BackboneJS 0.3.0 - as small as it gets (near-perfect GZIP compression)

The original file has 33589 bytes (32.8k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 10907 bytes (10.7k, 32%).

After GZIP compression these minified files vary in size:

Boot	4193 bytes (4.1k)	CDN
cdnjs	3746 bytes (3.7k)	CDN
gzip -6 (default)	3745 bytes (3.7k)	local copy
gzip -9	3744 bytes (3.7k)	local copy
unpkg	3724 bytes (3.6k)	CDN
libdeflate -12	3649 bytes (3.6k)	local copy
zultra	3646 bytes (3.6k)	local copy
7zip -mx=9 -tgzip	3643 bytes (3.6k)	local copy
kzip -s0 -rn -b1	3641 bytes (3.6k)	local copy
pigz -11 -n	3641 bytes (3.6k)	local copy
Zopfli	3639 bytes (3.6k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.0.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 0.3.0 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 85 bytes by using my BackboneJS 0.3.0 Zopfli version instead of the best available CDN (2.34% smaller than unpkg, 3639 vs. 3724 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 --mls512 --bsr8 --lazy --ohh

(found November 27, 2015)

Description	Value	Parameter
iterations	1000000	--i1000000
maximum blocks	8	--mb8
maximum length score	512	--mls512
block splitting recursion	8	--bsr8
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/0.3.0/backbone-min.js --location | md5sum
5d10787d656341eef98bd0eb99a33f73 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.0.min.zopfli.js.gz | md5sum
5d10787d656341eef98bd0eb99a33f73 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.3.0/backbone-min.js --location | sha1sum
c1d4b6a42a7e8946494c095fe253adf8e8161e65 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.0.min.zopfli.js.gz | sha1sum
c1d4b6a42a7e8946494c095fe253adf8e8161e65 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	4193 bytes	5d10787d656341eef98bd0eb99a33f73	(invalid)
cdnjs	3746 bytes	5d10787d656341eef98bd0eb99a33f73	(invalid)
unpkg	3724 bytes	5d10787d656341eef98bd0eb99a33f73	July 11, 2016 @ 16:18

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
3639 bytes	-1 byte	zopfli --i1000000 --mls512 --bsr8 --lazy --ohh	November 27, 2015 @ 13:46
3640 bytes	–	zopfli --i100 --mls512 --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 @ 12:49.

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:
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
2	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
4	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
6	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
7	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
8	3640	3640	3640	3640	3640	3640	3640	3640	3639	3640	3640	3640	3640	3640	3640
9	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
10	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
11	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
12	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
13	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
14	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
15	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
16	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
17	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
18	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
19	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
20	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
21	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
22	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
23	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
25	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
30	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640
40	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640	3640

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	3640 bytes	–	100%
1,000	3640 bytes	–	100%
10,000	3640 bytes	–	100%
100,000	3640 bytes	–	100%
1,000,000	3639 bytes	-1 byte	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)	3641 bytes	+2 bytes (+0.05%)	–
1	3641 bytes	+2 bytes (+0.05%)	–
2	3668 bytes	+29 bytes (+0.80%)	+27 bytes
3	3707 bytes	+68 bytes (+1.87%)	+66 bytes
4	3720 bytes	+81 bytes (+2.23%)	+79 bytes
5	3760 bytes	+121 bytes (+3.33%)	+119 bytes
6	3800 bytes	+161 bytes (+4.42%)	+159 bytes
7	3832 bytes	+193 bytes (+5.30%)	+191 bytes
8	3862 bytes	+223 bytes (+6.13%)	+221 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
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	3265 bytes	-374 bytes (-10.28%)
Brotli (Wikipedia)	brotli	brotli -q 11	3290 bytes	-349 bytes (-9.59%)
Zstandard (Wikipedia)	zstd	zstd -19	3658 bytes	+19 bytes (+0.52%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	3680 bytes	+41 bytes (+1.13%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	3712 bytes	+73 bytes (+2.01%)
LZMA2 (Wikipedia)	xz	xz -9	3720 bytes	+81 bytes (+2.23%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	4105 bytes	+466 bytes (+12.81%)

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 2026.
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.