Choose a version:
13% The original file has 515628 bytes (503.5k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 67961 bytes (66.4k, 13%).

After GZIP compression these minified files vary in size:
Boot
  26755 bytes (26.1k)
CDN
cdnjs
  23668 bytes (23.1k)
CDN
cdnhttps
  23419 bytes (22.9k)
CDN
unpkg
  22545 bytes (22.0k)
CDN
gzip -6 (default)
  22524 bytes (22.0k)
local copy
gzip -9
  22459 bytes (21.9k)
local copy
jsdelivr
  22454 bytes (21.9k)
CDN
libdeflate -12
  21790 bytes (21.3k)
local copy
7zip -mx=9 -tgzip
  21732 bytes (21.2k)
local copy
kzip -s0 -rn -b2
  21715 bytes (21.2k)
local copy
pigz -11 -n
  21694 bytes (21.2k)
local copy
Zopfli
  21646 bytes (21.1k)
local copy
Zopfli (defluff)
  21644 bytes (21.1k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/lodash/lodash-4.13.1.min.js

You will automatically get the smallest lodash 4.13.1 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 808 bytes by using my lodash 4.13.1 Zopfli version instead of the best available CDN (3.73% smaller than jsdelivr, 21646 vs. 22454 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 --mls8 --bsr21 --lazy --ohh

(found May 25, 2016)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 8  --mls8
block splitting recursion 21  --bsr21
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 2 more bytes (21644 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://raw.githubusercontent.com/lodash/lodash/4.13.1/dist/lodash.min.js --location | md5sum
b966383b651f746af67721cc41dc1da4  -
curl --silent --compressed http://minime.stephan-brumme.com/files/lodash/lodash-4.13.1.min.zopfli.js.gz | md5sum
b966383b651f746af67721cc41dc1da4  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/lodash/lodash/4.13.1/dist/lodash.min.js --location | sha1sum
95a05c6651976f5e50873c1bb1ac8c9d0362293b  -
curl --silent --compressed http://minime.stephan-brumme.com/files/lodash/lodash-4.13.1.min.zopfli.js.gz | sha1sum
95a05c6651976f5e50873c1bb1ac8c9d0362293b  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
unpkg 22545 bytes b966383b651f746af67721cc41dc1da4 July 11, 2016 @ 16:45
jsdelivr 22454 bytes b966383b651f746af67721cc41dc1da4 (invalid)

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Boot 26755 bytes b9f2efc1470d5c7ce9eee9b951ab1539 < /**
< * @license
< * lodash lodash.com/license | Underscore.js 1.8.3 undersc [...]
< */
< ;(function(){function t(t,n){return t.set(n[0],n[1]),t}fun [...]
< return t}function i(t,n){for(var r=-1,e=t?t.length:0;++r<e [...]
< var u=-1,o=t?t.length:0;for(e&&o&&(r=t[++u]);++u<o;)r=n(r, [...]
< return-1}function y(t,n,r,e){--r;for(var u=t.length;++r<u; [...]
< })}function O(t){return function(n){return t(n)}}function [...]
< }function C(t){var n=false;if(null!=t&&typeof t.toString!= [...]
[...]
(invalid)
cdnjs 23668 bytes b9f2efc1470d5c7ce9eee9b951ab1539 < /**
< * @license
< * lodash lodash.com/license | Underscore.js 1.8.3 undersc [...]
< */
< ;(function(){function t(t,n){return t.set(n[0],n[1]),t}fun [...]
< return t}function i(t,n){for(var r=-1,e=t?t.length:0;++r<e [...]
< var u=-1,o=t?t.length:0;for(e&&o&&(r=t[++u]);++u<o;)r=n(r, [...]
< return-1}function y(t,n,r,e){--r;for(var u=t.length;++r<u; [...]
< })}function O(t){return function(n){return t(n)}}function [...]
< }function C(t){var n=false;if(null!=t&&typeof t.toString!= [...]
[...]
(invalid)
cdnhttps 23419 bytes b9f2efc1470d5c7ce9eee9b951ab1539 < /**
< * @license
< * lodash lodash.com/license | Underscore.js 1.8.3 undersc [...]
< */
< ;(function(){function t(t,n){return t.set(n[0],n[1]),t}fun [...]
< return t}function i(t,n){for(var r=-1,e=t?t.length:0;++r<e [...]
< var u=-1,o=t?t.length:0;for(e&&o&&(r=t[++u]);++u<o;)r=n(r, [...]
< return-1}function y(t,n,r,e){--r;for(var u=t.length;++r<u; [...]
< })}function O(t){return function(n){return t(n)}}function [...]
< }function C(t){var n=false;if(null!=t&&typeof t.toString!= [...]
[...]
November 22, 2016 @ 16:35

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

Other Versions

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

4.17.5, 4.17.4, 4.17.3, 4.17.2, 4.17.1, 4.17.0, 4.16.6, 4.16.5, 4.16.4, 4.16.3, 4.16.2, 4.16.1, 4.16.0, 4.15.0, 4.14.2, 4.14.1, 4.14.0, 4.13.1, 4.13.0, 4.12.0, 4.11.2, 4.11.1, 4.11.0, 4.10.0,
4.9.0, 4.8.2, 4.8.1, 4.8.0, 4.7.0, 4.6.1, 4.6.0, 4.5.1, 4.5.0, 4.4.0, 4.3.0, 4.2.1, 4.2.0, 4.1.0, 4.0.1, 4.0.0

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

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
21646 bytes -2 bytes zopfli --i1000000 --mls8 --bsr21 --lazy --ohh May 25, 2016 @ 22:51
21648 bytes -1 byte zopfli --i1000000 --mls4 --bsr18 --lazy --ohh May 25, 2016 @ 19:21
21649 bytes -1 byte zopfli --i100000 --mls4 --bsr18 --lazy --ohh May 25, 2016 @ 06:43
21650 bytes -2 bytes zopfli --i100000 --mls4 --bsr14 --lazy --ohh May 25, 2016 @ 05:23
21652 bytes -3 bytes zopfli --i10000 --mls4 --bsr18 --lazy --ohh May 25, 2016 @ 04:48
21655 bytes -1 byte zopfli --i1000 --mls4 --bsr14 --lazy --ohh May 25, 2016 @ 04:47
21656 bytes -2 bytes zopfli --i1000 --mls4 --bsr18 --lazy --ohh May 25, 2016 @ 04:46
21658 bytes -8 bytes zopfli --i1000 --mls32 --bsr18 --lazy --ohh May 25, 2016 @ 04:46
21666 bytes zopfli --i100 --mls32 --bsr17 --lazy --ohh May 25, 2016 @ 04:42

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

Most recent activity on November 22, 2016 @ 16:35.

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
21682 21682 21699 21697 21699 21698 21697 21700 21699 21702 21698 21695 21696 21693 21695
21662 21669 21667 21668 21654 21662 21681 21668 21668 21668 21667 21671 21673 21668 21667
21661 21667 21666 21667 21662 21660 21669 21666 21673 21673 21675 21669 21670 21670 21674
21657 21661 21653 21667 21653 21678 21667 21661 21663 21675 21663 21670 21665 21685 21665
21659 21666 21668 21668 21665 21671 21668 21660 21663 21674 21668 21670 21666 21678 21666
21663 21684 21650 21659 21660 21662 21665 21668 21661 21674 21663 21669 21665 21674 21669
21663 21650 21650 21663 21654 21661 21667 21662 21671 21665 21666 21664 21671 21685 21664
21658 21659 21672 21672 21671 21671 21666 21662 21663 21670 21663 21669 21665 21677 21687
21654 21660 21657 21667 21668 21667 21663 21659 21668 21675 21673 21669 21669 21684 21670
21655 21661 21659 21664 21669 21664 21676 21663 21663 21665 21663 21671 21667 21661 21677
21655 21650 21661 21671 21655 21663 21673 21660 21660 21666 21660 21670 21666 21666 21675
21655 21661 21657 21669 21655 21660 21666 21663 21663 21661 21663 21669 21666 21675 21671
21658 21658 21654 21669 21665 21664 21675 21662 21669 21667 21664 21670 21667 21678 21672
21658 21658 21661 21674 21654 21662 21666 21656 21669 21675 21669 21668 21664 21668 21667
21661 21648 21662 21667 21653 21664 21672 21662 21672 21666 21666 21668 21668 21660 21669
21655 21654 21653 21673 21663 21663 21672 21667 21666 21663 21664 21669 21664 21679 21670
21665 21659 21665 21670 21659 21654 21670 21660 21665 21672 21664 21670 21671 21661 21671
21654 21653 21646 21667 21655 21651 21672 21665 21658 21665 21662 21672 21663 21662 21669
21655 21668 21666 21663 21668 21665 21671 21667 21662 21674 21666 21670 21666 21678 21665
21663 21661 21661 21669 21671 21664 21672 21658 21669 21665 21662 21671 21664 21673 21664
21655 21655 21663 21667 21664 21664 21672 21666 21668 21665 21669 21671 21663 21660 21673
21662 21667 21653 21668 21668 21670 21662 21667 21665 21665 21664 21671 21665 21661 21665
21656 21662 21655 21664 21653 21663 21672 21666 21663 21675 21669 21672 21663 21676 21672

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 21666 bytes 100%
1,000 21655 bytes -11 bytes 100%
10,000 21652 bytes -3 bytes 100%
100,000 21649 bytes -3 bytes 2.03%
1,000,000 21646 bytes -3 bytes 0.58%
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
21729 bytes +83 bytes (+0.38%) +14 bytes
21777 bytes +131 bytes (+0.61%) +62 bytes
21715 bytes +69 bytes (+0.32%)
21729 bytes +83 bytes (+0.38%) +14 bytes
21717 bytes +71 bytes (+0.33%) +2 bytes
21734 bytes +88 bytes (+0.41%) +19 bytes
21752 bytes +106 bytes (+0.49%) +37 bytes
21779 bytes +133 bytes (+0.61%) +64 bytes
21804 bytes +158 bytes (+0.73%) +89 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 18307 bytes -3339 bytes (-15.43%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 18613 bytes -3033 bytes (-14.01%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 18982 bytes -2664 bytes (-12.31%)
Brotli (Wikipedia) brotli brotli -q 11 20346 bytes -1300 bytes (-6.01%)
LZMA2 (Wikipedia) xz xz -9 20820 bytes -826 bytes (-3.82%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 20894 bytes -752 bytes (-3.47%)
ZSTD (Wikipedia) zstd zstd -19 21499 bytes -147 bytes (-0.68%)

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 2018.
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