Choose a version:
13% The original file has 527130 bytes (514.8k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 70686 bytes (69.0k, 13%).

After GZIP compression these minified files vary in size:
Boot
  27651 bytes (27.0k)
CDN
cdnjs
  24768 bytes (24.2k)
CDN
cdnhttps
  24364 bytes (23.8k)
CDN
gzip -6 (default)
  23474 bytes (22.9k)
local copy
unpkg
  23421 bytes (22.9k)
CDN
jsdelivr
  23412 bytes (22.9k)
CDN
gzip -9
  23401 bytes (22.9k)
local copy
libdeflate -12
  22724 bytes (22.2k)
local copy
7zip -mx=9 -tgzip
  22630 bytes (22.1k)
local copy
kzip -s0 -rn -b5
  22597 bytes (22.1k)
local copy
pigz -11 -n
  22552 bytes (22.0k)
local copy
Zopfli
  22500 bytes (22.0k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/lodash/lodash-4.15.0.min.js

You will automatically get the smallest lodash 4.15.0 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 912 bytes by using my lodash 4.15.0 Zopfli version instead of the best available CDN (4.05% smaller than jsdelivr, 22500 vs. 23412 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 --bsr20 --lazy --ohh

(found August 15, 2016)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 512  --mls512
block splitting recursion 20  --bsr20
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/4.15.0/dist/lodash.min.js --location | md5sum
ae82a6e49d72ce2e21b5a30d0fc3e864  -
curl --silent --compressed http://minime.stephan-brumme.com/files/lodash/lodash-4.15.0.min.zopfli.js.gz | md5sum
ae82a6e49d72ce2e21b5a30d0fc3e864  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/lodash/lodash/4.15.0/dist/lodash.min.js --location | sha1sum
3bb5844aee605dc8debc6cdac659093b86fa10b1  -
curl --silent --compressed http://minime.stephan-brumme.com/files/lodash/lodash-4.15.0.min.zopfli.js.gz | sha1sum
3bb5844aee605dc8debc6cdac659093b86fa10b1  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
unpkg 23421 bytes ae82a6e49d72ce2e21b5a30d0fc3e864 August 12, 2016 @ 18:56
jsdelivr 23412 bytes ae82a6e49d72ce2e21b5a30d0fc3e864 (invalid)

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Boot 27651 bytes 83159a4503e660b94724ba2250ebc564 < /**
< * @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; [...]
< }return r}function E(t,n){for(var r=-1,e=Array(t);++r<t;)e [...]
< n=!!(t+"")}catch(t){}return n}function U(t){var n=-1,r=Arr [...]
[...]
August 13, 2016 @ 04:48
cdnjs 24768 bytes 83159a4503e660b94724ba2250ebc564 < /**
< * @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; [...]
< }return r}function E(t,n){for(var r=-1,e=Array(t);++r<t;)e [...]
< n=!!(t+"")}catch(t){}return n}function U(t){var n=-1,r=Arr [...]
[...]
(invalid)
cdnhttps 24364 bytes 83159a4503e660b94724ba2250ebc564 < /**
< * @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; [...]
< }return r}function E(t,n){for(var r=-1,e=Array(t);++r<t;)e [...]
< n=!!(t+"")}catch(t){}return n}function U(t){var n=-1,r=Arr [...]
[...]
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
22500 bytes -2 bytes zopfli --i1000000 --mls512 --bsr20 --lazy --ohh August 15, 2016 @ 15:02
22502 bytes -1 byte zopfli --i1000000 --mls2048 --bsr7 --lazy --ohh August 15, 2016 @ 14:33
22503 bytes -1 byte zopfli --i100000 --mls512 --bsr20 --lazy --ohh August 15, 2016 @ 10:32
22504 bytes -3 bytes zopfli --i100000 --mls2048 --bsr7 --lazy --ohh August 12, 2016 @ 19:55
22507 bytes -1 byte zopfli --i10000 --mls2048 --bsr7 --lazy --ohh August 12, 2016 @ 19:11
22508 bytes -6 bytes zopfli --i10000 --mls512 --bsr20 --lazy --ohh August 12, 2016 @ 19:07
22514 bytes -8 bytes zopfli --i1000 --mls512 --bsr20 --lazy --ohh August 12, 2016 @ 19:01
22522 bytes zopfli --i100 --mls512 --bsr20 --lazy --ohh August 12, 2016 @ 18:58

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, 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
22573 22573 22568 22570 22569 22559 22563 22568 22570 22543 22545 22546 22559 22552 22556
22543 22542 22514 22516 22524 22527 22522 22520 22523 22533 22538 22545 22535 22525 22524
22512 22514 22523 22516 22517 22517 22515 22514 22517 22515 22515 22518 22525 22528 22524
22517 22527 22524 22517 22516 22522 22512 22528 22528 22532 22502 22528 22524 22535 22521
22506 22512 22520 22518 22518 22526 22515 22517 22518 22517 22513 22529 22521 22520 22520
22513 22512 22524 22513 22515 22512 22517 22516 22512 22521 22515 22518 22522 22529 22525
22514 22514 22520 22516 22513 22518 22515 22511 22515 22520 22522 22518 22521 22523 22503
22510 22512 22541 22540 22515 22513 22519 22516 22507 22512 22523 22527 22524 22522 22516
22511 22528 22525 22521 22513 22510 22514 22510 22510 22518 22515 22521 22522 22520 22525
22512 22513 22522 22520 22519 22514 22512 22512 22514 22516 22515 22516 22522 22533 22530
22510 22516 22534 22532 22513 22517 22518 22511 22514 22524 22513 22522 22524 22521 22519
22534 22514 22533 22518 22511 22515 22512 22505 22512 22518 22515 22520 22524 22522 22521
22515 22521 22512 22517 22512 22526 22512 22512 22515 22520 22526 22521 22523 22524 22517
22516 22516 22525 22520 22512 22514 22512 22516 22515 22516 22513 22521 22523 22523 22521
22512 22511 22522 22513 22517 22518 22515 22512 22510 22516 22515 22523 22526 22525 22522
22512 22513 22511 22514 22511 22524 22518 22511 22514 22510 22521 22521 22514 22524 22515
22510 22513 22515 22517 22515 22511 22517 22510 22500 22521 22520 22520 22520 22527 22523
22515 22518 22522 22518 22514 22511 22514 22520 22515 22517 22513 22522 22524 22515 22526
22512 22510 22518 22516 22514 22520 22516 22517 22519 22518 22522 22518 22528 22530 22515
22513 22515 22516 22517 22513 22513 22510 22516 22517 22516 22513 22518 22522 22520 22520
22513 22524 22513 22511 22513 22512 22515 22517 22512 22513 22515 22520 22518 22516 22518
22510 22515 22520 22517 22516 22512 22511 22513 22520 22516 22516 22518 22526 22518 22519
22511 22510 22520 22524 22514 22523 22514 22511 22515 22518 22514 22520 22519 22519 22518

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 22522 bytes 100%
1,000 22514 bytes -8 bytes 100%
10,000 22507 bytes -7 bytes 100%
100,000 22503 bytes -4 bytes 1.74%
1,000,000 22500 bytes -3 bytes 0.87%
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
22600 bytes +100 bytes (+0.44%) +3 bytes
22737 bytes +237 bytes (+1.05%) +140 bytes
22628 bytes +128 bytes (+0.57%) +31 bytes
22622 bytes +122 bytes (+0.54%) +25 bytes
22600 bytes +100 bytes (+0.44%) +3 bytes
22597 bytes +97 bytes (+0.43%)
22624 bytes +124 bytes (+0.55%) +27 bytes
22647 bytes +147 bytes (+0.65%) +50 bytes
22660 bytes +160 bytes (+0.71%) +63 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 18939 bytes -3561 bytes (-15.83%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 19497 bytes -3003 bytes (-13.35%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 19848 bytes -2652 bytes (-11.79%)
Brotli (Wikipedia) brotli brotli -q 11 21020 bytes -1480 bytes (-6.58%)
LZMA2 (Wikipedia) xz xz -9 21544 bytes -956 bytes (-4.25%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 21858 bytes -642 bytes (-2.85%)
ZSTD (Wikipedia) zstd zstd -19 22409 bytes -91 bytes (-0.40%)

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