BackboneJS 1.0.0 - as small as it gets (near-perfect GZIP compression)

The original file has 59498 bytes (58.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 19457 bytes (19.0k, 33%).

After GZIP compression these minified files vary in size:

Boot	7480 bytes (7.3k)	CDN
unpkg	7349 bytes (7.2k)	CDN
Baidu	6462 bytes (6.3k)	CDN
cdnjs	6459 bytes (6.3k)	CDN
gzip -6 (default)	6455 bytes (6.3k)	local copy
gzip -9	6446 bytes (6.3k)	local copy
Sina	6433 bytes (6.3k)	CDN
Yandex	6425 bytes (6.3k)	CDN
jsdelivr	6425 bytes (6.3k)	CDN
zultra	6270 bytes (6.1k)	local copy
7zip -mx=9 -tgzip	6261 bytes (6.1k)	local copy
libdeflate -12	6261 bytes (6.1k)	local copy
pigz -11 -n	6257 bytes (6.1k)	local copy
kzip -s0 -rn -b0	6255 bytes (6.1k)	local copy
Zopfli	6248 bytes (6.1k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-1.0.0.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 1.0.0 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 177 bytes by using my BackboneJS 1.0.0 Zopfli version instead of the best available CDN (2.83% smaller than jsdelivr, 6248 vs. 6425 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 --mls16384 --bsr21 --lazy --ohh

(found November 18, 2015)

Description	Value	Parameter
iterations	10000	--i10000
maximum blocks	8	--mb8
maximum length score	16384	--mls16384
block splitting recursion	21	--bsr21
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/1.0.0/backbone-min.js --location | md5sum
9cfbc78dc7eb8ac72cc3af1bec8ce7ee -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-1.0.0.min.zopfli.js.gz | md5sum
9cfbc78dc7eb8ac72cc3af1bec8ce7ee -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/1.0.0/backbone-min.js --location | sha1sum
89218fd4c321457a82aac6e4d3b5a50088745155 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-1.0.0.min.zopfli.js.gz | sha1sum
89218fd4c321457a82aac6e4d3b5a50088745155 -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	7480 bytes	9cfbc78dc7eb8ac72cc3af1bec8ce7ee	(invalid)
cdnjs	6459 bytes	9cfbc78dc7eb8ac72cc3af1bec8ce7ee	(invalid)
Sina	6433 bytes	9cfbc78dc7eb8ac72cc3af1bec8ce7ee	(invalid)
Yandex	6425 bytes	9cfbc78dc7eb8ac72cc3af1bec8ce7ee	(invalid)
jsdelivr	6425 bytes	9cfbc78dc7eb8ac72cc3af1bec8ce7ee	(invalid)

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
unpkg	7349 bytes	f18da2d38e372f6a594537c9ef7fb347	< (function(){var t=this;var e=t.Backbone;var i=[];var r=i.p [...] > (function(){var root=this;var previousBackbone=root.Backbo [...]	July 11, 2016 @ 16:18
Baidu	6462 bytes	52a3911cc70c2b120b670eb73d0f7a5f	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
6248 bytes	-1 byte	zopfli --i10000 --mls16384 --bsr21 --lazy --ohh	November 18, 2015 @ 02:53
6249 bytes	-2 bytes	zopfli --i1000 --mls8192 --bsr9 --lazy --ohh	September 8, 2015 @ 14:59
6251 bytes	-1 byte	zopfli --i1000 --mls1024 --bsr10 --lazy --ohh	September 8, 2015 @ 14:58
6252 bytes	–	zopfli --i100 --mls1024 --bsr6 --lazy --ohh	September 8, 2015 @ 14:57

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 @ 12:52.

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 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	6254	6254	6253	6253	6253	6253	6255	6254	6251	6255	6253	6253	6253	6253	6253
4	6253	6253	6249	6253	6253	6251	6259	6259	6251	6252	6254	6254	6249	6249	6249
6	6253	6252	6251	6252	6255	6251	6253	6253	6252	6251	6253	6251	6250	6252	6253
7	6253	6253	6253	6250	6251	6251	6255	6253	6252	6251	6253	6250	6249	6249	6249
8	6254	6252	6255	6253	6255	6254	6251	6254	6252	6252	6254	6250	6249	6249	6249
9	6253	6253	6253	6250	6251	6251	6251	6253	6252	6253	6253	6253	6249	6249	6249
10	6253	6252	6253	6254	6255	6253	6253	6252	6250	6251	6254	6255	6249	6249	6249
11	6253	6253	6250	6250	6252	6253	6253	6253	6251	6253	6253	6250	6249	6249	6250
12	6253	6253	6253	6255	6255	6251	6255	6254	6257	6254	6253	6250	6249	6251	6250
13	6251	6251	6253	6255	6252	6252	6255	6253	6253	6252	6253	6250	6250	6250	6250
14	6253	6252	6251	6250	6255	6252	6251	6253	6252	6251	6254	6250	6249	6250	6250
15	6253	6253	6255	6253	6254	6253	6251	6254	6252	6251	6253	6254	6249	6249	6253
16	6254	6251	6255	6251	6255	6252	6251	6253	6252	6252	6253	6254	6250	6249	6249
17	6253	6253	6253	6251	6250	6254	6250	6253	6252	6251	6254	6250	6249	6249	6249
18	6253	6253	6254	6255	6255	6251	6251	6253	6257	6255	6253	6250	6249	6250	6251
19	6253	6253	6252	6250	6253	6251	6251	6254	6252	6249	6254	6250	6249	6250	6250
20	6253	6253	6255	6250	6255	6251	6251	6254	6251	6253	6253	6251	6251	6251	6250
21	6253	6254	6254	6255	6250	6250	6251	6251	6252	6251	6254	6250	6249	6248	6250
22	6253	6254	6255	6250	6254	6252	6252	6253	6252	6256	6254	6250	6249	6249	6249
23	6253	6253	6250	6255	6254	6252	6252	6253	6252	6256	6253	6250	6250	6249	6249
25	6253	6252	6250	6250	6255	6252	6255	6253	6252	6251	6253	6254	6249	6249	6251
30	6253	6253	6253	6251	6254	6253	6252	6254	6253	6254	6253	6249	6249	6249	6250
40	6253	6254	6250	6250	6252	6253	6251	6253	6252	6253	6254	6253	6250	6249	6250

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	6251 bytes	–	100%
1,000	6249 bytes	-2 bytes	100%
10,000	6248 bytes	-1 byte	100%
100,000	6248 bytes	–	0.29%
1,000,000	6248 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)	6255 bytes	+7 bytes (+0.11%)	–
1	6255 bytes	+7 bytes (+0.11%)	–
2	6273 bytes	+25 bytes (+0.40%)	+18 bytes
3	6304 bytes	+56 bytes (+0.90%)	+49 bytes
4	6339 bytes	+91 bytes (+1.46%)	+84 bytes
5	6358 bytes	+110 bytes (+1.76%)	+103 bytes
6	6380 bytes	+132 bytes (+2.11%)	+125 bytes
7	6416 bytes	+168 bytes (+2.69%)	+161 bytes
8	6447 bytes	+199 bytes (+3.19%)	+192 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	5450 bytes	-798 bytes (-12.77%)
Brotli (Wikipedia)	brotli	brotli -q 11	5793 bytes	-455 bytes (-7.28%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5881 bytes	-367 bytes (-5.87%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	6191 bytes	-57 bytes (-0.91%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	6217 bytes	-31 bytes (-0.50%)
Zstandard (Wikipedia)	zstd	zstd -19	6253 bytes	+5 bytes (+0.08%)
LZMA2 (Wikipedia)	xz	xz -9	6284 bytes	+36 bytes (+0.58%)

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.