React 17.0.2 - as small as it gets (near-perfect GZIP compression)

Choose a version:

The original file has 105096 bytes (102.6k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 11440 bytes (11.2k, 11%).

After GZIP compression these minified files vary in size:

Boot	4590 bytes (4.5k)	CDN
cdnjs	4590 bytes (4.5k)	CDN
gzip -9	4589 bytes (4.5k)	local copy
gzip -6 (default)	4588 bytes (4.5k)	local copy
zultra	4499 bytes (4.4k)	local copy
libdeflate -12	4493 bytes (4.4k)	local copy
7zip -mx=9 -tgzip	4492 bytes (4.4k)	local copy
kzip -s0 -rn -b1	4489 bytes (4.4k)	local copy
pigz -11 -n	4488 bytes (4.4k)	local copy
Zopfli	4487 bytes (4.4k)	local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/react/react-17.0.2.min.js (or via HTTPS)

You will automatically get the smallest React 17.0.2 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 103 bytes by using my React 17.0.2 Zopfli version instead of the best available CDN (2.30% smaller than cdnjs, 4487 vs. 4590 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 --i1000 --mb8 --mls1024 --bsr2 --lazy --ohh

(found March 24, 2021)

Description	Value	Parameter
iterations	1000	--i1000
maximum blocks	8	--mb8
maximum length score	1024	--mls1024
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-17.0.2.min.js --location | md5sum
61699b70cf57abe63fdf5f4007d36ec1 -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-17.0.2.min.zopfli.js.gz | md5sum
61699b70cf57abe63fdf5f4007d36ec1 -

SHA1:
curl --silent --compressed https://fb.me/react-17.0.2.min.js --location | sha1sum
6c05189cc2d08bb2a7609c002f0675c9c670d362 -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-17.0.2.min.zopfli.js.gz | sha1sum
6c05189cc2d08bb2a7609c002f0675c9c670d362 -

All listed CDNs deliver identical contents:

CDN	Size (compressed)	MD5 (uncompressed)	Timestamp
Boot	4590 bytes	61699b70cf57abe63fdf5f4007d36ec1	March 23, 2021 @ 01:27
cdnjs	4590 bytes	61699b70cf57abe63fdf5f4007d36ec1	March 23, 2021 @ 01:27

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
4487 bytes	-1 byte	zopfli --i1000 --mls1024 --bsr2 --lazy --ohh	March 24, 2021 @ 12:04
4488 bytes	–	zopfli --i100 --mls16 --bsr6 --lazy --ohh	March 24, 2021 @ 11:56

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on March 26, 2021 @ 21:14.

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	4487	4487	4487	4487	4487	4497	4487	4487	4487	4487	4487	4487	4494	4499	4499
4	4487	4487	4487	4487	4497	4496	4487	4487	4487	4487	4487	4487	4493	4494	4494
6	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4492	4500	4500
7	4487	4487	4487	4487	4493	4492	4487	4487	4487	4487	4487	4487	4494	4499	4499
8	4487	4487	4487	4487	4487	4497	4487	4487	4487	4487	4487	4487	4493	4499	4499
9	4487	4487	4487	4487	4487	4491	4487	4487	4487	4487	4487	4487	4494	4493	4493
10	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4499	4499	4499
11	4487	4487	4487	4487	4487	4491	4487	4487	4487	4487	4487	4487	4492	4499	4499
12	4487	4487	4487	4487	4497	4487	4487	4487	4487	4487	4487	4487	4492	4499	4499
13	4487	4487	4487	4487	4493	4491	4487	4487	4487	4487	4487	4487	4492	4500	4500
14	4487	4487	4487	4487	4487	4491	4487	4487	4487	4487	4487	4487	4492	4491	4491
15	4487	4487	4487	4487	4487	4491	4487	4487	4487	4487	4487	4487	4494	4499	4499
16	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4492	4493	4493
17	4487	4487	4487	4487	4487	4491	4487	4487	4487	4487	4487	4487	4492	4499	4499
18	4487	4487	4487	4487	4497	4492	4487	4487	4487	4487	4487	4487	4492	4492	4492
19	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4494	4500	4500
20	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4492	4500	4500
21	4487	4487	4487	4487	4493	4492	4487	4487	4487	4487	4487	4487	4492	4494	4494
22	4487	4487	4487	4487	4493	4497	4487	4487	4487	4487	4487	4487	4492	4499	4499
23	4487	4487	4487	4487	4496	4491	4487	4487	4487	4487	4487	4487	4494	4499	4499
25	4487	4487	4487	4487	4493	4492	4487	4487	4487	4487	4487	4487	4494	4500	4500
30	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4499	4499	4499
40	4487	4487	4487	4487	4487	4492	4487	4487	4487	4487	4487	4487	4492	4499	4499

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	4488 bytes	–	100%
1,000	4487 bytes	-1 byte	100%
10,000	4487 bytes	–	100%
100,000	4487 bytes	–	71.01%
1,000,000	4487 bytes	–	71.01%
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)	4489 bytes	+2 bytes (+0.04%)	–
1	4489 bytes	+2 bytes (+0.04%)	–
2	4508 bytes	+21 bytes (+0.47%)	+19 bytes
3	4534 bytes	+47 bytes (+1.05%)	+45 bytes
4	4550 bytes	+63 bytes (+1.40%)	+61 bytes
5	4589 bytes	+102 bytes (+2.27%)	+100 bytes
6	4628 bytes	+141 bytes (+3.14%)	+139 bytes
7	4660 bytes	+173 bytes (+3.86%)	+171 bytes
8	4690 bytes	+203 bytes (+4.52%)	+201 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	4019 bytes	-468 bytes (-10.43%)
RAR (proprietary)	RAR	rar a -m5 -md64m -mc63:128t -mt1	4147 bytes	-340 bytes (-7.58%)
Zstandard (Wikipedia)	zstd	zstd -19	4492 bytes	+5 bytes (+0.11%)
LZMA2 (Wikipedia)	xz	xz -9	4536 bytes	+49 bytes (+1.09%)
PPMd (Wikipedia)	7zip	7za a -mx=9 -m0=ppmd	4570 bytes	+83 bytes (+1.85%)
Burrows-Wheeler transform (Wikipedia)	bzip2	bzip2 -9	4643 bytes	+156 bytes (+3.48%)
ZPAQ (Wikipedia)	zpaq	zpaq -method 69	4951 bytes	+464 bytes (+10.34%)

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.