BackboneJS 0.3.2 - as small as it gets (near-perfect GZIP compression)

The original file has 34669 bytes (33.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 11153 bytes (10.9k, 32%).

After GZIP compression these minified files vary in size:

Boot	4255 bytes (4.2k)	CDN
gzip -6 (default)	3820 bytes (3.7k)	local copy
gzip -9	3816 bytes (3.7k)	local copy
cdnjs	3815 bytes (3.7k)	CDN
unpkg	3792 bytes (3.7k)	CDN
libdeflate -12	3716 bytes (3.6k)	local copy
zultra	3714 bytes (3.6k)	local copy
7zip -mx=9 -tgzip	3710 bytes (3.6k)	local copy
pigz -11 -n	3709 bytes (3.6k)	local copy
kzip -s0 -rn -b1	3708 bytes (3.6k)	local copy
Zopfli	3707 bytes (3.6k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.2.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 0.3.2 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 85 bytes by using my BackboneJS 0.3.2 Zopfli version instead of the best available CDN (2.29% smaller than unpkg, 3707 vs. 3792 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 --i10000 --mb8 --mls512 --bsr2 --lazy --ohh

(found September 8, 2015)

Description	Value	Parameter
iterations	10000	--i10000
maximum blocks	8	--mb8
maximum length score	512	--mls512
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/0.3.2/backbone-min.js --location | md5sum
2b86430594cc9ce4439fd2e9fc8baa56 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.2.min.zopfli.js.gz | md5sum
2b86430594cc9ce4439fd2e9fc8baa56 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.3.2/backbone-min.js --location | sha1sum
768517dc26c24579b8b44ab6761bae9aa5b98b08 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.3.2.min.zopfli.js.gz | sha1sum
768517dc26c24579b8b44ab6761bae9aa5b98b08 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	4255 bytes	2b86430594cc9ce4439fd2e9fc8baa56	(invalid)
cdnjs	3815 bytes	2b86430594cc9ce4439fd2e9fc8baa56	(invalid)
unpkg	3792 bytes	2b86430594cc9ce4439fd2e9fc8baa56	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
3707 bytes	-1 byte	zopfli --i10000 --mls512 --bsr2 --lazy --ohh	September 8, 2015 @ 14:15
3708 bytes	–	zopfli --i100 --mls2048 --bsr2 --lazy --ohh	September 8, 2015 @ 11:32

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 @ 12:50.

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	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
4	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
6	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
7	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
8	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
9	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
10	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
11	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
12	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
13	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
14	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
15	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
16	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
17	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
18	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
19	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
20	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
21	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
22	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
23	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
25	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
30	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708
40	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3707	3708	3708

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	3708 bytes	–	100%
1,000	3708 bytes	–	100%
10,000	3707 bytes	-1 byte	100%
100,000	3707 bytes	–	86.67%
1,000,000	3707 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)	3708 bytes	+1 byte (+0.03%)	–
1	3708 bytes	+1 byte (+0.03%)	–
2	3733 bytes	+26 bytes (+0.70%)	+25 bytes
3	3772 bytes	+65 bytes (+1.75%)	+64 bytes
4	3786 bytes	+79 bytes (+2.13%)	+78 bytes
5	3815 bytes	+108 bytes (+2.91%)	+107 bytes
6	3853 bytes	+146 bytes (+3.94%)	+145 bytes
7	3891 bytes	+184 bytes (+4.96%)	+183 bytes
8	3926 bytes	+219 bytes (+5.91%)	+218 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	3316 bytes	-391 bytes (-10.55%)
Brotli (Wikipedia)	brotli	brotli -q 11	3345 bytes	-362 bytes (-9.77%)
Zstandard (Wikipedia)	zstd	zstd -19	3732 bytes	+25 bytes (+0.67%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	3767 bytes	+60 bytes (+1.62%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	3779 bytes	+72 bytes (+1.94%)
LZMA2 (Wikipedia)	xz	xz -9	3788 bytes	+81 bytes (+2.19%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	4155 bytes	+448 bytes (+12.09%)

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.