Choose a version:
21% The original file has 316419 bytes (309.0k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 67947 bytes (66.4k, 21%).

After GZIP compression these minified files vary in size:
unpkg
  29224 bytes (28.5k)
CDN
Boot
  25223 bytes (24.6k)
CDN
cdnjs
  25223 bytes (24.6k)
CDN
gzip -6 (default)
  24993 bytes (24.4k)
local copy
gzip -9
  24948 bytes (24.4k)
local copy
7zip -mx=9 -tgzip
  24192 bytes (23.6k)
local copy
libdeflate -12
  24163 bytes (23.6k)
local copy
kzip -s0 -rn -b4
  24143 bytes (23.6k)
local copy
pigz -11 -n
  24132 bytes (23.6k)
local copy
Zopfli
  24109 bytes (23.5k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/knockout/knockout-3.5.0.min.js (or via HTTPS)

You will automatically get the smallest Knockout 3.5.0 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

Save 1114 bytes by using my Knockout 3.5.0 Zopfli version instead of the best available CDN (4.62% smaller than cdnjs, 24109 vs. 25223 bytes):
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 --mls32768 --bsr25 --lazy --ohh

(found February 25, 2019)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 32768  --mls32768
block splitting recursion 25  --bsr25
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

Verify file integrity

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

MD5:
curl --silent --compressed https://knockoutjs.com/downloads/knockout-3.5.0.js --location | md5sum
7e1181f8f921eee112269c7cebf56253  -
curl --silent --compressed https://minime.stephan-brumme.com/files/knockout/knockout-3.5.0.min.zopfli.js.gz | md5sum
7e1181f8f921eee112269c7cebf56253  -

SHA1:
curl --silent --compressed https://knockoutjs.com/downloads/knockout-3.5.0.js --location | sha1sum
f84683eaf02fed494b121b314f41c0756183a0bd  -
curl --silent --compressed https://minime.stephan-brumme.com/files/knockout/knockout-3.5.0.min.zopfli.js.gz | sha1sum
f84683eaf02fed494b121b314f41c0756183a0bd  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
unpkg 29224 bytes 7e1181f8f921eee112269c7cebf56253 (invalid)
Boot 25223 bytes 7e1181f8f921eee112269c7cebf56253 February 24, 2019 @ 10:15
cdnjs 25223 bytes 7e1181f8f921eee112269c7cebf56253 February 24, 2019 @ 10:15

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

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

3.5.0,
3.4.2, 3.4.1, 3.4.0,
3.3.0,
3.2.0,
3.1.0,
3.0.0,
2.3.0,
2.2.1, 2.2.0,
2.1.0,
2.0.0,
1.2.1, 1.2.0,
1.1.2, 1.1.1, 1.1.0

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Dojo, Ember, jQuery, lodash, React, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
24109 bytes -1 byte zopfli --i100000 --mls32768 --bsr25 --lazy --ohh February 25, 2019 @ 07:50
24110 bytes -2 bytes zopfli --i10000 --mls32768 --bsr25 --lazy --ohh February 23, 2019 @ 04:09
24112 bytes -1 byte zopfli --i10000 --mls4096 --bsr6 --lazy --ohh February 22, 2019 @ 21:16
24113 bytes -1 byte zopfli --i10000 --mls32768 --bsr6 --lazy --ohh February 22, 2019 @ 16:14
24114 bytes -2 bytes zopfli --i1000 --mls4096 --bsr7 --lazy --ohh February 22, 2019 @ 13:48
24116 bytes -1 byte zopfli --i1000 --mls4096 --bsr10 --lazy --ohh February 22, 2019 @ 12:46
24117 bytes zopfli --i100 --mls32768 --bsr14 --lazy --ohh February 22, 2019 @ 11:00

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 @ 13:18.

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
24121 24120 24119 24122 24122 24122 24120 24120 24122 24122 24123 24119 24118 24133 24118
24117 24121 24121 24124 24121 24123 24123 24121 24119 24118 24121 24118 24124 24127 24113
24118 24121 24118 24119 24117 24120 24119 24121 24119 24118 24123 24112 24126 24124 24113
24119 24118 24120 24121 24120 24120 24118 24118 24120 24120 24118 24112 24129 24124 24112
24121 24119 24122 24122 24119 24120 24121 24120 24117 24118 24118 24116 24127 24123 24116
24117 24120 24118 24117 24121 24120 24119 24118 24117 24121 24118 24116 24116 24123 24125
24118 24121 24126 24119 24117 24121 24122 24120 24123 24118 24117 24113 24128 24127 24114
24121 24119 24118 24119 24120 24120 24119 24121 24118 24118 24117 24114 24127 24124 24115
24119 24121 24121 24117 24119 24120 24120 24121 24117 24118 24118 24115 24126 24129 24128
24118 24121 24121 24119 24117 24120 24123 24121 24119 24118 24118 24114 24114 24123 24125
24118 24119 24119 24117 24118 24120 24118 24121 24121 24119 24118 24116 24127 24123 24116
24119 24119 24118 24117 24117 24120 24119 24121 24120 24118 24117 24114 24127 24128 24115
24117 24119 24118 24119 24117 24118 24122 24121 24117 24118 24118 24114 24127 24123 24114
24117 24120 24121 24119 24119 24121 24120 24121 24117 24117 24118 24116 24127 24123 24115
24118 24119 24118 24119 24120 24120 24122 24121 24117 24118 24120 24116 24127 24125 24117
24117 24118 24126 24118 24120 24120 24119 24118 24117 24119 24118 24116 24122 24125 24125
24118 24118 24120 24121 24120 24120 24123 24120 24117 24118 24118 24116 24127 24123 24115
24118 24121 24118 24117 24120 24117 24123 24121 24118 24118 24118 24114 24123 24129 24119
24118 24119 24119 24127 24120 24120 24123 24118 24119 24118 24118 24116 24122 24124 24124
24120 24120 24119 24119 24121 24120 24118 24121 24117 24119 24118 24116 24116 24125 24110
24117 24119 24119 24117 24120 24120 24120 24121 24117 24119 24118 24113 24123 24128 24109
24117 24119 24127 24117 24117 24121 24120 24121 24117 24118 24117 24114 24115 24128 24123
24117 24119 24118 24119 24117 24120 24123 24121 24119 24119 24118 24116 24127 24124 24113

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 24117 bytes 100%
1,000 24114 bytes -3 bytes 100%
10,000 24110 bytes -4 bytes 100%
100,000 24109 bytes -1 byte 0.58%
1,000,000 24109 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
24207 bytes +98 bytes (+0.41%) +64 bytes
24207 bytes +98 bytes (+0.41%) +64 bytes
24167 bytes +58 bytes (+0.24%) +24 bytes
24159 bytes +50 bytes (+0.21%) +16 bytes
24143 bytes +34 bytes (+0.14%)
24171 bytes +62 bytes (+0.26%) +28 bytes
24200 bytes +91 bytes (+0.38%) +57 bytes
24246 bytes +137 bytes (+0.57%) +103 bytes
24291 bytes +182 bytes (+0.75%) +148 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 20192 bytes -3917 bytes (-16.25%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 20307 bytes -3802 bytes (-15.77%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 20392 bytes -3717 bytes (-15.42%)
Brotli (Wikipedia) brotli brotli -q 11 22160 bytes -1949 bytes (-8.08%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 22597 bytes -1512 bytes (-6.27%)
LZMA2 (Wikipedia) xz xz -9 23528 bytes -581 bytes (-2.41%)
Zstandard (Wikipedia) zstd zstd -19 23880 bytes -229 bytes (-0.95%)

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