Choose a version:
10% The original file has 111030 bytes (108.4k) 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, 10%).

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)
  4587 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
  4490 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-17.0.1.min.js (or via HTTPS)

You will automatically get the smallest React 17.0.1 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 103 bytes by using my React 17.0.1 Zopfli version instead of the best available CDN (2.30% smaller than cdnjs, 4487 vs. 4590 bytes):
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 --mls64 --bsr12 --lazy --ohh

(found October 22, 2020)
Description Value Parameter
iterations 1000  --i1000
maximum blocks 8  --mb8
maximum length score 64  --mls64
block splitting recursion 12  --bsr12
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-17.0.1.min.js --location | md5sum
0da24faef1b203057592c836d1e60ece  -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-17.0.1.min.zopfli.js.gz | md5sum
0da24faef1b203057592c836d1e60ece  -

SHA1:
curl --silent --compressed https://fb.me/react-17.0.1.min.js --location | sha1sum
6c8d054556748693f05771e6a6e260790e213d59  -
curl --silent --compressed https://minime.stephan-brumme.com/files/react/react-17.0.1.min.zopfli.js.gz | sha1sum
6c8d054556748693f05771e6a6e260790e213d59  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 4590 bytes 0da24faef1b203057592c836d1e60ece October 22, 2020 @ 16:38
cdnjs 4590 bytes 0da24faef1b203057592c836d1e60ece October 22, 2020 @ 16:38

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

Available React versions at minime.stephan-brumme.com:

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 --mls64 --bsr12 --lazy --ohh October 22, 2020 @ 18:21
4488 bytes zopfli --i100 --mls2048 --bsr16 --lazy --ohh October 22, 2020 @ 18:09

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

Most recent activity on October 26, 2020 @ 11:37.

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
4487 4487 4487 4487 4487 4497 4487 4487 4487 4487 4487 4487 4494 4499 4499
4487 4487 4487 4487 4497 4496 4487 4487 4487 4487 4487 4487 4493 4494 4494
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4492 4500 4500
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4494 4499 4499
4487 4487 4487 4487 4487 4497 4487 4487 4487 4487 4487 4487 4494 4499 4499
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4494 4494 4494
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4494 4494 4494
4487 4487 4487 4487 4497 4491 4487 4487 4487 4487 4487 4487 4492 4499 4499
4487 4487 4487 4487 4497 4487 4487 4487 4487 4487 4487 4487 4492 4499 4499
4487 4487 4487 4487 4497 4491 4487 4487 4487 4487 4487 4487 4499 4500 4500
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4492 4491 4491
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4494 4499 4499
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4493 4493 4493
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4492 4499 4499
4487 4487 4487 4487 4497 4492 4487 4487 4487 4487 4487 4487 4492 4492 4492
4487 4487 4487 4487 4487 4492 4487 4487 4487 4487 4487 4487 4494 4499 4499
4487 4487 4487 4487 4497 4492 4487 4487 4487 4487 4487 4487 4500 4500 4500
4487 4487 4487 4487 4491 4492 4487 4487 4487 4487 4487 4487 4494 4494 4494
4487 4487 4487 4487 4497 4498 4487 4487 4487 4487 4487 4487 4492 4499 4499
4487 4487 4487 4487 4496 4492 4487 4487 4487 4487 4487 4487 4494 4499 4499
4487 4487 4487 4487 4497 4492 4487 4487 4487 4487 4487 4487 4492 4499 4499
4487 4487 4487 4487 4487 4491 4487 4487 4487 4487 4487 4487 4499 4499 4499
4487 4487 4487 4487 4487 4491 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 70.72%
1,000,000 4487 bytes 70.72%
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
4490 bytes +3 bytes (+0.07%)
4490 bytes +3 bytes (+0.07%)
4507 bytes +20 bytes (+0.45%) +17 bytes
4533 bytes +46 bytes (+1.03%) +43 bytes
4550 bytes +63 bytes (+1.40%) +60 bytes
4588 bytes +101 bytes (+2.25%) +98 bytes
4627 bytes +140 bytes (+3.12%) +137 bytes
4659 bytes +172 bytes (+3.83%) +169 bytes
4689 bytes +202 bytes (+4.50%) +199 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 4149 bytes -338 bytes (-7.53%)
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 4641 bytes +154 bytes (+3.43%)
ZPAQ (Wikipedia) zpaq zpaq -method 69 4952 bytes +465 bytes (+10.36%)

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):


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 2020.
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.