Choose a version:
32% The original file has 268039 bytes (261.8k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 86659 bytes (84.6k, 32%).

After GZIP compression these minified files vary in size:
cdnjs
  30388 bytes (29.7k)
CDN, direct link
Google
  30306 bytes (29.6k)
CDN, direct link
Microsoft
  30217 bytes (29.5k)
CDN, direct link
gzip -6 (default)
  30198 bytes (29.5k)
local copy
unpkg
  30177 bytes (29.5k)
CDN, direct link
gzip -9
  30145 bytes (29.4k)
local copy
jsdelivr
  30140 bytes (29.4k)
CDN, direct link
7zip -mx=9 -tgzip
  29190 bytes (28.5k)
local copy
libdeflate -12
  29122 bytes (28.4k)
local copy
pigz -11 -n
  29104 bytes (28.4k)
local copy
kzip -s0 -rn -b2
  29087 bytes (28.4k)
local copy
Zopfli
  29072 bytes (28.4k)
local copy
Zopfli (defluff)
  29071 bytes (28.4k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/jquery/jquery-3.2.1.min.js

You will automatically get the smallest jQuery 3.2.1 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 1068 bytes by using my jQuery 3.2.1 Zopfli version instead of the best available CDN (3.67% smaller than jsdelivr, 29072 vs. 30140 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 --i1000000 --mb8 --mls512 --bsr30 --lazy --ohh

(found March 29, 2017)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 512  --mls512
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

Even Smaller Files Thanks To Defluff

Zopfli's output can be further optimized by the defluff tool.
In this particular case, defluff saves 1 more byte (29071 bytes).

Verify file integrity

After decompression, my uncompressed files are identical to the original ones:

MD5:
curl --silent --compressed http://code.jquery.com/jquery-3.2.1.min.js --location | md5sum
c9f5aeeca3ad37bf2aa006139b935f0a  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-3.2.1.min.zopfli.js.gz | md5sum
c9f5aeeca3ad37bf2aa006139b935f0a  -

SHA1:
curl --silent --compressed http://code.jquery.com/jquery-3.2.1.min.js --location | sha1sum
1055018c28ab41087ef9ccefe411606893dabea2  -
curl --silent --compressed http://minime.stephan-brumme.com/files/jquery/jquery-3.2.1.min.zopfli.js.gz | sha1sum
1055018c28ab41087ef9ccefe411606893dabea2  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
cdnjs 30388 bytes c9f5aeeca3ad37bf2aa006139b935f0a March 20, 2017 @ 20:18
Google 30306 bytes c9f5aeeca3ad37bf2aa006139b935f0a March 24, 2017 @ 21:55
Microsoft 30217 bytes c9f5aeeca3ad37bf2aa006139b935f0a March 20, 2017 @ 20:54
unpkg 30177 bytes c9f5aeeca3ad37bf2aa006139b935f0a March 22, 2017 @ 09:08
jsdelivr 30140 bytes c9f5aeeca3ad37bf2aa006139b935f0a March 20, 2017 @ 20:34

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

Other Versions

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

3.2.1, 3.2.0,
3.1.1, 3.1.0,
3.0.0,
2.2.4, 2.2.3, 2.2.2, 2.2.1, 2.2.0,
2.1.4, 2.1.3, 2.1.2, 2.1.1, 2.1.0,
2.0.3, 2.0.2, 2.0.1, 2.0.0,
1.12.4, 1.12.3, 1.12.2, 1.12.1, 1.12.0,
1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.2, 1.10.1, 1.10.0,
1.9.1, 1.9.0,
1.8.3, 1.8.2, 1.8.1, 1.8.0,
1.7.2, 1.7.1, 1.7.0,
1.6.4, 1.6.3, 1.6.2, 1.6.1, 1.6,
1.5.2, 1.5.1, 1.5,
1.4.4, 1.4.3, 1.4.2, 1.4.1, 1.4,
1.3.2, 1.3.1, 1.3,
1.2.6, 1.2.5, 1.2.4, 1.2.3, 1.2.2, 1.2.1, 1.2,
1.1.4, 1.1.3, 1.1.2, 1.1.1, 1.1,
1.0.4, 1.0.3, 1.0.2, 1.0.1, 1.0

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Dojo, Ember, Knockout, lodash, React, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
29072 bytes -1 byte zopfli --i1000000 --mls512 --bsr30 --lazy --ohh March 29, 2017 @ 12:06
29073 bytes -2 bytes zopfli --i100000 --mls512 --bsr30 --lazy --ohh March 29, 2017 @ 07:14
29075 bytes -2 bytes zopfli --i10000 --mls512 --bsr30 --lazy --ohh March 28, 2017 @ 23:56
29077 bytes zopfli --i100 --mls512 --bsr20 --lazy --ohh March 28, 2017 @ 22:56

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

Most recent activity on March 30, 2017 @ 00:58.

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
29097 29097 29098 29098 29098 29095 29097 29099 29080 29080 29084 29085 29082 29083 29092
29094 29093 29093 29100 29101 29102 29099 29096 29095 29096 29077 29078 29080 29088 29099
29092 29096 29097 29094 29088 29088 29086 29088 29087 29086 29072 29079 29079 29077 29079
29091 29094 29094 29112 29109 29093 29102 29087 29078 29077 29086 29079 29079 29077 29079
29096 29092 29094 29089 29085 29086 29085 29088 29078 29080 29078 29079 29079 29080 29079
29096 29093 29093 29087 29088 29100 29094 29103 29095 29093 29077 29079 29078 29088 29079
29095 29096 29094 29096 29087 29095 29087 29086 29094 29077 29079 29079 29077 29086 29079
29094 29095 29093 29095 29110 29096 29088 29087 29088 29077 29078 29079 29079 29085 29079
29094 29097 29095 29087 29085 29086 29101 29086 29085 29077 29079 29082 29078 29077 29079
29108 29094 29094 29091 29086 29086 29086 29088 29095 29078 29077 29082 29078 29079 29085
29107 29093 29095 29087 29086 29085 29086 29106 29082 29077 29079 29080 29079 29078 29079
29094 29096 29094 29088 29089 29085 29103 29087 29097 29078 29079 29082 29079 29077 29079
29095 29094 29095 29086 29087 29086 29087 29087 29097 29077 29078 29082 29079 29077 29079
29096 29096 29095 29090 29087 29093 29101 29088 29087 29086 29072 29079 29079 29079 29079
29094 29095 29094 29095 29088 29088 29088 29088 29087 29086 29078 29079 29079 29077 29079
29095 29095 29094 29095 29086 29096 29086 29087 29087 29077 29077 29080 29079 29077 29079
29088 29105 29094 29087 29085 29094 29085 29086 29072 29078 29077 29082 29079 29079 29077
29094 29095 29094 29088 29086 29097 29086 29088 29086 29086 29079 29077 29078 29079 29079
29094 29093 29095 29089 29087 29086 29088 29086 29085 29086 29078 29082 29079 29077 29079
29094 29096 29093 29102 29089 29095 29101 29088 29086 29086 29074 29080 29078 29077 29079
29094 29095 29094 29090 29089 29088 29086 29086 29086 29086 29072 29082 29078 29079 29078
29094 29091 29099 29087 29087 29085 29085 29086 29072 29086 29079 29082 29079 29078 29079
29096 29093 29094 29094 29096 29098 29102 29102 29077 29078 29078 29079 29079 29085 29079

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 29077 bytes 100%
1,000 29077 bytes 100%
10,000 29075 bytes -2 bytes 100%
100,000 29073 bytes -2 bytes 1.74%
1,000,000 29072 bytes -1 byte 1.45%
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
29187 bytes +115 bytes (+0.40%) +100 bytes
29187 bytes +115 bytes (+0.40%) +100 bytes
29087 bytes +15 bytes (+0.05%)
29101 bytes +29 bytes (+0.10%) +14 bytes
29107 bytes +35 bytes (+0.12%) +20 bytes
29165 bytes +93 bytes (+0.32%) +78 bytes
29193 bytes +121 bytes (+0.42%) +106 bytes
29238 bytes +166 bytes (+0.57%) +151 bytes
29262 bytes +190 bytes (+0.65%) +175 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 24146 bytes -4926 bytes (-16.94%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 24672 bytes -4400 bytes (-15.13%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 26140 bytes -2932 bytes (-10.09%)
Brotli (Wikipedia) brotli brotli -q 11 27220 bytes -1852 bytes (-6.37%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 27564 bytes -1508 bytes (-5.19%)
LZMA2 (Wikipedia) xz xz -9 28320 bytes -752 bytes (-2.59%)
ZSTD (Wikipedia) zstd zstd -19 28882 bytes -190 bytes (-0.65%)

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 2017.
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