BackboneJS 1.4.1 (latest) - as small as it gets (near-perfect GZIP compression)

The original file has 78181 bytes (76.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 25200 bytes (24.6k, 32%).

After GZIP compression these minified files vary in size:

unpkg	10200 bytes (10.0k)	CDN
jsdelivr	8188 bytes (8.0k)	CDN
gzip -6 (default)	8044 bytes (7.9k)	local copy
gzip -9	8032 bytes (7.8k)	local copy
Boot	8029 bytes (7.8k)	CDN
cdnjs	8020 bytes (7.8k)	CDN
zultra	7793 bytes (7.6k)	local copy
libdeflate -12	7784 bytes (7.6k)	local copy
7zip -mx=9 -tgzip	7783 bytes (7.6k)	local copy
pigz -11 -n	7783 bytes (7.6k)	local copy
kzip -s0 -rn -b0	7781 bytes (7.6k)	local copy
Zopfli	7776 bytes (7.6k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-1.4.1.min.js (or via HTTPS)

You will automatically get the smallest BackboneJS 1.4.1 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 244 bytes by using my BackboneJS 1.4.1 Zopfli version instead of the best available CDN (3.14% smaller than cdnjs, 7776 vs. 8020 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 --mls512 --bsr20 --lazy --ohh

(found March 21, 2022)

Description	Value	Parameter
iterations	100000	--i100000
maximum blocks	8	--mb8
maximum length score	512	--mls512
block splitting recursion	20	--bsr20
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/1.4.1/backbone-min.js --location | md5sum
9b0a6dd82088805382155bd283301fe7 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-1.4.1.min.zopfli.js.gz | md5sum
9b0a6dd82088805382155bd283301fe7 -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/1.4.1/backbone-min.js --location | sha1sum
349da661de6c8a36e7e61c31df2516bf80321394 -
curl --silent --compressed https://minime.stephan-brumme.com/files/backbonejs/backbone-1.4.1.min.zopfli.js.gz | sha1sum
349da661de6c8a36e7e61c31df2516bf80321394 -

These CDNs send you the original file:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
unpkg	10200 bytes	9b0a6dd82088805382155bd283301fe7	(invalid)
Boot	8029 bytes	9b0a6dd82088805382155bd283301fe7	March 21, 2022 @ 10:36
cdnjs	8020 bytes	9b0a6dd82088805382155bd283301fe7	(invalid)

And some CDNs send you a different file:

CDN	Size (compressed)	MD5 (uncompressed)	Comment / Diff	Timestamp
jsdelivr	8188 bytes	43e2d4b0e82170cc55e5343bf3ef813b	< (function(r){var n=typeof self=="object"&&self.self===self [...] < //# sourceMappingURL=backbone-min.js.map > /** > * Minified by jsDelivr using Terser v5.10.0. > * Original file: /npm/backbone@1.4.1/backbone.js > * > * Do NOT use SRI with dynamically generated files! More i [...] > */ > !function(t){var e="object"==typeof self&&self.self===self [...] > //# sourceMappingURL=/sm/257d7ea98c6e5fed07b55c249c3eb275e [...]	March 21, 2022 @ 10:36

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
7776 bytes	-1 byte	zopfli --i100000 --mls512 --bsr20 --lazy --ohh	March 21, 2022 @ 11:16
7777 bytes	-1 byte	zopfli --i10000 --mls512 --bsr20 --lazy --ohh	March 21, 2022 @ 10:47
7778 bytes	-1 byte	zopfli --i1000 --mls512 --bsr20 --lazy --ohh	March 21, 2022 @ 10:45
7779 bytes	–	zopfli --i100 --mls2048 --bsr14 --lazy --ohh	March 21, 2022 @ 10:36

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on March 22, 2022 @ 09:01.

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	7784	7784	7785	7784	7785	7784	7784	7785	7784	7784	7784	7779	7780	7780	7780
4	7779	7780	7780	7779	7780	7781	7778	7779	7778	7778	7778	7783	7780	7779	7779
6	7779	7781	7779	7780	7780	7780	7780	7780	7780	7779	7780	7780	7779	7778	7776
7	7779	7781	7779	7779	7780	7780	7778	7780	7780	7779	7778	7779	7778	7779	7780
8	7779	7780	7780	7779	7780	7780	7778	7779	7780	7779	7778	7780	7779	7778	7778
9	7780	7780	7779	7780	7779	7780	7778	7779	7779	7778	7780	7780	7778	7778	7778
10	7780	7780	7780	7780	7781	7781	7777	7779	7779	7779	7778	7779	7779	7776	7777
11	7780	7781	7780	7779	7780	7780	7780	7779	7776	7777	7780	7780	7780	7779	7776
12	7779	7781	7780	7779	7780	7778	7779	7779	7780	7776	7778	7780	7780	7778	7779
13	7781	7781	7780	7780	7780	7778	7779	7779	7780	7779	7780	7780	7778	7778	7778
14	7780	7780	7780	7779	7780	7779	7779	7779	7780	7780	7778	7780	7779	7778	7778
15	7779	7780	7780	7779	7780	7779	7779	7779	7778	7777	7778	7780	7778	7782	7778
16	7780	7779	7779	7779	7780	7780	7780	7779	7780	7779	7781	7781	7778	7779	7776
17	7779	7780	7780	7779	7780	7779	7780	7779	7779	7779	7780	7780	7779	7779	7778
18	7780	7780	7780	7779	7780	7780	7779	7779	7779	7777	7778	7780	7779	7778	7778
19	7781	7780	7780	7780	7779	7780	7780	7780	7780	7779	7780	7780	7778	7778	7778
20	7781	7779	7781	7780	7780	7780	7778	7779	7776	7776	7778	7780	7778	7776	7776
21	7780	7780	7780	7779	7780	7780	7780	7779	7780	7779	7780	7780	7779	7778	7776
22	7779	7779	7780	7780	7780	7780	7779	7779	7780	7779	7778	7780	7778	7778	7776
23	7781	7781	7779	7779	7780	7780	7778	7779	7780	7779	7780	7780	7779	7778	7777
25	7779	7781	7780	7780	7780	7780	7779	7779	7779	7777	7778	7780	7779	7778	7776
30	7781	7779	7779	7781	7781	7780	7779	7779	7779	7778	7781	7780	7779	7779	7778
40	7779	7781	7780	7780	7780	7781	7778	7779	7779	7779	7778	7779	7779	7776	7776

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	7779 bytes	–	100%
1,000	7778 bytes	-1 byte	100%
10,000	7777 bytes	-1 byte	100%
100,000	7776 bytes	-1 byte	6.38%
1,000,000	7776 bytes	–	4.35%
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)	7781 bytes	+5 bytes (+0.06%)	–
1	7781 bytes	+5 bytes (+0.06%)	–
2	7805 bytes	+29 bytes (+0.37%)	+24 bytes
3	7832 bytes	+56 bytes (+0.72%)	+51 bytes
4	7862 bytes	+86 bytes (+1.11%)	+81 bytes
5	7890 bytes	+114 bytes (+1.47%)	+109 bytes
6	7901 bytes	+125 bytes (+1.61%)	+120 bytes
7	7942 bytes	+166 bytes (+2.13%)	+161 bytes
8	7971 bytes	+195 bytes (+2.51%)	+190 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	6733 bytes	-1043 bytes (-13.41%)
Brotli (Wikipedia)	brotli	brotli -q 11	7259 bytes	-517 bytes (-6.65%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	7335 bytes	-441 bytes (-5.67%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	7338 bytes	-438 bytes (-5.63%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	7645 bytes	-131 bytes (-1.68%)
Zstandard (Wikipedia)	zstd	zstd -19	7740 bytes	-36 bytes (-0.46%)
LZMA2 (Wikipedia)	xz	xz -9	7772 bytes	-4 bytes (-0.05%)

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.