Choose a version:
14% The original file has 460193 bytes (449.4k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 62233 bytes (60.8k, 14%).

After GZIP compression these minified files vary in size:
Boot
  36764 bytes (35.9k)
CDN
cdnjs
  30375 bytes (29.7k)
CDN
cdnhttps
  29908 bytes (29.2k)
CDN
gzip -6 (default)
  20844 bytes (20.4k)
local copy
jsdelivr
  20781 bytes (20.3k)
CDN
gzip -9
  20776 bytes (20.3k)
local copy
7zip -mx=9 -tgzip
  20161 bytes (19.7k)
local copy
libdeflate -12
  20149 bytes (19.7k)
local copy
kzip -s0 -rn -b2
  20073 bytes (19.6k)
local copy
pigz -11 -n
  20024 bytes (19.6k)
local copy
Zopfli
  19996 bytes (19.5k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/lodash/lodash-4.0.1.min.js

You will automatically get the smallest lodash 4.0.1 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 785 bytes by using my lodash 4.0.1 Zopfli version instead of the best available CDN (3.93% smaller than jsdelivr, 19996 vs. 20781 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 --i100000 --mb8 --mls16 --bsr7 --lazy --ohh

(found April 13, 2016)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 16  --mls16
block splitting recursion 7  --bsr7
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://raw.githubusercontent.com/lodash/lodash/4.0.1/dist/lodash.min.js --location | md5sum
fbf95292455903e49977ad291bbb70d4  -
curl --silent --compressed http://minime.stephan-brumme.com/files/lodash/lodash-4.0.1.min.zopfli.js.gz | md5sum
fbf95292455903e49977ad291bbb70d4  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/lodash/lodash/4.0.1/dist/lodash.min.js --location | sha1sum
70018a1a9ca2f3cf5f89fb7a5baa826bc60f8e82  -
curl --silent --compressed http://minime.stephan-brumme.com/files/lodash/lodash-4.0.1.min.zopfli.js.gz | sha1sum
70018a1a9ca2f3cf5f89fb7a5baa826bc60f8e82  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
jsdelivr 20781 bytes fbf95292455903e49977ad291bbb70d4 (invalid)

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Boot 36764 bytes 06c1a97e9d5651d586942afe356272fe < /**
< * @license
< * lodash 4.0.1 (Custom Build) lodash.com/license | Unders [...]
< * Build: `lodash -o ./dist/lodash.js`
< */
< ;(function(){function n(n,t){return n.set(t[0],t[1]),n}fun [...]
< }return o}function i(n,t){return!!n.length&&-1<v(n,t,0)}fu [...]
< return false}function p(n,t,r){for(var e=-1,u=n.length;++e [...]
< var r=n.length;for(n.sort(t);r--;)n[r]=n[r].c;return n}fun [...]
< return r}function E(n){return n&&n.Object===Object?n:null} [...]
[...]
(invalid)
cdnjs 30375 bytes 06c1a97e9d5651d586942afe356272fe < /**
< * @license
< * lodash 4.0.1 (Custom Build) lodash.com/license | Unders [...]
< * Build: `lodash -o ./dist/lodash.js`
< */
< ;(function(){function n(n,t){return n.set(t[0],t[1]),n}fun [...]
< }return o}function i(n,t){return!!n.length&&-1<v(n,t,0)}fu [...]
< return false}function p(n,t,r){for(var e=-1,u=n.length;++e [...]
< var r=n.length;for(n.sort(t);r--;)n[r]=n[r].c;return n}fun [...]
< return r}function E(n){return n&&n.Object===Object?n:null} [...]
[...]
(invalid)
cdnhttps 29908 bytes 06c1a97e9d5651d586942afe356272fe < /**
< * @license
< * lodash 4.0.1 (Custom Build) lodash.com/license | Unders [...]
< * Build: `lodash -o ./dist/lodash.js`
< */
< ;(function(){function n(n,t){return n.set(t[0],t[1]),n}fun [...]
< }return o}function i(n,t){return!!n.length&&-1<v(n,t,0)}fu [...]
< return false}function p(n,t,r){for(var e=-1,u=n.length;++e [...]
< var r=n.length;for(n.sort(t);r--;)n[r]=n[r].c;return n}fun [...]
< return r}function E(n){return n&&n.Object===Object?n:null} [...]
[...]
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
19996 bytes -1 byte zopfli --i100000 --mls16 --bsr7 --lazy --ohh April 13, 2016 @ 11:53
19997 bytes -4 bytes zopfli --i10000 --mls16 --bsr7 --lazy --ohh April 12, 2016 @ 16:12
20001 bytes -4 bytes zopfli --i1000 --mls16 --bsr7 --lazy --ohh April 12, 2016 @ 16:09
20005 bytes zopfli --i100 --mls16 --bsr7 --lazy --ohh April 12, 2016 @ 02:58

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 or 100,000.
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
20029 20032 20031 20035 20013 20011 20050 20046 20045 20022 20034 20026 20020 20039 20043
20005 20009 20010 20006 20009 20012 20018 20026 20013 20027 20013 20010 20013 20024 20014
20004 20006 20009 20007 20003 20024 20022 20023 20022 20018 20015 20017 20004 20010 20012
20005 20006 20006 19996 20001 20004 20006 20013 20010 20017 20028 20019 20018 20010 20018
20002 20015 20003 20000 20002 20011 20005 20006 20007 20002 20011 20021 20003 20006 20019
20006 20003 20009 19999 20004 20032 20005 20011 20027 20015 20006 20019 20001 20019 20012
20002 20002 20005 20000 20007 20011 20007 20019 20009 20018 20010 20024 20018 20009 20006
20004 20002 20012 19998 20004 20010 20031 20006 20019 20005 20026 20018 20018 20022 20007
20003 20009 20009 20012 20002 20006 20005 20014 20005 20007 20013 20020 20020 20009 20012
20009 20005 20007 20006 20002 20007 20010 20011 20020 20014 20016 20009 20003 20013 20012
20002 20003 20010 19999 20001 20006 20007 20012 20020 20015 20014 20006 20001 20013 20007
20003 20005 20006 20004 20001 20004 20004 20012 20020 20007 20022 20016 20018 20013 20020
20002 20002 20008 20001 20000 20007 20005 20012 20020 20006 20019 20019 19999 20014 20004
20004 20006 20008 20000 20001 20005 20000 20011 20020 20018 20009 20018 20014 20023 20008
20003 20003 20005 20001 20002 20011 20007 20011 20019 20018 20005 20020 20018 20011 20005
20010 20002 20002 19998 20007 20010 19999 20011 20018 20018 20008 20021 19998 20013 20007
20001 20003 20006 20002 20005 20012 20006 20010 20007 20002 20008 20023 20018 20025 20016
20005 20001 20001 20001 20003 20011 19998 20010 20018 20016 20012 20022 20018 20012 20011
20003 20001 20005 20002 20001 20014 20005 20009 20011 20014 20008 20019 20014 20023 20011
20004 20002 20007 20001 20004 20016 20001 20013 20010 20001 20022 20022 20002 20011 20011
20004 20004 20007 20006 20002 20004 20000 20009 20011 20016 20022 20022 20018 20005 20012
20003 20002 20002 19999 20002 20015 20009 20003 20005 20006 20021 20020 20017 20010 20019
20011 20002 20007 20000 20002 20010 20007 20011 20013 20002 20007 20007 20017 20023 20011

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 20005 bytes 100%
1,000 20000 bytes -5 bytes 100%
10,000 19997 bytes -3 bytes 100%
100,000 19996 bytes -1 byte 0.29%
1,000,000
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
20082 bytes +86 bytes (+0.43%) +9 bytes
20145 bytes +149 bytes (+0.75%) +72 bytes
20073 bytes +77 bytes (+0.39%)
20081 bytes +85 bytes (+0.43%) +8 bytes
20087 bytes +91 bytes (+0.46%) +14 bytes
20102 bytes +106 bytes (+0.53%) +29 bytes
20124 bytes +128 bytes (+0.64%) +51 bytes
20139 bytes +143 bytes (+0.72%) +66 bytes
20155 bytes +159 bytes (+0.80%) +82 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 17041 bytes -2955 bytes (-14.78%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 17283 bytes -2713 bytes (-13.57%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 18334 bytes -1662 bytes (-8.31%)
Brotli (Wikipedia) brotli brotli -q 11 18819 bytes -1177 bytes (-5.89%)
LZMA2 (Wikipedia) xz xz -9 19284 bytes -712 bytes (-3.56%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 19381 bytes -615 bytes (-3.08%)
ZSTD (Wikipedia) zstd zstd -19 19905 bytes -91 bytes (-0.46%)

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