Choose a version:
13% The original file has 539618 bytes (527.0k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 72781 bytes (71.1k, 13%).

After GZIP compression these minified files vary in size:
Boot
  28721 bytes (28.0k)
CDN
cdnjs
  25597 bytes (25.0k)
CDN
unpkg
  24267 bytes (23.7k)
CDN
gzip -6 (default)
  24219 bytes (23.7k)
local copy
jsdelivr
  24160 bytes (23.6k)
CDN
gzip -9
  24156 bytes (23.6k)
local copy
7zip -mx=9 -tgzip
  23347 bytes (22.8k)
local copy
libdeflate -12
  23319 bytes (22.8k)
local copy
kzip -s0 -rn -b3
  23243 bytes (22.7k)
local copy
pigz -11 -n
  23211 bytes (22.7k)
local copy
Zopfli
  23177 bytes (22.6k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/lodash/lodash-4.17.3.min.js (or via HTTPS)

You will automatically get the smallest lodash 4.17.3 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 983 bytes by using my lodash 4.17.3 Zopfli version instead of the best available CDN (4.24% smaller than jsdelivr, 23177 vs. 24160 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 --mls2048 --bsr23 --lazy --ohh

(found December 26, 2016)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 2048  --mls2048
block splitting recursion 23  --bsr23
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/4.17.3/dist/lodash.min.js --location | md5sum
77b6577e047c3a4c8f5969deabfc1368  -
curl --silent --compressed https://minime.stephan-brumme.com/files/lodash/lodash-4.17.3.min.zopfli.js.gz | md5sum
77b6577e047c3a4c8f5969deabfc1368  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/lodash/lodash/4.17.3/dist/lodash.min.js --location | sha1sum
23a29bee6b653dacf36848c5d9c66db0c0bf7faf  -
curl --silent --compressed https://minime.stephan-brumme.com/files/lodash/lodash-4.17.3.min.zopfli.js.gz | sha1sum
23a29bee6b653dacf36848c5d9c66db0c0bf7faf  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
unpkg 24267 bytes 77b6577e047c3a4c8f5969deabfc1368 December 26, 2016 @ 07:34
jsdelivr 24160 bytes 77b6577e047c3a4c8f5969deabfc1368 (invalid)

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Boot 28721 bytes 44dc256591a82b3ad4bc54e2803e7988 < /**
< * @license
< * Lodash lodash.com/license | Underscore.js 1.8.3 undersc [...]
< */
< ;(function(){function n(n,t){return n.set(t[0],t[1]),n}fun [...]
< return n}function o(n,t){for(var r=-1,e=null==n?0:n.length [...]
< return n}function h(n,t,r,e){var u=-1,i=null==n?0:n.length [...]
< --r;for(var e=n.length;++r<e;)if(n[r]===t){n=r;break n}n=- [...]
< return n}function k(n,t){for(var r,e=-1,u=n.length;++e<u;) [...]
< return"\\"+Tn[n]}function L(n){var t=-1,r=Array(n.size);re [...]
[...]
(invalid)
cdnjs 25597 bytes 44dc256591a82b3ad4bc54e2803e7988 < /**
< * @license
< * Lodash lodash.com/license | Underscore.js 1.8.3 undersc [...]
< */
< ;(function(){function n(n,t){return n.set(t[0],t[1]),n}fun [...]
< return n}function o(n,t){for(var r=-1,e=null==n?0:n.length [...]
< return n}function h(n,t,r,e){var u=-1,i=null==n?0:n.length [...]
< --r;for(var e=n.length;++r<e;)if(n[r]===t){n=r;break n}n=- [...]
< return n}function k(n,t){for(var r,e=-1,u=n.length;++e<u;) [...]
< return"\\"+Tn[n]}function L(n){var t=-1,r=Array(n.size);re [...]
[...]
(invalid)

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

Other Versions

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

4.17.11, 4.17.10, 4.17.9, 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
23177 bytes -2 bytes zopfli --i1000000 --mls2048 --bsr23 --lazy --ohh December 26, 2016 @ 21:16
23179 bytes -1 byte zopfli --i100000 --mls2048 --bsr23 --lazy --ohh December 26, 2016 @ 09:23
23180 bytes -3 bytes zopfli --i100000 --mls1024 --bsr18 --lazy --ohh December 26, 2016 @ 08:24
23183 bytes -1 byte zopfli --i10000 --mls1024 --bsr18 --lazy --ohh December 26, 2016 @ 07:50
23184 bytes -1 byte zopfli --i1000 --mls2048 --bsr15 --lazy --ohh December 26, 2016 @ 07:44
23185 bytes -5 bytes zopfli --i1000 --mls32 --bsr40 --lazy --ohh December 26, 2016 @ 07:43
23190 bytes zopfli --i100 --mls4096 --bsr14 --lazy --ohh December 26, 2016 @ 07:37

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

Most recent activity on January 25, 2017 @ 15:29.

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
23235 23236 23233 23231 23229 23229 23222 23224 23225 23229 23233 23226 23230 23235 23230
23205 23222 23218 23221 23221 23203 23204 23205 23202 23203 23206 23206 23202 23234 23205
23207 23188 23192 23203 23193 23192 23194 23196 23196 23184 23187 23210 23187 23192 23197
23193 23184 23192 23196 23192 23192 23202 23202 23202 23195 23184 23187 23212 23189 23189
23192 23194 23193 23189 23207 23194 23189 23205 23202 23194 23180 23204 23191 23208 23190
23191 23193 23193 23190 23184 23192 23194 23202 23193 23190 23193 23207 23194 23200 23215
23193 23191 23196 23191 23205 23197 23194 23201 23200 23202 23205 23192 23184 23199 23192
23192 23185 23184 23190 23184 23206 23193 23205 23191 23191 23177 23184 23192 23193 23205
23190 23187 23192 23212 23191 23194 23194 23190 23192 23192 23186 23194 23191 23199 23190
23211 23204 23183 23201 23221 23194 23208 23203 23203 23183 23192 23205 23193 23208 23204
23202 23193 23196 23190 23191 23196 23194 23194 23195 23192 23190 23183 23191 23199 23188
23193 23193 23191 23189 23191 23192 23202 23203 23191 23191 23181 23196 23200 23180 23192
23202 23201 23202 23196 23185 23194 23187 23200 23188 23193 23185 23196 23192 23190 23189
23191 23192 23192 23197 23192 23192 23185 23194 23192 23193 23184 23195 23192 23208 23190
23191 23192 23192 23190 23190 23192 23185 23204 23193 23180 23195 23197 23193 23206 23193
23193 23185 23191 23191 23202 23193 23202 23202 23192 23196 23194 23197 23192 23207 23190
23192 23193 23191 23189 23200 23194 23194 23202 23196 23193 23184 23206 23201 23212 23190
23194 23194 23193 23229 23192 23195 23192 23195 23196 23200 23184 23196 23192 23190 23192
23204 23194 23193 23199 23202 23194 23194 23190 23191 23180 23188 23192 23192 23192 23189
23191 23182 23191 23188 23193 23203 23195 23202 23191 23193 23177 23198 23193 23201 23192
23193 23194 23191 23243 23192 23194 23194 23203 23202 23183 23180 23209 23190 23201 23191
23191 23183 23194 23191 23192 23194 23195 23191 23192 23198 23184 23202 23191 23200 23189
23190 23203 23194 23214 23183 23195 23195 23193 23193 23195 23185 23206 23194 23206 23192

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 23190 bytes 100%
1,000 23184 bytes -6 bytes 100%
10,000 23180 bytes -4 bytes 100%
100,000 23179 bytes -1 byte 2.61%
1,000,000 23177 bytes -2 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
23266 bytes +89 bytes (+0.38%) +23 bytes
23432 bytes +255 bytes (+1.10%) +189 bytes
23308 bytes +131 bytes (+0.57%) +65 bytes
23243 bytes +66 bytes (+0.28%)
23268 bytes +91 bytes (+0.39%) +25 bytes
23277 bytes +100 bytes (+0.43%) +34 bytes
23275 bytes +98 bytes (+0.42%) +32 bytes
23295 bytes +118 bytes (+0.51%) +52 bytes
23317 bytes +140 bytes (+0.60%) +74 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 - but your browser doesn't support it.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 19446 bytes -3731 bytes (-16.10%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 20104 bytes -3073 bytes (-13.26%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 20928 bytes -2249 bytes (-9.70%)
Brotli (Wikipedia) brotli brotli -q 11 21665 bytes -1512 bytes (-6.52%)
LZMA2 (Wikipedia) xz xz -9 22188 bytes -989 bytes (-4.27%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 22468 bytes -709 bytes (-3.06%)
Zstandard (Wikipedia) zstd zstd -19 23038 bytes -139 bytes (-0.60%)

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