Choose a version:
48% The original file has 511371 bytes (499.4k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 246120 bytes (240.4k, 48%).

After GZIP compression these minified files vary in size:
Boot
  81400 bytes (79.5k)
CDN
cdnjs
  81400 bytes (79.5k)
CDN
gzip -6 (default)
  80737 bytes (78.8k)
local copy
gzip -9
  80422 bytes (78.5k)
local copy
libdeflate -12
  77235 bytes (75.4k)
local copy
7zip -mx=9 -tgzip
  76722 bytes (74.9k)
local copy
kzip -s0 -rn -b8
  76387 bytes (74.6k)
local copy
pigz -11 -n
  76292 bytes (74.5k)
local copy
Zopfli
  76228 bytes (74.4k)
local copy
Zopfli (defluff)
  76226 bytes (74.4k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-5.12.0.min.js (or via HTTPS)

You will automatically get the smallest D3 5.12.0 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 5172 bytes by using my D3 5.12.0 Zopfli version instead of the best available CDN (6.78% smaller than cdnjs, 76228 vs. 81400 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 --mls2 --bsr17 --lazy --ohh

(found September 12, 2019)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 2  --mls2
block splitting recursion 17  --bsr17
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 (76226 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/v5.12.0/d3.zip --location | md5sum
82cf43358c1d5de3b328f77464ef3d42  -
curl --silent --compressed https://minime.stephan-brumme.com/files/d3/d3-5.12.0.min.zopfli.js.gz | md5sum
82cf43358c1d5de3b328f77464ef3d42  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v5.12.0/d3.zip --location | sha1sum
52496f468b33b778dd975e9986161df1c6f68ced  -
curl --silent --compressed https://minime.stephan-brumme.com/files/d3/d3-5.12.0.min.zopfli.js.gz | sha1sum
52496f468b33b778dd975e9986161df1c6f68ced  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 81400 bytes 82cf43358c1d5de3b328f77464ef3d42 September 7, 2019 @ 06:46
cdnjs 81400 bytes 82cf43358c1d5de3b328f77464ef3d42 September 7, 2019 @ 06:46

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

Other Versions

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

5.12.0, 5.11.0, 5.10.1, 5.10.0,
5.9.7, 5.9.6, 5.9.5, 5.9.4, 5.9.3, 5.9.2, 5.9.1, 5.9.0, 5.8.2, 5.8.1, 5.8.0, 5.7.0, 5.6.0, 5.5.0, 5.4.0, 5.3.0, 5.2.0, 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
76228 bytes -2 bytes zopfli --i1000000 --mls2 --bsr17 --lazy --ohh September 12, 2019 @ 20:51
76230 bytes -4 bytes zopfli --i1000000 --mls4096 --bsr14 --lazy --ohh September 12, 2019 @ 20:51
76234 bytes -1 byte zopfli --i100000 --mls2 --bsr17 --lazy --ohh September 11, 2019 @ 20:59
76235 bytes -5 bytes zopfli --i100000 --mls4096 --bsr20 --lazy --ohh September 11, 2019 @ 19:32
76240 bytes -10 bytes zopfli --i10000 --mls4096 --bsr20 --lazy --ohh September 11, 2019 @ 17:35
76250 bytes -3 bytes zopfli --i1000 --mls4096 --bsr17 --lazy --ohh September 11, 2019 @ 16:37
76253 bytes -1 byte zopfli --i1000 --mls4096 --bsr20 --lazy --ohh September 11, 2019 @ 16:37
76254 bytes -15 bytes zopfli --i1000 --mls2048 --bsr20 --lazy --ohh September 11, 2019 @ 16:37
76269 bytes zopfli --i100 --mls4096 --bsr17 --lazy --ohh September 11, 2019 @ 16:32

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

Most recent activity on September 13, 2019 @ 10:56.

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
76661 76598 76658 76652 76651 76654 76662 76792 76780 76796 76790 76511 76565 76593 76865
76314 76471 76317 76306 76495 76307 76307 76316 76451 76561 76281 76248 76490 76474 76400
76549 76533 76469 76452 76253 76300 76262 76260 76259 76272 76253 76273 76440 76434 76390
76651 76556 76522 76441 76546 76289 76307 76262 76460 76266 76265 76257 76432 76382 76698
76260 76273 76307 76302 76535 76300 76299 76292 76533 76322 76365 76405 76421 76482 76507
76433 76470 76467 76442 76254 76264 76262 76259 76477 76644 76241 76255 76458 76479 76642
76248 76256 76468 76443 76251 76281 76272 76254 76465 76266 76245 76265 76266 76439 76748
76584 76476 76583 76449 76254 76294 76271 76262 76433 76623 76255 76256 76407 76406 76651
76465 76467 76467 76452 76249 76282 76263 76258 76460 76265 76252 76425 76432 76499 76477
76562 76464 76463 76250 76258 76284 76263 76256 76465 76263 76250 76235 76409 76478 76493
76438 76462 76469 76449 76547 76589 76267 76263 76461 76474 76242 76230 76437 76490 76653
76457 76465 76256 76245 76255 76279 76264 76255 76460 76264 76265 76251 76432 76471 76570
76439 76464 76464 76443 76450 76275 76264 76256 76457 76485 76243 76242 76423 76500 76470
76228 76460 76257 76302 76250 76266 76299 76258 76534 76272 76246 76242 76416 76479 76476
76580 76462 76468 76451 76251 76262 76272 76257 76463 76266 76242 76246 76396 76509 76641
76454 76463 76465 76531 76250 76258 76264 76255 76462 76269 76244 76249 76244 76505 76643
76583 76464 76462 76448 76251 76260 76263 76258 76467 76290 76242 76235 76406 76477 76533
76456 76470 76470 76450 76250 76276 76267 76257 76463 76266 76248 76243 76430 76489 76533
76586 76586 76467 76561 76544 76567 76261 76260 76457 76272 76249 76256 76473 76487 76475
76454 76465 76262 76249 76252 76267 76264 76256 76461 76268 76251 76243 76435 76488 76570
76455 76468 76461 76449 76257 76276 76268 76256 76459 76268 76249 76243 76430 76506 76602
76444 76465 76472 76445 76249 76277 76261 76254 76459 76268 76241 76248 76408 76317 76598
76553 76467 76472 76448 76255 76276 76263 76259 76460 76265 76263 76253 76404 76452 76473

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 76269 bytes 100%
1,000 76250 bytes -19 bytes 100%
10,000 76240 bytes -10 bytes 100%
100,000 76234 bytes -6 bytes 1.16%
1,000,000 76228 bytes -6 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
76671 bytes +443 bytes (+0.58%) +284 bytes
78041 bytes +1813 bytes (+2.38%) +1654 bytes
77920 bytes +1692 bytes (+2.22%) +1533 bytes
76668 bytes +440 bytes (+0.58%) +281 bytes
76664 bytes +436 bytes (+0.57%) +277 bytes
76662 bytes +434 bytes (+0.57%) +275 bytes
76624 bytes +396 bytes (+0.52%) +237 bytes
76443 bytes +215 bytes (+0.28%) +56 bytes
76387 bytes +159 bytes (+0.21%)

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 60000 bytes -16228 bytes (-21.29%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 66750 bytes -9478 bytes (-12.43%)
LZMA2 (Wikipedia) xz xz -9 67712 bytes -8516 bytes (-11.17%)
Brotli (Wikipedia) brotli brotli -q 11 67813 bytes -8415 bytes (-11.04%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 69815 bytes -6413 bytes (-8.41%)
Zstandard (Wikipedia) zstd zstd -19 73123 bytes -3105 bytes (-4.07%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 75811 bytes -417 bytes (-0.55%)

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 2019.
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