BackboneJS 1.1.0 - as small as it gets (near-perfect GZIP compression)

The original file has 60127 bytes (58.7k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 19548 bytes (19.1k, 33%).

After GZIP compression these minified files vary in size:

Boot	7490 bytes (7.3k)	CDN
Baidu	6527 bytes (6.4k)	CDN
cdnjs	6524 bytes (6.4k)	CDN
gzip -6 (default)	6514 bytes (6.4k)	local copy
gzip -9	6504 bytes (6.4k)	local copy
unpkg	6487 bytes (6.3k)	CDN
Yandex	6482 bytes (6.3k)	CDN
jsdelivr	6482 bytes (6.3k)	CDN
libdeflate -12	6324 bytes (6.2k)	local copy
zultra	6323 bytes (6.2k)	local copy
7zip -mx=9 -tgzip	6321 bytes (6.2k)	local copy
pigz -11 -n	6316 bytes (6.2k)	local copy
kzip -s0 -rn -b1	6314 bytes (6.2k)	local copy
Zopfli	6311 bytes (6.2k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-1.1.0.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 1.1.0 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 171 bytes by using my BackboneJS 1.1.0 Zopfli version instead of the best available CDN (2.71% smaller than jsdelivr, 6311 vs. 6482 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 --i100000 --mb8 --mls8 --bsr15 --lazy --ohh

(found November 27, 2015)

Description	Value	Parameter
iterations	100000	--i100000
maximum blocks	8	--mb8
maximum length score	8	--mls8
block splitting recursion	15	--bsr15
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/1.1.0/backbone-min.js --location | md5sum
dd2e6c2643968f7932487454302f407d -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-1.1.0.min.zopfli.js.gz | md5sum
dd2e6c2643968f7932487454302f407d -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/1.1.0/backbone-min.js --location | sha1sum
7c9117d7f9bc38159c7687a1b41b42a5c7d4e63f -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-1.1.0.min.zopfli.js.gz | sha1sum
7c9117d7f9bc38159c7687a1b41b42a5c7d4e63f -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	7490 bytes	dd2e6c2643968f7932487454302f407d	(invalid)
cdnjs	6524 bytes	dd2e6c2643968f7932487454302f407d	(invalid)
unpkg	6487 bytes	dd2e6c2643968f7932487454302f407d	July 11, 2016 @ 16:18
Yandex	6482 bytes	dd2e6c2643968f7932487454302f407d	(invalid)
jsdelivr	6482 bytes	dd2e6c2643968f7932487454302f407d	(invalid)

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
Baidu	6527 bytes	19adb37ed9f0968ced67889ba9f5f553	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
6311 bytes	-1 byte	zopfli --i100000 --mls8 --bsr15 --lazy --ohh	November 27, 2015 @ 17:44
6312 bytes	-1 byte	zopfli --i10000 --mls512 --bsr8 --lazy --ohh	September 8, 2015 @ 12:54
6313 bytes	–	zopfli --i100 --mls512 --bsr4 --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 @ 12:43.

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	6317	6318	6317	6317	6311	6313	6317	6318	6316	6313	6318	6317	6318	6317	6317
4	6322	6317	6320	6320	6312	6315	6315	6321	6312	6314	6318	6313	6314	6313	6313
6	6312	6317	6313	6312	6312	6315	6315	6314	6314	6313	6315	6313	6313	6312	6313
7	6316	6317	6313	6315	6312	6315	6312	6315	6316	6312	6314	6315	6312	6313	6312
8	6313	6318	6311	6315	6312	6315	6315	6314	6312	6312	6314	6317	6313	6313	6313
9	6312	6313	6313	6315	6315	6315	6318	6319	6316	6314	6314	6316	6313	6313	6313
10	6315	6317	6313	6312	6312	6312	6315	6315	6315	6312	6315	6315	6314	6313	6313
11	6316	6317	6315	6315	6313	6315	6317	6321	6312	6317	6315	6315	6313	6313	6313
12	6313	6312	6313	6312	6312	6315	6315	6314	6312	6317	6315	6315	6312	6313	6313
13	6324	6317	6311	6314	6312	6312	6315	6312	6312	6317	6316	6317	6313	6313	6312
14	6315	6317	6318	6312	6312	6313	6315	6314	6314	6313	6315	6315	6314	6313	6313
15	6315	6317	6311	6315	6313	6313	6315	6314	6316	6313	6313	6315	6314	6315	6313
16	6312	6317	6311	6312	6312	6315	6315	6314	6314	6312	6315	6317	6312	6313	6312
17	6317	6317	6318	6318	6313	6318	6318	6314	6316	6313	6313	6315	6312	6313	6313
18	6312	6316	6313	6315	6316	6315	6315	6314	6315	6312	6315	6315	6312	6313	6313
19	6312	6317	6313	6315	6316	6315	6318	6320	6315	6312	6314	6315	6314	6313	6313
20	6312	6317	6311	6312	6312	6318	6318	6319	6312	6314	6315	6315	6313	6313	6313
21	6316	6317	6311	6315	6313	6315	6315	6314	6315	6312	6315	6315	6313	6313	6313
22	6312	6317	6311	6315	6312	6315	6315	6320	6312	6312	6315	6315	6313	6312	6313
23	6312	6317	6318	6312	6312	6313	6315	6312	6314	6312	6314	6317	6314	6313	6313
25	6312	6317	6311	6315	6312	6315	6315	6314	6315	6318	6313	6315	6312	6313	6313
30	6313	6317	6313	6316	6313	6315	6316	6313	6315	6312	6315	6315	6314	6313	6312
40	6312	6316	6313	6316	6313	6313	6317	6321	6312	6312	6317	6315	6313	6313	6312

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	6313 bytes	–	100%
1,000	6313 bytes	–	100%
10,000	6312 bytes	-1 byte	100%
100,000	6311 bytes	-1 byte	22.32%
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)	6314 bytes	+3 bytes (+0.05%)	–
1	6314 bytes	+3 bytes (+0.05%)	–
2	6340 bytes	+29 bytes (+0.46%)	+26 bytes
3	6373 bytes	+62 bytes (+0.98%)	+59 bytes
4	6410 bytes	+99 bytes (+1.57%)	+96 bytes
5	6425 bytes	+114 bytes (+1.81%)	+111 bytes
6	6446 bytes	+135 bytes (+2.14%)	+132 bytes
7	6480 bytes	+169 bytes (+2.68%)	+166 bytes
8	6515 bytes	+204 bytes (+3.23%)	+201 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	5523 bytes	-788 bytes (-12.49%)
Brotli (Wikipedia)	brotli	brotli -q 11	5870 bytes	-441 bytes (-6.99%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5937 bytes	-374 bytes (-5.93%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	6260 bytes	-51 bytes (-0.81%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	6292 bytes	-19 bytes (-0.30%)
Zstandard (Wikipedia)	zstd	zstd -19	6323 bytes	+12 bytes (+0.19%)
LZMA2 (Wikipedia)	xz	xz -9	6364 bytes	+53 bytes (+0.84%)

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.