BackboneJS 0.1.2 - as small as it gets (near-perfect GZIP compression)

The original file has 23824 bytes (23.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 7655 bytes (7.5k, 32%).

After GZIP compression these minified files vary in size:

Boot	2909 bytes (2.8k)	CDN
gzip -6 (default)	2631 bytes (2.6k)	local copy
gzip -9	2628 bytes (2.6k)	local copy
cdnjs	2625 bytes (2.6k)	CDN
unpkg	2607 bytes (2.5k)	CDN
libdeflate -12	2557 bytes (2.5k)	local copy
7zip -mx=9 -tgzip	2553 bytes (2.5k)	local copy
kzip -s0 -rn -b1	2553 bytes (2.5k)	local copy
pigz -11 -n	2553 bytes (2.5k)	local copy
Zopfli	2552 bytes (2.5k)	local copy
zultra	2552 bytes (2.5k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-0.1.2.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 0.1.2 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 55 bytes by using my BackboneJS 0.1.2 Zopfli version instead of the best available CDN (2.16% smaller than unpkg, 2552 vs. 2607 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 --i100 --mb8 --mls2048 --bsr2 --lazy --ohh

(found September 8, 2015)

Description	Value	Parameter
iterations	100	--i100
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/0.1.2/backbone-min.js --location | md5sum
baca4f0f379ca7728549143ef52740c8 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.1.2.min.zopfli.js.gz | md5sum
baca4f0f379ca7728549143ef52740c8 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.1.2/backbone-min.js --location | sha1sum
55dd76b5899e7f090d8d9f5286c48e7a593edd89 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.1.2.min.zopfli.js.gz | sha1sum
55dd76b5899e7f090d8d9f5286c48e7a593edd89 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	2909 bytes	baca4f0f379ca7728549143ef52740c8	(invalid)
cdnjs	2625 bytes	baca4f0f379ca7728549143ef52740c8	(invalid)
unpkg	2607 bytes	baca4f0f379ca7728549143ef52740c8	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
2552 bytes	–	zopfli --i100 --mls2048 --bsr2 --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 @ 12:47.

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 100,000.

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	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
4	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
6	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
7	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
8	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
9	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
10	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
11	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
12	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
13	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
14	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
15	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
16	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
17	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
18	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
19	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
20	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
21	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
22	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
23	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
25	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
30	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553
40	2553	2553	2553	2553	2553	2553	2552	2552	2553	2553	2552	2553	2553	2553	2553

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	2552 bytes	–	100%
1,000	2552 bytes	–	100%
10,000	2552 bytes	–	100%
100,000	2552 bytes	–	20.00%
1,000,000	–	–	–
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)	2553 bytes	+1 byte (+0.04%)	–
1	2553 bytes	+1 byte (+0.04%)	–
2	2588 bytes	+36 bytes (+1.41%)	+35 bytes
3	2619 bytes	+67 bytes (+2.63%)	+66 bytes
4	2657 bytes	+105 bytes (+4.11%)	+104 bytes
5	2697 bytes	+145 bytes (+5.68%)	+144 bytes
6	2732 bytes	+180 bytes (+7.05%)	+179 bytes
7	2756 bytes	+204 bytes (+7.99%)	+203 bytes
8	2789 bytes	+237 bytes (+9.29%)	+236 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	2301 bytes	-251 bytes (-9.84%)
Brotli (Wikipedia)	brotli	brotli -q 11	2326 bytes	-226 bytes (-8.86%)
Zstandard (Wikipedia)	zstd	zstd -19	2581 bytes	+29 bytes (+1.14%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	2619 bytes	+67 bytes (+2.63%)
LZMA2 (Wikipedia)	xz	xz -9	2656 bytes	+104 bytes (+4.08%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	2893 bytes	+341 bytes (+13.36%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	3202 bytes	+650 bytes (+25.47%)

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.