React 16.10.0 - 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	4922 bytes (4.8k)	local copy
libdeflate -12	4919 bytes (4.8k)	local copy
kzip -s0 -rn -b1	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	4908 bytes (4.8k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/react/react-16.10.0.min.js (or via HTTPS)

You will automatically get the smallest React 16.10.0 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 89 bytes by using my React 16.10.0 Zopfli version instead of the best available CDN (1.81% smaller than jsdelivr, 4908 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 --i100000 --mb8 --mls32 --bsr18 --lazy --ohh

(found October 4, 2019)

Description	Value	Parameter
iterations	100000	--i100000
maximum blocks	8	--mb8
maximum length score	32	--mls32
block splitting recursion	18	--bsr18
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-16.10.0.min.js --location | md5sum
25fc3d28866609505498f34ea017ad0e -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-16.10.0.min.zopfli.js.gz | md5sum
25fc3d28866609505498f34ea017ad0e -

SHA1:
curl --silent --compressed https://fb.me/react-16.10.0.min.js --location | sha1sum
87119825e2f5d0a578cfbe59f1c5e8710bffed4c -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-16.10.0.min.zopfli.js.gz | sha1sum
87119825e2f5d0a578cfbe59f1c5e8710bffed4c -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	5002 bytes	25fc3d28866609505498f34ea017ad0e	September 27, 2019 @ 22:46
cdnjs	5002 bytes	25fc3d28866609505498f34ea017ad0e	September 27, 2019 @ 22:46
jsdelivr	4997 bytes	25fc3d28866609505498f34ea017ad0e	October 4, 2019 @ 12:59

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
4908 bytes	-1 byte	zopfli --i100000 --mls32 --bsr18 --lazy --ohh	October 4, 2019 @ 17:07
4909 bytes	-1 byte	zopfli --i10000 --mls32 --bsr18 --lazy --ohh	October 4, 2019 @ 14:07
4910 bytes	-2 bytes	zopfli --i10000 --mls8192 --bsr2 --lazy --ohh	October 4, 2019 @ 13:59
4912 bytes	-1 byte	zopfli --i1000 --mls32 --bsr30 --lazy --ohh	October 4, 2019 @ 13:42
4913 bytes	–	zopfli --i100 --mls128 --bsr30 --lazy --ohh	October 4, 2019 @ 13:04

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	4915	4915	4914	4915	4915	4915	4913	4914	4914	4914	4914	4914	4910	4909	4909
4	4912	4912	4915	4913	4913	4913	4913	4914	4914	4914	4914	4912	4913	4914	4914
6	4913	4913	4913	4915	4913	4912	4912	4914	4914	4914	4914	4916	4914	4912	4912
7	4913	4913	4914	4916	4913	4913	4911	4912	4914	4914	4914	4911	4913	4913	4913
8	4914	4914	4915	4915	4914	4915	4911	4914	4914	4914	4914	4916	4914	4912	4912
9	4915	4915	4914	4913	4912	4912	4911	4914	4914	4914	4914	4912	4913	4913	4913
10	4913	4913	4914	4913	4913	4911	4912	4912	4914	4914	4914	4916	4914	4913	4913
11	4913	4913	4915	4915	4913	4912	4912	4912	4914	4914	4914	4916	4913	4913	4913
12	4913	4913	4913	4916	4913	4911	4912	4914	4914	4914	4914	4913	4915	4913	4913
13	4913	4913	4912	4914	4914	4911	4912	4914	4914	4914	4914	4916	4915	4913	4913
14	4912	4912	4913	4915	4914	4912	4913	4912	4914	4914	4914	4914	4913	4913	4913
15	4913	4913	4914	4913	4913	4912	4912	4913	4914	4914	4914	4916	4913	4912	4912
16	4913	4913	4913	4913	4912	4912	4913	4914	4914	4914	4914	4916	4913	4913	4913
17	4915	4915	4914	4914	4913	4911	4912	4914	4914	4914	4914	4916	4913	4913	4913
18	4913	4913	4912	4914	4908	4912	4912	4912	4914	4914	4914	4916	4913	4914	4914
19	4913	4913	4915	4915	4913	4911	4912	4914	4914	4914	4914	4912	4913	4913	4913
20	4913	4913	4915	4914	4914	4911	4912	4914	4914	4914	4914	4916	4913	4913	4913
21	4913	4913	4914	4915	4913	4917	4913	4913	4914	4914	4914	4914	4913	4913	4913
22	4913	4913	4915	4913	4913	4912	4911	4912	4914	4914	4914	4913	4913	4913	4913
23	4913	4913	4914	4914	4912	4913	4911	4914	4914	4914	4914	4916	4913	4913	4913
25	4913	4913	4914	4913	4913	4911	4912	4914	4914	4914	4914	4916	4914	4913	4913
30	4913	4913	4915	4915	4911	4911	4912	4914	4914	4914	4914	4915	4913	4913	4913
40	4912	4912	4914	4913	4912	4912	4912	4912	4914	4914	4914	4914	4915	4913	4913

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	4909 bytes	-3 bytes	100%
100,000	4908 bytes	-1 byte	1.16%
1,000,000	4908 bytes	–	0.29%
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)	4918 bytes	+10 bytes (+0.20%)	+1 byte
1	4917 bytes	+9 bytes (+0.18%)	–
2	4933 bytes	+25 bytes (+0.51%)	+16 bytes
3	4954 bytes	+46 bytes (+0.94%)	+37 bytes
4	4983 bytes	+75 bytes (+1.53%)	+66 bytes
5	4995 bytes	+87 bytes (+1.77%)	+78 bytes
6	5027 bytes	+119 bytes (+2.42%)	+110 bytes
7	5058 bytes	+150 bytes (+3.06%)	+141 bytes
8	5099 bytes	+191 bytes (+3.89%)	+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	-489 bytes (-9.96%)
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	4500 bytes	-408 bytes (-8.31%)
Zstandard (Wikipedia)	zstd	zstd -19	4909 bytes	+1 byte (+0.02%)
LZMA2 (Wikipedia)	xz	xz -9	4940 bytes	+32 bytes (+0.65%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	5005 bytes	+97 bytes (+1.98%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	5037 bytes	+129 bytes (+2.63%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	5257 bytes	+349 bytes (+7.11%)

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.