React 15.5.2 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 136016 bytes (132.8k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 17488 bytes (17.1k, 13%).

After GZIP compression these minified files vary in size:

gzip -6 (default)	6290 bytes (6.1k)	local copy
jsdelivr	6270 bytes (6.1k)	CDN
unpkg	6270 bytes (6.1k)	CDN
gzip -9	6267 bytes (6.1k)	local copy
7zip -mx=9 -tgzip	6118 bytes (6.0k)	local copy
zultra	6115 bytes (6.0k)	local copy
libdeflate -12	6107 bytes (6.0k)	local copy
pigz -11 -n	6107 bytes (6.0k)	local copy
kzip -s0 -rn -b4	6056 bytes (5.9k)	local copy
Zopfli	6006 bytes (5.9k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/react/react-15.5.2.min.js (or via HTTPS)

You will automatically get the smallest React 15.5.2 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 264 bytes by using my React 15.5.2 Zopfli version instead of the best available CDN (4.40% smaller than unpkg, 6006 vs. 6270 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 --i1000000 --mb8 --mls128 --bsr19 --lazy --ohh

(found April 12, 2017)

Description	Value	Parameter
iterations	1000000	--i1000000
maximum blocks	8	--mb8
maximum length score	128	--mls128
block splitting recursion	19	--bsr19
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-15.5.2.min.js --location | md5sum
e1e7feaafe35f0f9fff3ea7615666268 -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-15.5.2.min.zopfli.js.gz | md5sum
e1e7feaafe35f0f9fff3ea7615666268 -

SHA1:
curl --silent --compressed https://fb.me/react-15.5.2.min.js --location | sha1sum
d2f39ac4ded57dbc769064841557592359657faf -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-15.5.2.min.zopfli.js.gz | sha1sum
d2f39ac4ded57dbc769064841557592359657faf -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
jsdelivr	6270 bytes	e1e7feaafe35f0f9fff3ea7615666268	December 4, 2019 @ 18:03
unpkg	6270 bytes	e1e7feaafe35f0f9fff3ea7615666268	April 11, 2017 @ 14:47

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
6006 bytes	-1 byte	zopfli --i1000000 --mls128 --bsr19 --lazy --ohh	April 12, 2017 @ 12:18
6007 bytes	-1 byte	zopfli --i100000 --mls128 --bsr19 --lazy --ohh	April 11, 2017 @ 18:35
6008 bytes	-1 byte	zopfli --i10000 --mls512 --bsr25 --lazy --ohh	April 11, 2017 @ 15:28
6009 bytes	-1 byte	zopfli --i1000 --mls512 --bsr25 --lazy --ohh	April 11, 2017 @ 15:00
6010 bytes	-2 bytes	zopfli --i1000 --mls128 --bsr19 --lazy --ohh	April 11, 2017 @ 15:00
6012 bytes	–	zopfli --i100 --mls128 --bsr25 --lazy --ohh	April 11, 2017 @ 14:53

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 @ 12:53.

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	6110	6109	6109	6106	6106	6106	6106	6106	6106	6106	6106	6104	6110	6109	6109
4	6111	6111	6109	6105	6106	6106	6106	6106	6106	6106	6106	6103	6103	6105	6105
6	6108	6107	6109	6105	6109	6106	6106	6106	6106	6106	6106	6104	6103	6033	6033
7	6109	6107	6109	6109	6109	6025	6106	6106	6106	6100	6106	6028	6110	6101	6101
8	6109	6109	6109	6109	6110	6103	6106	6101	6106	6106	6106	6104	6102	6101	6101
9	6109	6108	6107	6107	6105	6106	6106	6101	6106	6106	6106	6104	6104	6071	6031
10	6102	6110	6109	6037	6106	6106	6106	6106	6106	6100	6106	6104	6103	6103	6103
11	6109	6108	6109	6105	6108	6106	6008	6106	6106	6106	6106	6022	6104	6101	6101
12	6110	6110	6102	6109	6106	6028	6106	6106	6106	6101	6106	6104	6109	6101	6101
13	6111	6109	6109	6105	6108	6025	6106	6106	6106	6106	6106	6104	6102	6104	6104
14	6111	6110	6109	6107	6106	6026	6106	6101	6106	6106	6106	6104	6104	6069	6018
15	6109	6109	6109	6109	6110	6026	6106	6106	6106	6106	6106	6104	6104	6101	6101
16	6109	6110	6109	6109	6106	6106	6106	6106	6012	6106	6106	6104	6102	6026	6026
17	6109	6109	6109	6110	6108	6024	6106	6106	6106	6106	6106	6104	6103	6101	6101
18	6104	6106	6101	6106	6106	6106	6106	6101	6106	6101	6106	6104	6109	6101	6101
19	6103	6103	6109	6107	6108	6106	6006	6106	6012	6106	6106	6104	6109	6105	6105
20	6109	6108	6031	6106	6108	6026	6106	6101	6106	6101	6106	6104	6104	6101	6101
21	6109	6108	6109	6109	6105	6106	6106	6101	6106	6101	6106	6104	6102	6101	6014
22	6110	6110	6109	6109	6109	6007	6008	6106	6011	6106	6106	6104	6110	6109	6109
23	6109	6108	6109	6109	6109	6031	6106	6106	6106	6100	6106	6026	6103	6105	6105
25	6110	6110	6109	6105	6108	6012	6006	6106	6006	6106	6106	6104	6104	6104	6104
30	6109	6109	6100	6102	6106	6105	6106	6106	6106	6101	6106	6104	6102	6104	6104
40	6103	6111	6010	6109	6109	6107	6008	6106	6106	6100	6106	6103	6104	6103	6021

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	6012 bytes	–	100%
1,000	6009 bytes	-3 bytes	100%
10,000	6008 bytes	-1 byte	100%
100,000	6007 bytes	-1 byte	2.32%
1,000,000	6006 bytes	-1 byte	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)	6102 bytes	+96 bytes (+1.60%)	+46 bytes
1	6102 bytes	+96 bytes (+1.60%)	+46 bytes
2	6101 bytes	+95 bytes (+1.58%)	+45 bytes
3	6062 bytes	+56 bytes (+0.93%)	+6 bytes
4	6056 bytes	+50 bytes (+0.83%)	–
5	6086 bytes	+80 bytes (+1.33%)	+30 bytes
6	6114 bytes	+108 bytes (+1.80%)	+58 bytes
7	6145 bytes	+139 bytes (+2.31%)	+89 bytes
8	6163 bytes	+157 bytes (+2.61%)	+107 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
Brotli (Wikipedia)	brotli	brotli -q 11	5556 bytes	-450 bytes (-7.49%)
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	5579 bytes	-427 bytes (-7.11%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5939 bytes	-67 bytes (-1.12%)
LZMA2 (Wikipedia)	xz	xz -9	5976 bytes	-30 bytes (-0.50%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	6061 bytes	+55 bytes (+0.92%)
Zstandard (Wikipedia)	zstd	zstd -19	6079 bytes	+73 bytes (+1.22%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	6239 bytes	+233 bytes (+3.88%)

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.