React 16.10.1 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 120826 bytes (118.0k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 12703 bytes (12.4k, 11%).

After GZIP compression these minified files vary in size:

gzip -6 (default)	5018 bytes (4.9k)	local copy
gzip -9	5018 bytes (4.9k)	local copy
Boot	5002 bytes (4.9k)	CDN
cdnjs	5002 bytes (4.9k)	CDN
jsdelivr	4997 bytes (4.9k)	CDN
zultra	4921 bytes (4.8k)	local copy
libdeflate -12	4919 bytes (4.8k)	local copy
kzip -s0 -rn -b0	4917 bytes (4.8k)	local copy
pigz -11 -n	4917 bytes (4.8k)	local copy
7zip -mx=9 -tgzip	4915 bytes (4.8k)	local copy
Zopfli	4907 bytes (4.8k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/react/react-16.10.1.min.js (or via HTTPS)

You will automatically get the smallest React 16.10.1 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 90 bytes by using my React 16.10.1 Zopfli version instead of the best available CDN (1.83% smaller than jsdelivr, 4907 vs. 4997 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 --mls32768 --bsr2 --lazy --ohh

(found October 4, 2019)

Description	Value	Parameter
iterations	1000000	--i1000000
maximum blocks	8	--mb8
maximum length score	32768	--mls32768
block splitting recursion	2	--bsr2
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-16.10.1.min.js --location | md5sum
868c805083f69ecc8fc3185b2c63cefa -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-16.10.1.min.zopfli.js.gz | md5sum
868c805083f69ecc8fc3185b2c63cefa -

SHA1:
curl --silent --compressed https://fb.me/react-16.10.1.min.js --location | sha1sum
fc55edb4a2d1f54b77e7c805ea2d19e09627a66b -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-16.10.1.min.zopfli.js.gz | sha1sum
fc55edb4a2d1f54b77e7c805ea2d19e09627a66b -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	5002 bytes	868c805083f69ecc8fc3185b2c63cefa	September 28, 2019 @ 21:16
cdnjs	5002 bytes	868c805083f69ecc8fc3185b2c63cefa	September 28, 2019 @ 21:16
jsdelivr	4997 bytes	868c805083f69ecc8fc3185b2c63cefa	October 4, 2019 @ 13:00

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
4907 bytes	-2 bytes	zopfli --i1000000 --mls32768 --bsr2 --lazy --ohh	October 4, 2019 @ 18:46
4909 bytes	-1 byte	zopfli --i100000 --mls32768 --bsr2 --lazy --ohh	October 4, 2019 @ 17:07
4910 bytes	-2 bytes	zopfli --i10000 --mls16384 --bsr2 --lazy --ohh	October 4, 2019 @ 13:58
4912 bytes	-1 byte	zopfli --i1000 --mls8 --bsr17 --lazy --ohh	October 4, 2019 @ 13:43
4913 bytes	–	zopfli --i100 --mls256 --bsr10 --lazy --ohh	October 4, 2019 @ 13:05

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	4915	4915	4913	4915	4915	4915	4914	4913	4913	4913	4913	4913	4908	4907	4907
4	4912	4912	4916	4915	4913	4913	4913	4913	4913	4913	4913	4912	4913	4914	4914
6	4914	4914	4913	4915	4913	4914	4912	4914	4913	4913	4913	4916	4914	4913	4913
7	4914	4914	4914	4915	4913	4912	4912	4912	4913	4913	4913	4913	4913	4913	4913
8	4914	4914	4911	4915	4913	4915	4912	4913	4913	4913	4913	4916	4914	4913	4913
9	4915	4915	4914	4913	4914	4912	4912	4913	4913	4913	4913	4912	4914	4914	4914
10	4915	4915	4914	4914	4913	4911	4912	4912	4913	4913	4913	4916	4915	4914	4914
11	4917	4917	4915	4913	4914	4912	4912	4912	4913	4913	4913	4916	4914	4913	4913
12	4914	4914	4914	4914	4914	4911	4912	4914	4913	4913	4913	4913	4915	4914	4914
13	4912	4912	4912	4914	4914	4911	4913	4914	4913	4913	4913	4916	4914	4915	4915
14	4915	4915	4913	4914	4914	4912	4913	4912	4913	4913	4913	4914	4913	4913	4913
15	4914	4914	4914	4915	4913	4912	4912	4913	4913	4913	4913	4916	4914	4911	4911
16	4915	4915	4912	4914	4912	4913	4913	4914	4913	4913	4913	4916	4913	4913	4913
17	4913	4913	4912	4914	4913	4911	4912	4914	4913	4913	4913	4916	4914	4914	4914
18	4914	4914	4913	4914	4913	4912	4912	4913	4913	4913	4913	4916	4914	4914	4914
19	4913	4913	4913	4915	4913	4911	4912	4914	4913	4913	4913	4913	4914	4914	4914
20	4912	4912	4913	4914	4913	4911	4912	4914	4913	4913	4913	4916	4915	4913	4913
21	4915	4915	4914	4914	4914	4912	4912	4913	4913	4913	4913	4914	4914	4914	4914
22	4912	4912	4915	4913	4913	4912	4912	4912	4913	4913	4913	4913	4914	4913	4913
23	4914	4914	4914	4913	4914	4913	4912	4914	4913	4913	4913	4916	4914	4914	4914
25	4915	4915	4914	4913	4913	4911	4912	4914	4913	4913	4913	4916	4915	4913	4913
30	4913	4913	4912	4915	4914	4911	4912	4914	4913	4913	4913	4915	4914	4914	4914
40	4912	4912	4911	4913	4913	4912	4912	4912	4913	4913	4913	4914	4914	4914	4914

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	4913 bytes	–	100%
1,000	4912 bytes	-1 byte	100%
10,000	4910 bytes	-2 bytes	100%
100,000	4909 bytes	-1 byte	0.87%
1,000,000	4907 bytes	-2 bytes	0.87%
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)	4917 bytes	+10 bytes (+0.20%)	–
1	4918 bytes	+11 bytes (+0.22%)	+1 byte
2	4932 bytes	+25 bytes (+0.51%)	+15 bytes
3	4954 bytes	+47 bytes (+0.96%)	+37 bytes
4	4965 bytes	+58 bytes (+1.18%)	+48 bytes
5	4994 bytes	+87 bytes (+1.77%)	+77 bytes
6	5027 bytes	+120 bytes (+2.45%)	+110 bytes
7	5057 bytes	+150 bytes (+3.06%)	+140 bytes
8	5099 bytes	+192 bytes (+3.91%)	+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	4419 bytes	-488 bytes (-9.94%)
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	4501 bytes	-406 bytes (-8.27%)
Zstandard (Wikipedia)	zstd	zstd -19	4909 bytes	+2 bytes (+0.04%)
LZMA2 (Wikipedia)	xz	xz -9	4940 bytes	+33 bytes (+0.67%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5005 bytes	+98 bytes (+2.00%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	5034 bytes	+127 bytes (+2.59%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	5257 bytes	+350 bytes (+7.13%)

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.