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)
  56356 bytes (55.0k)
local copy
gzip -9
  56286 bytes (55.0k)
local copy
libdeflate -12
  53615 bytes (52.4k)
local copy
7zip -mx=9 -tgzip
  53589 bytes (52.3k)
local copy
kzip -s0 -rn -b1
  53518 bytes (52.3k)
local copy
pigz -11 -n
  53518 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-1.15.1.min.js (or via HTTPS)

You will automatically get the smallest Dojo 1.15.1 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 --mls128 --bsr14 --lazy --ohh

(found December 2, 2019)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 128  --mls128
block splitting recursion 14  --bsr14
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-1.15.1/dojo.js --location | md5sum
a792fbdae81376c56e81c02be6615f82  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.1.min.zopfli.js.gz | md5sum
a792fbdae81376c56e81c02be6615f82  -

SHA1:
curl --silent --compressed https://download.dojotoolkit.org/release-1.15.1/dojo.js --location | sha1sum
d9793c2d7f3b77a894107395e53942655062fc85  -
curl --silent --compressed https://minime.stephan-brumme.com/files/dojo/dojo-1.15.1.min.zopfli.js.gz | sha1sum
d9793c2d7f3b77a894107395e53942655062fc85  -

Other Versions

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

1.16.0,
1.15.1, 1.15.0,
1.14.4, 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
53425 bytes -1 byte zopfli --i100000 --mls128 --bsr14 --lazy --ohh December 2, 2019 @ 01:21
53426 bytes -4 bytes zopfli --i100000 --mls128 --bsr15 --lazy --ohh December 1, 2019 @ 23:45
53430 bytes -1 byte zopfli --i10000 --mls128 --bsr15 --lazy --ohh November 30, 2019 @ 03:27
53431 bytes -2 bytes zopfli --i10000 --mls128 --bsr13 --lazy --ohh November 30, 2019 @ 00:57
53433 bytes -1 byte zopfli --i10000 --mls16 --bsr9 --lazy --ohh November 30, 2019 @ 00:51
53434 bytes -1 byte zopfli --i10000 --mls128 --bsr9 --lazy --ohh November 30, 2019 @ 00:06
53435 bytes -1 byte zopfli --i10000 --mls32 --bsr11 --lazy --ohh November 29, 2019 @ 23:45
53436 bytes -2 bytes zopfli --i10000 --mls32 --bsr12 --lazy --ohh November 29, 2019 @ 23:27
53438 bytes -2 bytes zopfli --i1000 --mls8192 --bsr9 --lazy --ohh November 29, 2019 @ 21:09
53440 bytes -3 bytes zopfli --i1000 --mls4 --bsr11 --lazy --ohh November 29, 2019 @ 20:25
53443 bytes -2 bytes zopfli --i1000 --mls8 --bsr21 --lazy --ohh November 29, 2019 @ 20:24
53445 bytes zopfli --i100 --mls128 --bsr30 --lazy --ohh November 29, 2019 @ 19:39

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

Most recent activity on December 2, 2019 @ 16:35.

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
53470 53432 53434 53433 53434 53434 53434 53431 53455 53447 53437 53436 53439 53470 53456
53464 53468 53438 53434 53437 53446 53434 53433 53443 53436 53456 53440 53438 53443 53439
53469 53480 53433 53438 53438 53445 53429 53444 53444 53444 53447 53456 53441 53451 53447
53465 53469 53437 53466 53432 53440 53440 53441 53441 53438 53449 53440 53441 53446 53440
53460 53466 53464 53467 53432 53442 53433 53432 53452 53443 53457 53434 53435 53452 53448
53445 53464 53432 53433 53432 53436 53434 53426 53441 53442 53446 53434 53432 53456 53442
53478 53433 53436 53468 53435 53433 53443 53432 53446 53442 53444 53440 53434 53451 53443
53431 53431 53435 53432 53435 53440 53434 53432 53441 53442 53444 53433 53441 53441 53443
53465 53468 53464 53440 53436 53432 53433 53426 53441 53443 53448 53440 53440 53447 53441
53465 53465 53432 53450 53443 53440 53431 53433 53441 53442 53444 53440 53438 53451 53448
53432 53474 53479 53469 53436 53436 53425 53442 53447 53445 53444 53438 53445 53450 53445
53464 53469 53431 53435 53447 53443 53426 53433 53442 53442 53456 53441 53433 53454 53445
53463 53467 53461 53474 53433 53448 53431 53444 53440 53444 53445 53448 53443 53442 53440
53466 53473 53475 53482 53432 53443 53431 53442 53443 53443 53447 53453 53442 53442 53443
53464 53432 53432 53467 53435 53432 53431 53443 53443 53443 53446 53438 53441 53446 53453
53466 53433 53432 53435 53439 53441 53431 53433 53443 53443 53447 53454 53433 53455 53441
53466 53470 53432 53434 53435 53448 53431 53441 53441 53443 53454 53438 53434 53452 53452
53466 53470 53432 53468 53438 53435 53431 53432 53441 53443 53447 53433 53445 53451 53441
53462 53473 53435 53433 53433 53447 53431 53432 53443 53443 53445 53433 53441 53448 53442
53432 53436 53459 53434 53433 53440 53431 53442 53446 53440 53451 53435 53436 53443 53449
53463 53463 53432 53432 53433 53434 53431 53449 53445 53445 53445 53445 53447 53451 53447
53463 53468 53432 53433 53436 53443 53431 53433 53441 53442 53447 53453 53440 53452 53440
53464 53466 53437 53434 53435 53448 53427 53431 53441 53442 53444 53457 53441 53452 53443

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 53445 bytes 100%
1,000 53438 bytes -7 bytes 100%
10,000 53430 bytes -8 bytes 100%
100,000 53425 bytes -5 bytes 1.74%
1,000,000 53425 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
53596 bytes +171 bytes (+0.32%) +78 bytes
53518 bytes +93 bytes (+0.17%)
53541 bytes +116 bytes (+0.22%) +23 bytes
53574 bytes +149 bytes (+0.28%) +56 bytes
53596 bytes +171 bytes (+0.32%) +78 bytes
53612 bytes +187 bytes (+0.35%) +94 bytes
53599 bytes +174 bytes (+0.33%) +81 bytes
53637 bytes +212 bytes (+0.40%) +119 bytes
53668 bytes +243 bytes (+0.45%) +150 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 39276 bytes -14149 bytes (-26.48%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 46902 bytes -6523 bytes (-12.21%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 47824 bytes -5601 bytes (-10.48%)
Brotli (Wikipedia) brotli brotli -q 11 49335 bytes -4090 bytes (-7.66%)
LZMA2 (Wikipedia) xz xz -9 50424 bytes -3001 bytes (-5.62%)
Zstandard (Wikipedia) zstd zstd -19 51750 bytes -1675 bytes (-3.14%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 52078 bytes -1347 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.