Choose a version:
47% The original file has 267937 bytes (261.7k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 126781 bytes (123.8k, 47%).

After GZIP compression these minified files vary in size:
Boot
  48721 bytes (47.6k)
CDN, direct link
Baidu
  42630 bytes (41.6k)
CDN, direct link
cdnjs
  42624 bytes (41.6k)
CDN, direct link
gzip -6 (default)
  42296 bytes (41.3k)
local copy
cdnhttps
  42280 bytes (41.3k)
CDN, direct link
unpkg
  42270 bytes (41.3k)
CDN, direct link
jsdelivr
  42206 bytes (41.2k)
CDN, direct link
gzip -9
  42181 bytes (41.2k)
local copy
7zip -mx=9 -tgzip
  40788 bytes (39.8k)
local copy
libdeflate -12
  40757 bytes (39.8k)
local copy
pigz -11 -n
  40730 bytes (39.8k)
local copy
kzip -s0 -rn -b8
  40641 bytes (39.7k)
local copy
Zopfli
  40494 bytes (39.5k)
local copy
Zopfli (defluff)
  40491 bytes (39.5k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-3.0.4.min.js

You will automatically get the smallest D3 3.0.4 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 1712 bytes by using my D3 3.0.4 Zopfli version instead of the best available CDN (4.23% smaller than jsdelivr, 40494 vs. 42206 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 --i100000 --mb8 --mls2048 --bsr16 --lazy --ohh

(found November 23, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 2048  --mls2048
block splitting recursion 16  --bsr16
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 3 more bytes (40491 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/v3.0.4/d3.min.js --location | md5sum
7ae8374847e3106ecab25e44afb4d1fd  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.0.4.min.zopfli.js.gz | md5sum
7ae8374847e3106ecab25e44afb4d1fd  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.0.4/d3.min.js --location | sha1sum
f3ace08c0e23638e461ff8ff6460177b6e619187  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.0.4.min.zopfli.js.gz | sha1sum
f3ace08c0e23638e461ff8ff6460177b6e619187  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 48721 bytes 7ae8374847e3106ecab25e44afb4d1fd (invalid)
cdnjs 42624 bytes 7ae8374847e3106ecab25e44afb4d1fd (invalid)
cdnhttps 42280 bytes 7ae8374847e3106ecab25e44afb4d1fd December 24, 2015 @ 07:33
unpkg 42270 bytes 7ae8374847e3106ecab25e44afb4d1fd July 11, 2016 @ 16:32

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 42630 bytes eabf2fd2f69de28b418de95bf39081b0 only whitespaces differ (invalid)
jsdelivr 42206 bytes eabf2fd2f69de28b418de95bf39081b0 only whitespaces differ (invalid)

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

Other Versions

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

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
40494 bytes -6 bytes zopfli --i100000 --mls2048 --bsr16 --lazy --ohh November 23, 2015 @ 17:01
40500 bytes -5 bytes zopfli --i10000 --mls2048 --bsr16 --lazy --ohh November 23, 2015 @ 16:00
40505 bytes -8 bytes zopfli --i1000 --mls2048 --bsr16 --lazy --ohh September 20, 2015 @ 19:36
40513 bytes -1 byte zopfli --i1000 --mls64 --bsr14 --lazy --ohh September 20, 2015 @ 19:19
40514 bytes -8 bytes zopfli --i1000 --mls64 --bsr6 --lazy --ohh September 20, 2015 @ 19:15
40522 bytes zopfli --i100 --mls2048 --bsr16 --lazy --ohh September 18, 2015 @ 20:34

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

Most recent activity on March 5, 2017 @ 04:35.

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 or 100,000.
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
40623 40638 40636 40689 40635 40635 40645 40687 40640 40711 40712 40632 40713 40684 40723
40686 40697 40696 40564 40693 40692 40690 40676 40675 40712 40714 40644 40716 40620 40696
40536 40540 40560 40537 40567 40511 40680 40681 40681 40713 40713 40616 40719 40553 40722
40697 40597 40559 40607 40549 40532 40681 40555 40679 40579 40711 40558 40716 40582 40584
40690 40590 40596 40591 40678 40542 40549 40536 40570 40534 40519 40585 40712 40565 40714
40686 40615 40681 40534 40573 40609 40542 40679 40593 40704 40582 40702 40711 40619 40692
40558 40560 40542 40607 40543 40563 40570 40556 40561 40567 40570 40587 40717 40617 40691
40562 40547 40557 40544 40686 40540 40622 40577 40575 40712 40540 40596 40711 40621 40721
40596 40559 40524 40514 40568 40523 40586 40582 40574 40535 40529 40572 40711 40584 40699
40525 40572 40572 40539 40561 40557 40580 40588 40536 40712 40704 40584 40711 40716 40692
40555 40561 40548 40552 40563 40509 40581 40531 40572 40529 40568 40583 40583 40612 40717
40561 40565 40601 40563 40545 40553 40565 40567 40591 40712 40713 40588 40710 40582 40724
40529 40557 40689 40558 40543 40546 40569 40592 40698 40522 40494 40581 40665 40615 40712
40686 40556 40574 40538 40526 40546 40583 40691 40566 40698 40697 40578 40711 40582 40697
40564 40697 40562 40550 40549 40561 40592 40582 40565 40572 40580 40586 40581 40584 40589
40563 40561 40552 40539 40628 40521 40634 40559 40565 40697 40697 40555 40718 40592 40582
40688 40628 40556 40692 40534 40547 40581 40579 40600 40712 40705 40594 40711 40576 40712
40564 40591 40545 40539 40532 40543 40532 40535 40573 40530 40579 40581 40713 40622 40600
40684 40674 40674 40538 40687 40547 40580 40587 40529 40712 40582 40583 40710 40628 40591
40589 40539 40541 40548 40575 40541 40589 40590 40535 40712 40581 40587 40711 40583 40718
40556 40540 40547 40546 40570 40532 40579 40570 40558 40711 40530 40592 40710 40583 40717
40576 40561 40583 40539 40538 40516 40558 40532 40574 40520 40582 40586 40710 40615 40691
40686 40537 40543 40515 40573 40589 40599 40571 40699 40712 40705 40574 40710 40614 40596

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 40522 bytes 100%
1,000 40505 bytes -17 bytes 100%
10,000 40500 bytes -5 bytes 100%
100,000 40494 bytes -6 bytes 0.29%
1,000,000
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
40725 bytes +231 bytes (+0.57%) +84 bytes
40739 bytes +245 bytes (+0.61%) +98 bytes
40723 bytes +229 bytes (+0.57%) +82 bytes
40740 bytes +246 bytes (+0.61%) +99 bytes
40738 bytes +244 bytes (+0.60%) +97 bytes
40759 bytes +265 bytes (+0.65%) +118 bytes
40750 bytes +256 bytes (+0.63%) +109 bytes
40736 bytes +242 bytes (+0.60%) +95 bytes
40641 bytes +147 bytes (+0.36%)

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 32828 bytes -7666 bytes (-18.93%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 34627 bytes -5867 bytes (-14.49%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 36126 bytes -4368 bytes (-10.79%)
Brotli (Wikipedia) brotli brotli -q 11 36861 bytes -3633 bytes (-8.97%)
LZMA2 (Wikipedia) xz xz -9 37636 bytes -2858 bytes (-7.06%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 39205 bytes -1289 bytes (-3.18%)
ZSTD (Wikipedia) zstd zstd -19 39281 bytes -1213 bytes (-3.00%)

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 2017.
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