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
  40786 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
  40643 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/d3-3.0.5.min.js

You will automatically get the smallest D3 3.0.5 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 3.0.5 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/v3.0.5/d3.min.js --location | md5sum
438826e9b5847ea8dcb67d86aa39d5cb  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.0.5.min.zopfli.js.gz | md5sum
438826e9b5847ea8dcb67d86aa39d5cb  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.0.5/d3.min.js --location | sha1sum
d33954109b17028e59c5f0423b6d5edce0ba85f8  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.0.5.min.zopfli.js.gz | sha1sum
d33954109b17028e59c5f0423b6d5edce0ba85f8  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 48721 bytes 438826e9b5847ea8dcb67d86aa39d5cb (invalid)
cdnjs 42624 bytes 438826e9b5847ea8dcb67d86aa39d5cb (invalid)
cdnhttps 42280 bytes 438826e9b5847ea8dcb67d86aa39d5cb December 24, 2015 @ 07:33
unpkg 42270 bytes 438826e9b5847ea8dcb67d86aa39d5cb July 11, 2016 @ 16:32

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 42630 bytes d7d30603c24be2da91f21d065de3ea31 only whitespaces differ (invalid)
jsdelivr 42206 bytes d7d30603c24be2da91f21d065de3ea31 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 @ 17:02
40500 bytes -5 bytes zopfli --i10000 --mls2048 --bsr16 --lazy --ohh November 23, 2015 @ 16:02
40505 bytes -6 bytes zopfli --i1000 --mls2048 --bsr16 --lazy --ohh September 20, 2015 @ 18:51
40511 bytes -2 bytes zopfli --i1000 --mls64 --bsr12 --lazy --ohh September 20, 2015 @ 18:33
40513 bytes -9 bytes zopfli --i1000 --mls64 --bsr6 --lazy --ohh September 20, 2015 @ 18:31
40522 bytes zopfli --i100 --mls2048 --bsr16 --lazy --ohh September 18, 2015 @ 22:08

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 @ 04:15.

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
40622 40638 40634 40689 40634 40635 40645 40687 40639 40713 40712 40633 40713 40683 40722
40685 40699 40696 40564 40695 40692 40690 40676 40676 40711 40714 40645 40716 40620 40697
40536 40541 40560 40536 40567 40511 40681 40681 40512 40713 40713 40616 40719 40555 40723
40697 40597 40560 40615 40549 40529 40682 40555 40679 40579 40712 40558 40718 40584 40584
40690 40590 40597 40590 40678 40543 40551 40537 40570 40535 40519 40585 40712 40578 40714
40686 40615 40680 40535 40573 40611 40544 40679 40593 40704 40582 40702 40712 40619 40692
40558 40560 40559 40607 40543 40564 40570 40556 40561 40567 40571 40587 40717 40618 40588
40561 40548 40557 40545 40688 40540 40542 40578 40575 40712 40541 40597 40711 40702 40721
40597 40560 40609 40518 40568 40509 40585 40582 40574 40536 40529 40572 40711 40585 40720
40525 40572 40676 40539 40548 40557 40581 40588 40536 40713 40704 40584 40711 40714 40692
40556 40561 40576 40554 40522 40509 40581 40531 40573 40530 40568 40583 40583 40611 40717
40561 40566 40602 40543 40545 40554 40565 40568 40591 40712 40713 40588 40698 40584 40724
40529 40557 40689 40559 40544 40546 40569 40592 40697 40522 40494 40581 40728 40615 40712
40687 40558 40575 40539 40528 40546 40583 40692 40566 40699 40697 40577 40711 40582 40697
40564 40698 40562 40551 40549 40561 40592 40582 40566 40573 40581 40587 40580 40585 40588
40562 40563 40547 40538 40629 40521 40634 40558 40566 40696 40697 40556 40697 40592 40582
40690 40628 40557 40692 40534 40548 40581 40579 40706 40712 40706 40594 40721 40582 40712
40564 40589 40557 40540 40533 40543 40532 40535 40574 40530 40579 40581 40713 40621 40599
40685 40675 40558 40539 40687 40550 40580 40587 40530 40712 40583 40583 40713 40628 40591
40588 40539 40539 40548 40575 40541 40590 40590 40535 40712 40582 40588 40712 40584 40718
40557 40542 40580 40525 40570 40533 40580 40571 40559 40712 40530 40706 40696 40583 40717
40576 40561 40575 40538 40538 40516 40558 40532 40574 40521 40582 40587 40696 40615 40580
40685 40538 40543 40515 40575 40589 40600 40570 40699 40711 40705 40697 40713 40615 40597

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
40726 bytes +232 bytes (+0.57%) +83 bytes
40741 bytes +247 bytes (+0.61%) +98 bytes
40723 bytes +229 bytes (+0.57%) +80 bytes
40742 bytes +248 bytes (+0.61%) +99 bytes
40738 bytes +244 bytes (+0.60%) +95 bytes
40763 bytes +269 bytes (+0.66%) +120 bytes
40750 bytes +256 bytes (+0.63%) +107 bytes
40734 bytes +240 bytes (+0.59%) +91 bytes
40643 bytes +149 bytes (+0.37%)

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 34621 bytes -5873 bytes (-14.50%)
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 39204 bytes -1290 bytes (-3.19%)
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