React 15.6.2 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 141859 bytes (138.5k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 22918 bytes (22.4k, 16%).

After GZIP compression these minified files vary in size:

gzip -6 (default)	7905 bytes (7.7k)	local copy
unpkg	7891 bytes (7.7k)	CDN
jsdelivr	7885 bytes (7.7k)	CDN
gzip -9	7882 bytes (7.7k)	local copy
zultra	7696 bytes (7.5k)	local copy
7zip -mx=9 -tgzip	7694 bytes (7.5k)	local copy
libdeflate -12	7691 bytes (7.5k)	local copy
kzip -s0 -rn -b6	7684 bytes (7.5k)	local copy
pigz -11 -n	7585 bytes (7.4k)	local copy
Zopfli	7572 bytes (7.4k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/react/react-15.6.2.min.js (or via HTTPS)

You will automatically get the smallest React 15.6.2 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 313 bytes by using my React 15.6.2 Zopfli version instead of the best available CDN (4.13% smaller than jsdelivr, 7572 vs. 7885 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 --mls32 --bsr25 --lazy --ohh

(found September 27, 2017)

Description	Value	Parameter
iterations	100000	--i100000
maximum blocks	8	--mb8
maximum length score	32	--mls32
block splitting recursion	25	--bsr25
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://fb.me/react-15.6.2.min.js --location | md5sum
182301dc5d717c4f828b5665ac6bfa3a -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-15.6.2.min.zopfli.js.gz | md5sum
182301dc5d717c4f828b5665ac6bfa3a -

SHA1:
curl --silent --compressed https://fb.me/react-15.6.2.min.js --location | sha1sum
3fcf6121e7f647b59e314ec92d23e093a4c3b303 -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-15.6.2.min.zopfli.js.gz | sha1sum
3fcf6121e7f647b59e314ec92d23e093a4c3b303 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
unpkg	7891 bytes	182301dc5d717c4f828b5665ac6bfa3a	September 26, 2017 @ 02:09
jsdelivr	7885 bytes	182301dc5d717c4f828b5665ac6bfa3a	December 4, 2019 @ 18:03

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

Available React versions at minime.stephan-brumme.com:

18.2.0,
18.1.0, 18.0.0,
17.0.2, 17.0.1, 17.0.0,
16.14.0,
16.13.1, 16.13.0,
16.12.0,
16.11.0,
16.10.2, 16.10.1, 16.10.0,
16.9.0,
16.8.6, 16.8.5, 16.8.4, 16.8.3, 16.8.2, 16.8.1, 16.8.0,
16.7.0,
16.6.3, 16.6.1, 16.6.0,
16.5.2, 16.5.1, 16.5.0,
16.4.2, 16.4.1, 16.4.0,
16.3.2, 16.3.1, 16.3.0,
16.2.0,
16.1.1, 16.1.0, 16.0.0,
15.6.2, 15.6.1, 15.6.0,
15.5.2, 15.5.1, 15.5.0,
15.4.2, 15.4.1, 15.4.0,
15.3.2, 15.3.1, 15.3.0,
15.2.1, 15.2.0,
15.1.0,
15.0.2, 15.0.1, 15.0.0,
0.14.8, 0.14.7, 0.14.6, 0.14.5, 0.14.4, 0.14.3, 0.14.2, 0.14.1, 0.14.0,
0.13.3, 0.13.2, 0.13.1, 0.13.0,
0.12.2, 0.12.1, 0.12.0,
0.11.2, 0.11.1, 0.11.0,
0.10.0

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Dojo, Ember, jQuery, Knockout, lodash, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:

Size	Improvement	Parameters	Found
7572 bytes	-1 byte	zopfli --i100000 --mls32 --bsr25 --lazy --ohh	September 27, 2017 @ 16:15
7573 bytes	-1 byte	zopfli --i100000 --mls32 --bsr20 --lazy --ohh	September 27, 2017 @ 15:58
7574 bytes	-1 byte	zopfli --i10000 --mls32 --bsr20 --lazy --ohh	September 27, 2017 @ 15:06
7575 bytes	-2 bytes	zopfli --i1000 --mls128 --bsr20 --lazy --ohh	September 27, 2017 @ 14:39
7577 bytes	–	zopfli --i100 --mls512 --bsr15 --lazy --ohh	September 27, 2017 @ 14:03

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, 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	7599	7600	7624	7594	7591	7593	7593	7592	7593	7596	7685	7613	7626	7622	7622
4	7593	7590	7584	7583	7581	7584	7581	7582	7583	7578	7577	7587	7588	7600	7573
6	7587	7587	7581	7580	7575	7576	7576	7573	7573	7576	7573	7575	7578	7579	7573
7	7580	7580	7575	7580	7575	7582	7574	7583	7584	7580	7576	7578	7578	7580	7580
8	7580	7580	7578	7580	7572	7576	7576	7576	7576	7582	7575	7577	7577	7579	7575
9	7590	7590	7585	7586	7578	7578	7573	7582	7577	7576	7579	7575	7575	7579	7578
10	7587	7587	7578	7580	7575	7578	7575	7575	7576	7576	7573	7578	7578	7580	7580
11	7583	7583	7578	7582	7575	7576	7576	7578	7573	7578	7582	7576	7574	7580	7581
12	7581	7580	7573	7580	7573	7576	7576	7577	7576	7578	7575	7576	7576	7579	7576
13	7580	7580	7578	7580	7572	7576	7576	7573	7573	7578	7578	7578	7576	7580	7576
14	7586	7586	7578	7580	7573	7578	7574	7576	7576	7580	7575	7577	7578	7579	7575
15	7582	7582	7579	7583	7573	7577	7577	7576	7573	7576	7575	7578	7576	7579	7575
16	7583	7583	7578	7581	7576	7576	7576	7576	7573	7576	7575	7578	7578	7579	7575
17	7580	7580	7580	7581	7573	7576	7576	7575	7576	7576	7573	7578	7578	7580	7575
18	7585	7585	7578	7580	7573	7576	7576	7576	7573	7576	7575	7578	7578	7579	7578
19	7582	7582	7578	7581	7573	7578	7576	7575	7577	7577	7573	7578	7579	7580	7580
20	7580	7580	7580	7582	7573	7578	7573	7575	7573	7578	7575	7578	7573	7580	7580
21	7580	7580	7576	7577	7576	7579	7578	7573	7577	7577	7575	7575	7576	7579	7579
22	7582	7582	7580	7578	7572	7577	7576	7576	7575	7579	7576	7576	7578	7577	7578
23	7578	7578	7577	7573	7576	7577	7582	7575	7576	7578	7604	7576	7577	7577	7578
25	7582	7582	7575	7578	7572	7577	7576	7575	7573	7605	7601	7578	7576	7578	7580
30	7583	7582	7579	7582	7573	7576	7577	7576	7577	7576	7573	7576	7573	7579	7576
40	7580	7580	7579	7582	7573	7576	7577	7576	7577	7580	7577	7576	7577	7580	7577

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	7577 bytes	–	100%
1,000	7575 bytes	-2 bytes	100%
10,000	7574 bytes	-1 byte	100%
100,000	7572 bytes	-2 bytes	11.59%
1,000,000	7572 bytes	–	1.16%
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)	7689 bytes	+117 bytes (+1.55%)	+5 bytes
1	7689 bytes	+117 bytes (+1.55%)	+5 bytes
2	7690 bytes	+118 bytes (+1.56%)	+6 bytes
3	7723 bytes	+151 bytes (+1.99%)	+39 bytes
4	7747 bytes	+175 bytes (+2.31%)	+63 bytes
5	7754 bytes	+182 bytes (+2.40%)	+70 bytes
6	7684 bytes	+112 bytes (+1.48%)	–
7	7721 bytes	+149 bytes (+1.97%)	+37 bytes
8	7760 bytes	+188 bytes (+2.48%)	+76 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	6932 bytes	-640 bytes (-8.45%)
Brotli (Wikipedia)	brotli	brotli -q 11	6949 bytes	-623 bytes (-8.23%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	7369 bytes	-203 bytes (-2.68%)
LZMA2 (Wikipedia)	xz	xz -9	7504 bytes	-68 bytes (-0.90%)
Zstandard (Wikipedia)	zstd	zstd -19	7634 bytes	+62 bytes (+0.82%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	7647 bytes	+75 bytes (+0.99%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	7802 bytes	+230 bytes (+3.04%)

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 2024.
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.