Choose a version:
26% The original file has 639407 bytes (624.4k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 167969 bytes (164.0k, 26%).

After GZIP compression these minified files vary in size:
gzip -6 (default)
  56446 bytes (55.1k)
local copy
gzip -9
  56377 bytes (55.1k)
local copy
libdeflate -12
  53683 bytes (52.4k)
local copy
7zip -mx=9 -tgzip
  53672 bytes (52.4k)
local copy
kzip -s0 -rn -b1
  53603 bytes (52.3k)
local copy
zultra
  53594 bytes (52.3k)
local copy
pigz -11 -n
  53580 bytes (52.3k)
local copy
Zopfli
  53507 bytes (52.3k)
local copy
Zopfli (defluff)
  53504 bytes (52.3k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/dojo/dojo-1.15.6.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.15.6 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 --i100000 --mb8 --mls256 --bsr2 --lazy --ohh

(found March 3, 2022)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 256  --mls256
block splitting recursion 2  --bsr2
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 (53504 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.6/dojo.js --location | md5sum
b0b73b07ba7eb2d823fd6d2ad23231b5  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.6.min.zopfli.js.gz | md5sum
b0b73b07ba7eb2d823fd6d2ad23231b5  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.6/dojo.js --location | sha1sum
1b5f6bd5439e0ab40e8f7e962c30bb029426bacc  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.6.min.zopfli.js.gz | sha1sum
1b5f6bd5439e0ab40e8f7e962c30bb029426bacc  -

Other Versions

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

1.17.2, 1.17.1, 1.17.0,
1.16.5, 1.16.4, 1.16.3, 1.16.2, 1.16.1, 1.16.0,
1.15.6, 1.15.5, 1.15.4, 1.15.3, 1.15.2, 1.15.1, 1.15.0,
1.14.9, 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,
1.13.10, 1.13.9, 1.13.8, 1.13.7, 1.13.6, 1.13.5, 1.13.4, 1.13.3, 1.13.2, 1.13.1, 1.13.0,
1.12.11, 1.12.10, 1.12.9, 1.12.8, 1.12.7, 1.12.6, 1.12.5, 1.12.4, 1.12.3, 1.12.2, 1.12.1,
1.11.13, 1.11.12, 1.11.11, 1.11.10, 1.11.9, 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
53507 bytes -1 byte zopfli --i100000 --mls256 --bsr2 --lazy --ohh March 3, 2022 @ 10:47
53508 bytes -1 byte zopfli --i10000 --mls256 --bsr2 --lazy --ohh February 25, 2022 @ 16:47
53509 bytes -1 byte zopfli --i10000 --mls128 --bsr4 --lazy --ohh February 25, 2022 @ 11:18
53510 bytes -8 bytes zopfli --i10000 --mls32 --bsr12 --lazy --ohh February 25, 2022 @ 10:00
53518 bytes -1 byte zopfli --i1000 --mls32 --bsr15 --lazy --ohh February 24, 2022 @ 19:57
53519 bytes -1 byte zopfli --i1000 --mls32 --bsr40 --lazy --ohh February 24, 2022 @ 18:41
53520 bytes -1 byte zopfli --i1000 --mls128 --bsr16 --lazy --ohh February 24, 2022 @ 17:46
53521 bytes -1 byte zopfli --i1000 --mls256 --bsr21 --lazy --ohh February 24, 2022 @ 17:40
53522 bytes zopfli --i100 --mls32 --bsr40 --lazy --ohh February 24, 2022 @ 15:16

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

Most recent activity on March 3, 2022 @ 21:35.

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
53546 53513 53513 53514 53517 53512 53509 53507 53528 53528 53528 53516 53517 53544 53532
53542 53543 53517 53517 53520 53525 53509 53513 53520 53516 53515 53523 53516 53534 53518
53544 53543 53517 53515 53519 53523 53511 53521 53519 53520 53525 53514 53523 53512 53532
53529 53552 53514 53554 53517 53524 53521 53519 53519 53519 53518 53515 53519 53510 53523
53542 53542 53516 53558 53515 53527 53510 53513 53527 53527 53525 53514 53514 53527 53524
53543 53550 53519 53517 53524 53514 53511 53520 53522 53519 53529 53515 53511 53528 53527
53513 53514 53543 53555 53511 53514 53524 53512 53525 53520 53519 53518 53511 53528 53530
53529 53529 53518 53515 53511 53508 53513 53511 53522 53518 53527 53518 53525 53521 53518
53542 53543 53516 53557 53510 53510 53513 53513 53522 53519 53525 53513 53511 53520 53527
53541 53539 53514 53515 53514 53521 53511 53514 53522 53518 53524 53524 53514 53522 53528
53530 53529 53543 53554 53513 53515 53519 53513 53518 53523 53523 53519 53524 53521 53529
53530 53513 53514 53541 53511 53528 53520 53512 53519 53519 53528 53516 53513 53532 53529
53541 53541 53538 53549 53511 53528 53511 53520 53522 53513 53522 53525 53524 53524 53532
53545 53540 53541 53555 53517 53524 53511 53521 53523 53519 53522 53514 53523 53521 53530
53513 53516 53517 53545 53514 53514 53511 53520 53519 53521 53527 53516 53512 53520 53535
53530 53513 53513 53513 53517 53528 53511 53511 53521 53519 53525 53515 53512 53525 53522
53531 53513 53516 53515 53514 53525 53511 53521 53522 53519 53528 53519 53524 53532 53515
53537 53543 53542 53546 53510 53513 53512 53515 53522 53519 53525 53525 53512 53525 53530
53526 53546 53515 53542 53515 53527 53511 53513 53519 53520 53522 53524 53513 53518 53529
53529 53538 53511 53539 53512 53529 53510 53520 53519 53519 53523 53513 53515 53524 53526
53543 53543 53544 53546 53513 53519 53511 53519 53520 53523 53522 53519 53513 53526 53528
53540 53542 53513 53514 53511 53526 53511 53519 53522 53518 53523 53517 53537 53531 53530
53540 53538 53513 53540 53513 53526 53510 53520 53522 53518 53523 53517 53521 53516 53531

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 53522 bytes 100%
1,000 53518 bytes -4 bytes 100%
10,000 53508 bytes -10 bytes 100%
100,000 53507 bytes -1 byte 1.16%
1,000,000 53507 bytes 0.29%
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
53671 bytes +164 bytes (+0.31%) +68 bytes
53603 bytes +96 bytes (+0.18%)
53629 bytes +122 bytes (+0.23%) +26 bytes
53653 bytes +146 bytes (+0.27%) +50 bytes
53678 bytes +171 bytes (+0.32%) +75 bytes
53716 bytes +209 bytes (+0.39%) +113 bytes
53742 bytes +235 bytes (+0.44%) +139 bytes
53760 bytes +253 bytes (+0.47%) +157 bytes
53741 bytes +234 bytes (+0.44%) +138 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 39330 bytes -14177 bytes (-26.50%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 46940 bytes -6567 bytes (-12.27%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 47853 bytes -5654 bytes (-10.57%)
Brotli (Wikipedia) brotli brotli -q 11 49377 bytes -4130 bytes (-7.72%)
LZMA2 (Wikipedia) xz xz -9 50460 bytes -3047 bytes (-5.69%)
Zstandard (Wikipedia) zstd zstd -19 51821 bytes -1686 bytes (-3.15%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 52134 bytes -1373 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 2022.
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.