 53495 53503 53499 53503
53519 53521 53493 53492 53493 53497 53486 53491 53499 53498 53503 53498 53491 53504 53498
53508 53522 53532 53526 53492 53494 53497 53492 53499 53503 53501 53495 53500 53501 53506
53520 53505 53493 53492 53490 53504 53502 53491 53496 53506 53506 53494 53499 53499 53506
53518 53521 53517 53529 53490 53507 53489 53498 53498 53499 53500 53503 53504 53500 53505
53518 53517 53523 53533 53495 53500 53486 53490 53497 53498 53504 53492 53503 53500 53508
53505 53495 53489 53518 53492 53493 53481 53498 53497 53497 53507 53492 53499 53503 53510
53508 53492 53491 53492 53495 53499 53486 53490 53498 53499 53504 53493 53504 53500 53507
53510 53492 53493 53493 53493 53502 53486 53499 53501 53499 53506 53492 53493 53511 53493
53515 53523 53520 53525 53489 53493 53501 53492 53499 53499 53505 53492 53491 53505 53510
53508 53525 53520 53492 53494 53506 53486 53490 53499 53500 53501 53495 53492 53495 53506
53509 53520 53490 53490 53493 53506 53486 53498 53497 53506 53506 53492 53493 53503 53507
53519 53522 53521 53523 53492 53498 53486 53497 53500 53502 53501 53502 53492 53500 53507
53519 53521 53492 53493 53495 53500 53490 53498 53498 53498 53502 53492 53506 53510 53509
53517 53514 53516 53492 53492 53507 53481 53499 53499 53498 53500 53496 53506 53495 53511

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 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
53642 bytes +161 bytes (+0.30%) +67 bytes
53575 bytes +94 bytes (+0.18%)
53605 bytes +124 bytes (+0.23%) +30 bytes
53630 bytes +149 bytes (+0.28%) +55 bytes
53642 bytes +161 bytes (+0.30%) +67 bytes
53682 bytes +201 bytes (+0.38%) +107 bytes
53711 bytes +230 bytes (+0.43%) +136 bytes
53732 bytes +251 bytes (+0.47%) +157 bytes
53724 bytes +243 bytes (+0.45%) +149 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 39318 bytes -14163 bytes (-26.48%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 46927 bytes -6554 bytes (-12.25%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 47846 bytes -5635 bytes (-10.54%)
Brotli (Wikipedia) brotli brotli -q 11 49371 bytes -4110 bytes (-7.68%)
LZMA2 (Wikipedia) xz xz -9 50448 bytes -3033 bytes (-5.67%)
Zstandard (Wikipedia) zstd zstd -19 51805 bytes -1676 bytes (-3.13%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 52109 bytes -1372 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 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.