BackboneJS 0.9.0 - as small as it gets (near-perfect GZIP compression)

The original file has 47945 bytes (46.8k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 15552 bytes (15.2k, 32%).

After GZIP compression these minified files vary in size:

jsdelivr	6673 bytes (6.5k)	CDN
Boot	6153 bytes (6.0k)	CDN
Baidu	5474 bytes (5.3k)	CDN
cdnjs	5450 bytes (5.3k)	CDN
gzip -6 (default)	5443 bytes (5.3k)	local copy
gzip -9	5443 bytes (5.3k)	local copy
unpkg	5432 bytes (5.3k)	CDN
7zip -mx=9 -tgzip	5305 bytes (5.2k)	local copy
libdeflate -12	5303 bytes (5.2k)	local copy
zultra	5301 bytes (5.2k)	local copy
kzip -s0 -rn -b0	5295 bytes (5.2k)	local copy
pigz -11 -n	5290 bytes (5.2k)	local copy
Zopfli	5286 bytes (5.2k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-0.9.0.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 0.9.0 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 146 bytes by using my BackboneJS 0.9.0 Zopfli version instead of the best available CDN (2.76% smaller than unpkg, 5286 vs. 5432 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 --mls4096 --bsr21 --lazy --ohh

(found September 23, 2015)

Description	Value	Parameter
iterations	1000	--i1000
maximum blocks	8	--mb8
maximum length score	4096	--mls4096
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/0.9.0/backbone-min.js --location | md5sum
beeb0726f296ebf8435bdeff40151ec9 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.9.0.min.zopfli.js.gz | md5sum
beeb0726f296ebf8435bdeff40151ec9 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/0.9.0/backbone-min.js --location | sha1sum
aeb06cc84ad1c7c2fd54afd936376af3c9e4bcba -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-0.9.0.min.zopfli.js.gz | sha1sum
aeb06cc84ad1c7c2fd54afd936376af3c9e4bcba -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	6153 bytes	beeb0726f296ebf8435bdeff40151ec9	(invalid)
cdnjs	5450 bytes	beeb0726f296ebf8435bdeff40151ec9	(invalid)
unpkg	5432 bytes	beeb0726f296ebf8435bdeff40151ec9	July 11, 2016 @ 16:18

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
jsdelivr	6673 bytes	b4825a643cf8a5ebdf968ce26f7b5288	< // Backbone.js 0.9.0 > // Backbone.js 0.9.9 > < (function(){var i=this,r=i.Backbone,s=Array.prototype.slic [...] < d.next={});f.callback=b;f.context=c;d.tail=f.next={}}retur [...] < a.push({next:c.next,tail:c.tail});for(e=s.call(arguments,1 [...] < this._changed={};this._previousAttributes=f.clone(this.att [...] < e;f.isObject(a)\|\|a==null?(d=a,c=b):(d={},d[a]=b);c\|\|(c={}) [...] < f.has(b,e)!=f.has(n,e))this._changed[e]=a;if(!u)!c.silent& [...] < save:function(a,b,c){var d;f.isObject(a)\|\|a==null?(d=a,c=b [...] [...]	(invalid)
Baidu	5474 bytes	2b3165119f34b5c1a1a583938ee2fbbd	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
5286 bytes	-1 byte	zopfli --i1000 --mls4096 --bsr21 --lazy --ohh	September 23, 2015 @ 13:48
5287 bytes	–	zopfli --i100 --mls2048 --bsr13 --lazy --ohh	September 8, 2015 @ 11:33

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 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	5287	5287	5288	5287	5295	5295	5289	5289	5289	5295	5287	5290	5291	5292	5292
4	5294	5294	5294	5295	5287	5295	5295	5295	5295	5295	5287	5287	5292	5290	5290
6	5287	5287	5289	5288	5287	5287	5287	5289	5288	5287	5287	5287	5287	5287	5287
7	5289	5289	5287	5289	5288	5287	5295	5288	5288	5288	5287	5287	5287	5287	5287
8	5287	5287	5288	5287	5295	5295	5289	5289	5289	5295	5287	5287	5290	5289	5289
9	5295	5295	5288	5287	5287	5287	5287	5287	5287	5287	5287	5287	5287	5288	5288
10	5295	5295	5294	5287	5287	5287	5287	5290	5288	5287	5287	5287	5287	5287	5287
11	5287	5287	5287	5287	5287	5287	5287	5287	5287	5287	5287	5287	5287	5288	5288
12	5291	5291	5287	5287	5287	5287	5287	5287	5288	5287	5287	5290	5287	5289	5289
13	5287	5287	5287	5287	5288	5295	5287	5290	5289	5295	5287	5288	5288	5287	5287
14	5287	5287	5287	5287	5288	5287	5287	5287	5288	5287	5287	5288	5287	5287	5287
15	5295	5295	5287	5287	5287	5287	5295	5287	5288	5287	5295	5287	5288	5288	5288
16	5295	5295	5293	5288	5287	5295	5295	5295	5287	5287	5287	5287	5287	5288	5288
17	5287	5287	5288	5287	5287	5287	5287	5287	5288	5287	5287	5287	5287	5287	5287
18	5287	5287	5288	5287	5287	5287	5287	5287	5287	5287	5287	5287	5287	5288	5288
19	5295	5295	5292	5287	5287	5287	5287	5287	5288	5287	5287	5294	5287	5287	5287
20	5295	5295	5292	5294	5287	5287	5295	5288	5288	5295	5295	5287	5289	5287	5287
21	5295	5295	5287	5287	5288	5288	5287	5287	5291	5287	5287	5286	5287	5287	5287
22	5289	5289	5287	5287	5288	5287	5287	5287	5288	5287	5287	5287	5287	5287	5287
23	5291	5291	5287	5295	5288	5287	5287	5287	5288	5287	5287	5287	5287	5291	5291
25	5295	5295	5293	5295	5287	5287	5287	5287	5288	5288	5287	5287	5288	5288	5288
30	5287	5287	5287	5292	5287	5287	5287	5287	5288	5287	5287	5287	5288	5289	5289
40	5287	5287	5287	5287	5288	5287	5287	5287	5288	5287	5287	5287	5288	5288	5288

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	5287 bytes	–	100%
1,000	5286 bytes	-1 byte	100%
10,000	5286 bytes	–	100%
100,000	5286 bytes	–	0.29%
1,000,000	5286 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)	5295 bytes	+9 bytes (+0.17%)	–
1	5295 bytes	+9 bytes (+0.17%)	–
2	5326 bytes	+40 bytes (+0.76%)	+31 bytes
3	5352 bytes	+66 bytes (+1.25%)	+57 bytes
4	5368 bytes	+82 bytes (+1.55%)	+73 bytes
5	5412 bytes	+126 bytes (+2.38%)	+117 bytes
6	5451 bytes	+165 bytes (+3.12%)	+156 bytes
7	5481 bytes	+195 bytes (+3.69%)	+186 bytes
8	5516 bytes	+230 bytes (+4.35%)	+221 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	4688 bytes	-598 bytes (-11.31%)
Brotli (Wikipedia)	brotli	brotli -q 11	4827 bytes	-459 bytes (-8.68%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5316 bytes	+30 bytes (+0.57%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	5318 bytes	+32 bytes (+0.61%)
Zstandard (Wikipedia)	zstd	zstd -19	5323 bytes	+37 bytes (+0.70%)
LZMA2 (Wikipedia)	xz	xz -9	5384 bytes	+98 bytes (+1.85%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	5528 bytes	+242 bytes (+4.58%)

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.