Choose a version:
45% The original file has 337784 bytes (329.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 151665 bytes (148.1k, 45%).

After GZIP compression these minified files vary in size:
Boot
  61037 bytes (59.6k)
CDN
jsdelivr
  61037 bytes (59.6k)
CDN
cdnjs
  53630 bytes (52.4k)
CDN
unpkg
  53630 bytes (52.4k)
CDN
gzip -6 (default)
  53506 bytes (52.3k)
local copy
cdnhttps
  53496 bytes (52.2k)
CDN
gzip -9
  53368 bytes (52.1k)
local copy
libdeflate -12
  51665 bytes (50.5k)
local copy
7zip -mx=9 -tgzip
  51609 bytes (50.4k)
local copy
pigz -11 -n
  51359 bytes (50.2k)
local copy
kzip -s0 -rn -b8
  51317 bytes (50.1k)
local copy
Zopfli
  51267 bytes (50.1k)
local copy
Zopfli (defluff)
  51266 bytes (50.1k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-3.5.12.min.js (or via HTTPS)

You will automatically get the smallest D3 3.5.12 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 2229 bytes by using my D3 3.5.12 Zopfli version instead of the best available CDN (4.35% smaller than cdnhttps, 51267 vs. 53496 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 --mls128 --bsr7 --lazy --ohh

(found December 18, 2015)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 128  --mls128
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

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 (51266 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/v3.5.12/d3.min.js --location | md5sum
c243eee8bae247ff2e2e32fca9016c11  -
curl --silent --compressed https://minime.stephan-brumme.com/files/d3/d3-3.5.12.min.zopfli.js.gz | md5sum
c243eee8bae247ff2e2e32fca9016c11  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.5.12/d3.min.js --location | sha1sum
58f8b2aea4a928bdd6ace7e4abd5ddd0e7c9cb5c  -
curl --silent --compressed https://minime.stephan-brumme.com/files/d3/d3-3.5.12.min.zopfli.js.gz | sha1sum
58f8b2aea4a928bdd6ace7e4abd5ddd0e7c9cb5c  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 61037 bytes c243eee8bae247ff2e2e32fca9016c11 December 19, 2015 @ 06:22
jsdelivr 61037 bytes c243eee8bae247ff2e2e32fca9016c11 (invalid)
cdnjs 53630 bytes c243eee8bae247ff2e2e32fca9016c11 December 18, 2015 @ 09:01
unpkg 53630 bytes c243eee8bae247ff2e2e32fca9016c11 July 11, 2016 @ 16:30
cdnhttps 53496 bytes c243eee8bae247ff2e2e32fca9016c11 December 24, 2015 @ 07:33

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

Other Versions

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

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
51267 bytes -3 bytes zopfli --i1000000 --mls128 --bsr7 --lazy --ohh December 18, 2015 @ 21:14
51270 bytes -5 bytes zopfli --i100000 --mls128 --bsr7 --lazy --ohh December 18, 2015 @ 11:00
51275 bytes -1 byte zopfli --i10000 --mls128 --bsr7 --lazy --ohh December 18, 2015 @ 09:27
51276 bytes -4 bytes zopfli --i100000 --mls32768 --bsr9 --lazy --ohh December 18, 2015 @ 08:46
51280 bytes -8 bytes zopfli --i10000 --mls32768 --bsr9 --lazy --ohh December 18, 2015 @ 07:34
51288 bytes -7 bytes zopfli --i1000 --mls32768 --bsr9 --lazy --ohh December 18, 2015 @ 07:26
51295 bytes zopfli --i100 --mls32768 --bsr9 --lazy --ohh December 18, 2015 @ 07:15

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

Most recent activity on July 11, 2016 @ 16:30.

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
51418 51480 51432 51502 51416 51417 51451 51444 51443 51443 51528 51429 51416 51418 51550
51337 51308 51300 51331 51381 51346 51388 51404 51404 51397 51422 51404 51401 51404 51305
51327 51463 51335 51359 51339 51322 51328 51397 51390 51384 51403 51398 51378 51384 51308
51380 51436 51358 51470 51373 51391 51267 51402 51377 51395 51385 51407 51385 51385 51381
51362 51454 51333 51357 51462 51420 51354 51402 51394 51391 51408 51408 51538 51375 51543
51353 51457 51341 51374 51357 51405 51355 51404 51404 51401 51393 51408 51386 51378 51276
51376 51359 51361 51388 51339 51372 51361 51403 51383 51397 51531 51420 51385 51390 51308
51435 51430 51426 51363 51449 51448 51330 51401 51402 51397 51396 51386 51395 51385 51311
51320 51431 51361 51336 51304 51371 51458 51417 51387 51393 51399 51401 51384 51379 51327
51350 51353 51359 51377 51341 51320 51378 51413 51409 51393 51398 51407 51390 51386 51309
51367 51457 51454 51349 51318 51427 51352 51398 51395 51385 51395 51394 51392 51387 51377
51378 51429 51343 51381 51355 51386 51361 51397 51416 51388 51402 51392 51384 51376 51377
51457 51334 51359 51364 51356 51430 51329 51403 51378 51399 51390 51395 51390 51376 51302
51355 51370 51360 51329 51460 51370 51455 51406 51378 51384 51409 51410 51380 51384 51309
51374 51434 51345 51373 51357 51429 51353 51413 51387 51387 51397 51408 51397 51388 51333
51313 51317 51437 51378 51392 51427 51333 51404 51400 51398 51402 51403 51381 51375 51310
51382 51455 51337 51364 51355 51370 51465 51403 51397 51387 51410 51410 51382 51379 51327
51381 51332 51360 51349 51358 51370 51344 51405 51390 51389 51399 51408 51384 51376 51277
51373 51361 51365 51378 51321 51426 51351 51401 51399 51397 51403 51408 51386 51378 51307
51314 51419 51337 51378 51348 51343 51327 51404 51416 51381 51399 51385 51383 51386 51312
51328 51435 51361 51376 51396 51377 51352 51403 51397 51393 51402 51397 51386 51375 51326
51297 51363 51361 51377 51355 51347 51352 51402 51402 51397 51396 51408 51380 51378 51328
51409 51418 51427 51369 51323 51430 51325 51408 51377 51396 51380 51392 51384 51385 51350

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 51295 bytes 100%
1,000 51282 bytes -13 bytes 100%
10,000 51275 bytes -7 bytes 100%
100,000 51270 bytes -5 bytes 0.87%
1,000,000 51267 bytes -3 bytes 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
51576 bytes +309 bytes (+0.60%) +259 bytes
51576 bytes +309 bytes (+0.60%) +259 bytes
51583 bytes +316 bytes (+0.62%) +266 bytes
51518 bytes +251 bytes (+0.49%) +201 bytes
51461 bytes +194 bytes (+0.38%) +144 bytes
51458 bytes +191 bytes (+0.37%) +141 bytes
51353 bytes +86 bytes (+0.17%) +36 bytes
51372 bytes +105 bytes (+0.20%) +55 bytes
51317 bytes +50 bytes (+0.10%)

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 40888 bytes -10379 bytes (-20.24%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 43500 bytes -7767 bytes (-15.15%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 44568 bytes -6699 bytes (-13.07%)
Brotli (Wikipedia) brotli brotli -q 11 46288 bytes -4979 bytes (-9.71%)
LZMA2 (Wikipedia) xz xz -9 47004 bytes -4263 bytes (-8.32%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 48955 bytes -2312 bytes (-4.51%)
Zstandard (Wikipedia) zstd zstd -19 49555 bytes -1712 bytes (-3.34%)

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