BackboneJS 0.9.2 - as small as it gets (near-perfect GZIP compression)

The original file has 53103 bytes (51.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 16464 bytes (16.1k, 31%).

After GZIP compression these minified files vary in size:

Boot	6542 bytes (6.4k)	CDN
Baidu	5827 bytes (5.7k)	CDN
cdnjs	5797 bytes (5.7k)	CDN
gzip -6 (default)	5782 bytes (5.6k)	local copy
gzip -9	5779 bytes (5.6k)	local copy
unpkg	5767 bytes (5.6k)	CDN
libdeflate -12	5631 bytes (5.5k)	local copy
7zip -mx=9 -tgzip	5626 bytes (5.5k)	local copy
zultra	5624 bytes (5.5k)	local copy
pigz -11 -n	5622 bytes (5.5k)	local copy
kzip -s0 -rn -b0	5620 bytes (5.5k)	local copy
Zopfli	5609 bytes (5.5k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-0.9.2.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 0.9.2 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 158 bytes by using my BackboneJS 0.9.2 Zopfli version instead of the best available CDN (2.82% smaller than unpkg, 5609 vs. 5767 bytes):

Download

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 --mls8192 --bsr22 --lazy --ohh

(found November 27, 2015)

Description	Value	Parameter
iterations	1000000	--i1000000
maximum blocks	8	--mb8
maximum length score	8192	--mls8192
block splitting recursion	22	--bsr22
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://raw.githubusercontent.com/jashkenas/backbone/0.9.2/backbone-min.js --location | md5sum
9f8b43fd1df78dca0827c73e29890865 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.9.2.min.zopfli.js.gz | md5sum
9f8b43fd1df78dca0827c73e29890865 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.9.2/backbone-min.js --location | sha1sum
bdbfc587072f9af9100dd28e55e22911ed359df7 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.9.2.min.zopfli.js.gz | sha1sum
bdbfc587072f9af9100dd28e55e22911ed359df7 -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	6542 bytes	9f8b43fd1df78dca0827c73e29890865	(invalid)
cdnjs	5797 bytes	9f8b43fd1df78dca0827c73e29890865	(invalid)
unpkg	5767 bytes	9f8b43fd1df78dca0827c73e29890865	July 11, 2016 @ 16:18

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
Baidu	5827 bytes	49ff81bf752a77eb5a23ea10283b4bae	only whitespaces differ	(invalid)

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

Other Versions

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

1.4.1, 1.4.0,
1.3.3, 1.3.2, 1.3.1, 1.3.0,
1.2.3, 1.2.2, 1.2.1, 1.2.0,
1.1.2, 1.1.1, 1.1.0,
1.0.0,
0.9.10, 0.9.9, 0.9.2, 0.9.1, 0.9.0,
0.3.3, 0.3.2, 0.3.1, 0.3.0,
0.2.0,
0.1.2, 0.1.1

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

Changelog

Best Zopfli parameters so far:

Size	Improvement	Parameters	Found
5609 bytes	-2 bytes	zopfli --i1000000 --mls8192 --bsr22 --lazy --ohh	November 27, 2015 @ 14:35
5611 bytes	-1 byte	zopfli --i1000 --mls8192 --bsr22 --lazy --ohh	September 21, 2015 @ 23:58
5612 bytes	-1 byte	zopfli --i10000 --mls512 --bsr11 --lazy --ohh	September 8, 2015 @ 13:26
5613 bytes	-1 byte	zopfli --i1000 --mls512 --bsr11 --lazy --ohh	September 8, 2015 @ 11:46
5614 bytes	-1 byte	zopfli --i1000 --mls512 --bsr13 --lazy --ohh	September 8, 2015 @ 11:46
5615 bytes	–	zopfli --i100 --mls1024 --bsr8 --lazy --ohh	September 8, 2015 @ 11:31

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 @ 12:55.

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 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
2	5619	5619	5614	5619	5619	5614	5615	5616	5619	5619	5619	5614	5613	5612	5612
4	5619	5612	5616	5615	5616	5615	5614	5613	5619	5619	5619	5620	5613	5617	5617
6	5619	5614	5614	5615	5615	5613	5616	5612	5619	5613	5619	5619	5613	5614	5614
7	5619	5614	5616	5615	5614	5614	5615	5613	5613	5613	5619	5613	5613	5615	5615
8	5619	5617	5617	5615	5613	5613	5615	5613	5613	5612	5619	5620	5613	5612	5612
9	5619	5615	5616	5616	5615	5614	5616	5614	5614	5613	5619	5620	5616	5615	5615
10	5619	5614	5616	5616	5614	5616	5616	5612	5612	5613	5619	5613	5613	5616	5616
11	5619	5615	5616	5615	5616	5615	5616	5613	5612	5613	5619	5613	5613	5613	5613
12	5619	5614	5617	5615	5615	5615	5616	5613	5619	5612	5619	5613	5613	5614	5614
13	5619	5614	5614	5618	5613	5614	5613	5614	5612	5613	5619	5613	5613	5615	5615
14	5619	5612	5616	5616	5613	5612	5615	5612	5613	5619	5619	5620	5613	5615	5615
15	5619	5614	5617	5615	5615	5614	5613	5613	5613	5613	5619	5613	5613	5613	5613
16	5619	5615	5616	5616	5615	5616	5616	5619	5619	5613	5619	5613	5613	5613	5613
17	5619	5616	5616	5615	5612	5613	5615	5612	5619	5613	5619	5613	5613	5613	5613
18	5619	5614	5614	5615	5616	5612	5613	5614	5613	5612	5619	5619	5613	5613	5613
19	5619	5614	5616	5615	5615	5616	5616	5614	5613	5613	5619	5613	5613	5613	5613
20	5619	5614	5616	5615	5616	5615	5616	5614	5612	5612	5619	5619	5613	5613	5613
21	5619	5612	5616	5615	5616	5616	5616	5619	5619	5612	5619	5620	5613	5613	5613
22	5619	5614	5616	5612	5613	5616	5616	5612	5613	5613	5619	5613	5609	5613	5613
23	5619	5614	5612	5612	5613	5615	5612	5614	5613	5613	5619	5613	5613	5613	5613
25	5619	5617	5616	5615	5615	5615	5616	5612	5612	5613	5619	5619	5613	5613	5613
30	5619	5615	5616	5615	5616	5615	5616	5612	5619	5612	5619	5620	5613	5613	5613
40	5619	5612	5616	5616	5613	5612	5612	5613	5613	5619	5619	5613	5613	5615	5615

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	5613 bytes	–	100%
1,000	5611 bytes	-2 bytes	100%
10,000	5611 bytes	–	100%
100,000	5611 bytes	–	0.29%
1,000,000	5609 bytes	-2 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
(any)	5620 bytes	+11 bytes (+0.20%)	–
1	5620 bytes	+11 bytes (+0.20%)	–
2	5650 bytes	+41 bytes (+0.73%)	+30 bytes
3	5684 bytes	+75 bytes (+1.34%)	+64 bytes
4	5692 bytes	+83 bytes (+1.48%)	+72 bytes
5	5729 bytes	+120 bytes (+2.14%)	+109 bytes
6	5765 bytes	+156 bytes (+2.78%)	+145 bytes
7	5788 bytes	+179 bytes (+3.19%)	+168 bytes
8	5825 bytes	+216 bytes (+3.85%)	+205 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
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	4955 bytes	-654 bytes (-11.66%)
Brotli (Wikipedia)	brotli	brotli -q 11	5139 bytes	-470 bytes (-8.38%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5324 bytes	-285 bytes (-5.08%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	5607 bytes	-2 bytes (-0.04%)
Zstandard (Wikipedia)	zstd	zstd -19	5638 bytes	+29 bytes (+0.52%)
LZMA2 (Wikipedia)	xz	xz -9	5684 bytes	+75 bytes (+1.34%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	5782 bytes	+173 bytes (+3.08%)

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):

Load and Parse Data

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 2024.
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.