React 16.8.6 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 102553 bytes (100.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 12682 bytes (12.4k, 12%).

After GZIP compression these minified files vary in size:

gzip -6 (default)	4908 bytes (4.8k)	local copy
gzip -9	4903 bytes (4.8k)	local copy
cdnjs	4896 bytes (4.8k)	CDN
Boot	4888 bytes (4.8k)	CDN
jsdelivr	4888 bytes (4.8k)	CDN
zultra	4809 bytes (4.7k)	local copy
7zip -mx=9 -tgzip	4808 bytes (4.7k)	local copy
libdeflate -12	4808 bytes (4.7k)	local copy
pigz -11 -n	4808 bytes (4.7k)	local copy
kzip -s0 -rn -b1	4805 bytes (4.7k)	local copy
Zopfli	4800 bytes (4.7k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/react/react-16.8.6.min.js (or via HTTPS)

You will automatically get the smallest React 16.8.6 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 88 bytes by using my React 16.8.6 Zopfli version instead of the best available CDN (1.83% smaller than jsdelivr, 4800 vs. 4888 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 --mls32 --bsr30 --lazy --ohh

(found August 7, 2019)

Description	Value	Parameter
iterations	10000	--i10000
maximum blocks	8	--mb8
maximum length score	32	--mls32
block splitting recursion	30	--bsr30
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-16.8.6.min.js --location | md5sum
f808b8e8ab51b0d9525795db3768cd86 -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-16.8.6.min.zopfli.js.gz | md5sum
f808b8e8ab51b0d9525795db3768cd86 -

SHA1:
curl --silent --compressed https://fb.me/react-16.8.6.min.js --location | sha1sum
da282c1a379fe3b12bc064159bdf5cb3c7b70d13 -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-16.8.6.min.zopfli.js.gz | sha1sum
da282c1a379fe3b12bc064159bdf5cb3c7b70d13 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
cdnjs	4896 bytes	f808b8e8ab51b0d9525795db3768cd86	March 28, 2019 @ 08:00
Boot	4888 bytes	f808b8e8ab51b0d9525795db3768cd86	March 28, 2019 @ 08:00
jsdelivr	4888 bytes	f808b8e8ab51b0d9525795db3768cd86	August 7, 2019 @ 16:21

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
4800 bytes	-1 byte	zopfli --i10000 --mls32 --bsr30 --lazy --ohh	August 7, 2019 @ 17:16
4801 bytes	-1 byte	zopfli --i1000 --mls32 --bsr30 --lazy --ohh	August 7, 2019 @ 17:09
4802 bytes	–	zopfli --i100 --mls32 --bsr30 --lazy --ohh	August 7, 2019 @ 16:29

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 @ 12:51.

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	4805	4805	4805	4812	4808	4805	4809	4808	4805	4805	4805	4804	4804	4804	4804
4	4805	4805	4805	4805	4805	4805	4805	4809	4805	4805	4805	4805	4810	4807	4807
6	4805	4805	4805	4805	4807	4805	4807	4810	4805	4805	4805	4805	4810	4803	4803
7	4805	4805	4805	4805	4802	4805	4806	4808	4805	4805	4805	4803	4803	4803	4803
8	4808	4808	4805	4808	4807	4808	4808	4807	4805	4805	4805	4804	4804	4804	4804
9	4805	4805	4805	4806	4806	4805	4808	4806	4805	4805	4805	4803	4809	4812	4812
10	4809	4809	4808	4807	4807	4808	4808	4808	4805	4805	4805	4804	4808	4808	4808
11	4805	4805	4805	4805	4807	4805	4807	4808	4805	4805	4805	4803	4803	4803	4803
12	4807	4807	4808	4807	4806	4805	4808	4810	4805	4805	4804	4806	4810	4810	4810
13	4805	4805	4808	4807	4807	4808	4808	4806	4805	4805	4805	4804	4803	4804	4804
14	4807	4807	4808	4806	4807	4808	4807	4808	4805	4805	4804	4803	4808	4809	4809
15	4808	4808	4808	4807	4807	4808	4808	4807	4805	4805	4805	4804	4803	4803	4803
16	4808	4808	4808	4807	4806	4808	4808	4807	4805	4805	4805	4803	4803	4810	4810
17	4805	4805	4805	4808	4807	4808	4808	4808	4805	4805	4805	4803	4803	4804	4804
18	4807	4807	4807	4808	4807	4808	4808	4808	4805	4805	4805	4804	4804	4804	4804
19	4805	4805	4807	4808	4807	4808	4808	4808	4805	4805	4805	4803	4810	4811	4811
20	4807	4807	4808	4809	4807	4809	4808	4808	4805	4805	4805	4803	4803	4803	4803
21	4805	4805	4808	4807	4807	4808	4807	4808	4805	4805	4805	4803	4803	4803	4803
22	4808	4808	4808	4808	4806	4808	4808	4806	4805	4805	4805	4803	4803	4803	4803
23	4807	4807	4808	4807	4807	4805	4807	4808	4805	4805	4804	4804	4810	4803	4803
25	4809	4809	4807	4807	4808	4809	4809	4807	4805	4805	4805	4804	4810	4810	4810
30	4805	4805	4809	4807	4800	4800	4808	4808	4805	4805	4805	4804	4803	4803	4803
40	4807	4807	4807	4807	4807	4809	4807	4807	4805	4805	4805	4803	4803	4803	4803

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	4802 bytes	–	100%
1,000	4801 bytes	-1 byte	100%
10,000	4800 bytes	-1 byte	100%
100,000	4800 bytes	–	1.74%
1,000,000	4800 bytes	–	0.58%
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)	4807 bytes	+7 bytes (+0.15%)	+2 bytes
1	4805 bytes	+5 bytes (+0.10%)	–
2	4818 bytes	+18 bytes (+0.38%)	+13 bytes
3	4846 bytes	+46 bytes (+0.96%)	+41 bytes
4	4870 bytes	+70 bytes (+1.46%)	+65 bytes
5	4905 bytes	+105 bytes (+2.19%)	+100 bytes
6	4934 bytes	+134 bytes (+2.79%)	+129 bytes
7	4965 bytes	+165 bytes (+3.44%)	+160 bytes
8	4987 bytes	+187 bytes (+3.90%)	+182 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	4318 bytes	-482 bytes (-10.04%)
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	4401 bytes	-399 bytes (-8.31%)
Zstandard (Wikipedia)	zstd	zstd -19	4789 bytes	-11 bytes (-0.23%)
LZMA2 (Wikipedia)	xz	xz -9	4836 bytes	+36 bytes (+0.75%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	4934 bytes	+134 bytes (+2.79%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	4955 bytes	+155 bytes (+3.23%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	5166 bytes	+366 bytes (+7.63%)

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 2025.
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.