Choose a version:
45% The original file has 470070 bytes (459.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 211119 bytes (206.2k, 45%).

After GZIP compression these minified files vary in size:
Boot
  80403 bytes (78.5k)
CDN
cdnjs
  70634 bytes (69.0k)
CDN
cdnhttps
  70409 bytes (68.8k)
CDN
gzip -6 (default)
  70056 bytes (68.4k)
local copy
gzip -9
  69842 bytes (68.2k)
local copy
libdeflate -12
  67230 bytes (65.7k)
local copy
7zip -mx=9 -tgzip
  66820 bytes (65.3k)
local copy
kzip -s0 -rn -b6
  66472 bytes (64.9k)
local copy
pigz -11 -n
  66410 bytes (64.9k)
local copy
Zopfli
  66307 bytes (64.8k)
local copy
Zopfli (defluff)
  66306 bytes (64.8k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-4.1.1.min.js

You will automatically get the smallest D3 4.1.1 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 4102 bytes by using my D3 4.1.1 Zopfli version instead of the best available CDN (6.19% smaller than cdnhttps, 66307 vs. 70409 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 July 13, 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

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 (66306 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v4.1.1/d3.zip --location | md5sum
129b195a432d7c87310cede803863361  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-4.1.1.min.zopfli.js.gz | md5sum
129b195a432d7c87310cede803863361  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v4.1.1/d3.zip --location | sha1sum
d765993b7954209cfadaee5cd9755a05b54fa3ff  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-4.1.1.min.zopfli.js.gz | sha1sum
d765993b7954209cfadaee5cd9755a05b54fa3ff  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 80403 bytes 129b195a432d7c87310cede803863361 July 11, 2016 @ 07:50
cdnjs 70634 bytes 129b195a432d7c87310cede803863361 July 11, 2016 @ 05:01
cdnhttps 70409 bytes 129b195a432d7c87310cede803863361 November 22, 2016 @ 16:32

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

Other Versions

Available D3 versions at minime.stephan-brumme.com:

5.1.0, 5.0.1, 5.0.0,
4.13.0, 4.12.2, 4.12.1, 4.12.0, 4.11.0, 4.10.2, 4.10.1, 4.10.0,
4.9.1, 4.9.0, 4.8.0, 4.7.4, 4.7.3, 4.7.2, 4.7.1, 4.7.0, 4.6.0, 4.5.0, 4.4.4, 4.4.3, 4.4.2, 4.4.1, 4.4.0, 4.3.0, 4.2.8, 4.2.7, 4.2.6, 4.2.5, 4.2.4, 4.2.3, 4.2.2, 4.2.1, 4.2.0, 4.1.1, 4.1.0, 4.0.0,
3.5.17, 3.5.16, 3.5.15, 3.5.14, 3.5.13, 3.5.12, 3.5.11, 3.5.10, 3.5.9, 3.5.8, 3.5.7, 3.5.6, 3.5.5, 3.5.4, 3.5.3, 3.5.2, 3.5.1, 3.5.0, 3.4.13, 3.4.12, 3.4.11, 3.4.10, 3.4.9, 3.4.8, 3.4.6, 3.4.5, 3.4.4, 3.4.3, 3.4.2, 3.4.1, 3.4.0, 3.3.13, 3.3.12, 3.3.11, 3.3.10, 3.3.9, 3.3.8, 3.3.7, 3.3.6, 3.3.5, 3.3.4, 3.3.3, 3.3.2, 3.3.1, 3.3.0, 3.2.8, 3.2.7, 3.2.6, 3.2.5, 3.2.4, 3.2.3, 3.2.2, 3.2.1, 3.2.0, 3.1.10, 3.1.9, 3.1.8, 3.1.7, 3.1.6, 3.1.5, 3.1.4, 3.1.3, 3.1.2, 3.1.1, 3.1.0, 3.0.8, 3.0.7, 3.0.6, 3.0.5, 3.0.4, 3.0.3, 3.0.2, 3.0.1, 3.0.0

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

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
66307 bytes -1 byte zopfli --i1000000 --mls2048 --bsr23 --lazy --ohh July 13, 2016 @ 03:46
66308 bytes -1 byte zopfli --i100000 --mls2048 --bsr23 --lazy --ohh July 12, 2016 @ 18:01
66309 bytes -6 bytes zopfli --i100000 --mls2048 --bsr13 --lazy --ohh July 11, 2016 @ 19:36
66315 bytes -7 bytes zopfli --i10000 --mls2048 --bsr13 --lazy --ohh July 11, 2016 @ 18:13
66322 bytes -1 byte zopfli --i1000 --mls2048 --bsr13 --lazy --ohh July 11, 2016 @ 18:00
66323 bytes -15 bytes zopfli --i1000 --mls2048 --bsr17 --lazy --ohh July 11, 2016 @ 17:58
66338 bytes -13 bytes zopfli --i1000 --mls32 --bsr6 --lazy --ohh July 11, 2016 @ 17:57
66351 bytes zopfli --i100 --mls1024 --bsr13 --lazy --ohh July 11, 2016 @ 17:48

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 @ 16:32.

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
66650 66652 66536 66490 66543 66540 66536 66535 66461 66424 66542 66530 66663 66563 66631
66440 66438 66465 66463 66444 66445 66444 66453 66329 66362 66453 66411 66518 66399 66419
66550 66581 66512 66516 66331 66503 66429 66434 66394 66344 66315 66354 66442 66454 66442
66517 66508 66519 66435 66434 66518 66434 66371 66434 66381 66319 66343 66471 66465 66491
67037 66534 66540 66513 66524 66522 66419 66434 66439 66337 66325 66339 66462 66393 66394
67030 66506 67026 67015 66435 66412 66423 66435 66334 66336 66334 66336 66371 66393 66456
67049 66426 66430 66428 66433 66418 66420 66431 66440 66340 66321 66344 66491 66451 66443
66514 66510 66505 67017 66429 66413 66364 66431 66442 66333 66315 66345 66492 66373 66467
66516 66513 66315 66507 66434 66502 66429 66433 66330 66331 66317 66339 66461 66460 66488
66504 66513 66520 66498 66508 66429 66428 66430 66333 66326 66309 66333 66487 66462 66490
66521 66526 66525 66511 66518 66508 66429 66390 66336 66329 66332 66382 66468 66408 66500
66401 66521 66439 66434 66516 66511 66423 66451 66439 66336 66318 66339 66468 66463 66464
66523 66504 66505 66501 66430 66502 66417 66434 66334 66358 66408 66378 66486 66368 66438
66527 67011 67013 66499 66437 66500 66359 66328 66434 66332 66316 66343 66465 66468 66441
67009 67010 67009 66515 66435 66422 66422 66429 66347 66341 66317 66336 66488 66460 66468
66521 66501 67021 67018 66435 66419 66417 66437 66441 66334 66317 66340 66487 66443 66444
66520 66502 66517 66504 66433 66504 66422 66327 66333 66338 66309 66340 66493 66471 66469
66514 66514 66517 66514 66432 66415 66419 66441 66438 66357 66319 66340 66466 66456 66439
67013 67003 66511 67017 66434 66493 66416 66434 66334 66327 66321 66352 66489 66462 66437
66513 66514 66507 67008 66430 66425 66430 66437 66331 66347 66307 66351 66464 66467 66447
66512 66502 66518 66515 66431 66499 66415 66334 66335 66330 66328 66333 66488 66467 66464
66531 66534 66524 66534 66373 66366 66362 66369 66338 66346 66324 66349 66466 66471 66463
66543 66500 67026 66516 67020 67018 66426 66432 66338 66332 66319 66351 66377 66368 66489

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 66351 bytes 100%
1,000 66320 bytes -31 bytes 100%
10,000 66314 bytes -6 bytes 100%
100,000 66308 bytes -6 bytes 0.87%
1,000,000 66307 bytes -1 byte 0.29%
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
66485 bytes +178 bytes (+0.27%) +13 bytes
67993 bytes +1686 bytes (+2.54%) +1521 bytes
67486 bytes +1179 bytes (+1.78%) +1014 bytes
67095 bytes +788 bytes (+1.19%) +623 bytes
66594 bytes +287 bytes (+0.43%) +122 bytes
66594 bytes +287 bytes (+0.43%) +122 bytes
66472 bytes +165 bytes (+0.25%)
66492 bytes +185 bytes (+0.28%) +20 bytes
66513 bytes +206 bytes (+0.31%) +41 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 52625 bytes -13682 bytes (-20.63%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 59002 bytes -7305 bytes (-11.02%)
LZMA2 (Wikipedia) xz xz -9 59484 bytes -6823 bytes (-10.29%)
Brotli (Wikipedia) brotli brotli -q 11 59796 bytes -6511 bytes (-9.82%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 60494 bytes -5813 bytes (-8.77%)
ZSTD (Wikipedia) zstd zstd -19 64786 bytes -1521 bytes (-2.29%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 66353 bytes +46 bytes (+0.07%)

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