BackboneJS 0.3.3 - as small as it gets (near-perfect GZIP compression)

The original file has 35706 bytes (34.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 11550 bytes (11.3k, 32%).

After GZIP compression these minified files vary in size:

Boot	4424 bytes (4.3k)	CDN
Baidu	3975 bytes (3.9k)	CDN
cdnjs	3958 bytes (3.9k)	CDN
gzip -6 (default)	3954 bytes (3.9k)	local copy
gzip -9	3952 bytes (3.9k)	local copy
unpkg	3931 bytes (3.8k)	CDN
libdeflate -12	3848 bytes (3.8k)	local copy
zultra	3846 bytes (3.8k)	local copy
7zip -mx=9 -tgzip	3843 bytes (3.8k)	local copy
pigz -11 -n	3843 bytes (3.8k)	local copy
kzip -s0 -rn -b0	3842 bytes (3.8k)	local copy
Zopfli	3839 bytes (3.7k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.3.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 0.3.3 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 92 bytes by using my BackboneJS 0.3.3 Zopfli version instead of the best available CDN (2.40% smaller than unpkg, 3839 vs. 3931 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 --i1000 --mb8 --mls2048 --bsr2 --lazy --ohh

(found September 8, 2015)

Description	Value	Parameter
iterations	1000	--i1000
maximum blocks	8	--mb8
maximum length score	2048	--mls2048
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

Verify file integrity

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

MD5:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.3.3/backbone-min.js --location | md5sum
5c8053a6fab598f46af8d7e59bfc0ce1 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.3.min.zopfli.js.gz | md5sum
5c8053a6fab598f46af8d7e59bfc0ce1 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.3.3/backbone-min.js --location | sha1sum
f29dc890697e78d412a5e06da3623c76cbd80b07 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.3.min.zopfli.js.gz | sha1sum
f29dc890697e78d412a5e06da3623c76cbd80b07 -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	4424 bytes	5c8053a6fab598f46af8d7e59bfc0ce1	(invalid)
cdnjs	3958 bytes	5c8053a6fab598f46af8d7e59bfc0ce1	(invalid)
unpkg	3931 bytes	5c8053a6fab598f46af8d7e59bfc0ce1	July 11, 2016 @ 16:18

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
Baidu	3975 bytes	5d7dc1cbe7f0b177cf66187937001fb9	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
3839 bytes	-1 byte	zopfli --i1000 --mls2048 --bsr2 --lazy --ohh	September 8, 2015 @ 11:49
3840 bytes	-2 bytes	zopfli --i1000 --mls512 --bsr9 --lazy --ohh	September 8, 2015 @ 11:49
3842 bytes	–	zopfli --i100 --mls512 --bsr14 --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, 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	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
4	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
6	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
7	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
8	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3846	3846
9	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
10	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
11	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3846	3846
12	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
13	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
14	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
15	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
16	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3846	3846
17	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
18	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
19	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
20	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
21	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
22	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
23	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
25	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
30	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840
40	3840	3840	3840	3840	3840	3840	3840	3840	3840	3840	3839	3840	3840	3840	3840

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	3842 bytes	–	100%
1,000	3839 bytes	-3 bytes	100%
10,000	3839 bytes	–	100%
100,000	3839 bytes	–	6.67%
1,000,000	3839 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)	3842 bytes	+3 bytes (+0.08%)	–
1	3842 bytes	+3 bytes (+0.08%)	–
2	3868 bytes	+29 bytes (+0.76%)	+26 bytes
3	3907 bytes	+68 bytes (+1.77%)	+65 bytes
4	3922 bytes	+83 bytes (+2.16%)	+80 bytes
5	3952 bytes	+113 bytes (+2.94%)	+110 bytes
6	3991 bytes	+152 bytes (+3.96%)	+149 bytes
7	4023 bytes	+184 bytes (+4.79%)	+181 bytes
8	4064 bytes	+225 bytes (+5.86%)	+222 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	3440 bytes	-399 bytes (-10.39%)
Brotli (Wikipedia)	brotli	brotli -q 11	3453 bytes	-386 bytes (-10.05%)
Zstandard (Wikipedia)	zstd	zstd -19	3863 bytes	+24 bytes (+0.63%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	3879 bytes	+40 bytes (+1.04%)
LZMA2 (Wikipedia)	xz	xz -9	3916 bytes	+77 bytes (+2.01%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	3926 bytes	+87 bytes (+2.27%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	4275 bytes	+436 bytes (+11.36%)

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.