Choose a version:
46% The original file has 315558 bytes (308.2k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 144718 bytes (141.3k, 46%).

After GZIP compression these minified files vary in size:
Boot
  57319 bytes (56.0k)
CDN, direct link
Baidu
  50284 bytes (49.1k)
CDN, direct link
cdnjs
  50272 bytes (49.1k)
CDN, direct link
unpkg
  49891 bytes (48.7k)
CDN, direct link
gzip -6 (default)
  49861 bytes (48.7k)
local copy
cdnhttps
  49846 bytes (48.7k)
CDN, direct link
gzip -9
  49693 bytes (48.5k)
local copy
libdeflate -12
  48084 bytes (47.0k)
local copy
7zip -mx=9 -tgzip
  48032 bytes (46.9k)
local copy
pigz -11 -n
  47850 bytes (46.7k)
local copy
kzip -s0 -rn -b5
  47838 bytes (46.7k)
local copy
Zopfli
  47708 bytes (46.6k)
local copy
Zopfli (defluff)
  47704 bytes (46.6k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-3.3.6.min.js

You will automatically get the smallest D3 3.3.6 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 2138 bytes by using my D3 3.3.6 Zopfli version instead of the best available CDN (4.48% smaller than cdnhttps, 47708 vs. 49846 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 --mls256 --bsr30 --lazy --ohh

(found December 21, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 256  --mls256
block splitting recursion 30  --bsr30
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 4 more bytes (47704 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/v3.3.6/d3.min.js --location | md5sum
a78cb1828eec044b0239e04930ed2b9e  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.3.6.min.zopfli.js.gz | md5sum
a78cb1828eec044b0239e04930ed2b9e  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.3.6/d3.min.js --location | sha1sum
cb0303b0771faa6cbd07b923fea1a18879f1b4cd  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.3.6.min.zopfli.js.gz | sha1sum
cb0303b0771faa6cbd07b923fea1a18879f1b4cd  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 57319 bytes a78cb1828eec044b0239e04930ed2b9e (invalid)
cdnjs 50272 bytes a78cb1828eec044b0239e04930ed2b9e (invalid)
unpkg 49891 bytes a78cb1828eec044b0239e04930ed2b9e July 11, 2016 @ 16:31
cdnhttps 49846 bytes a78cb1828eec044b0239e04930ed2b9e December 24, 2015 @ 07:33

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 50284 bytes 5d9e0087f4d64bc002fe1e455615e3a1 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
47708 bytes -3 bytes zopfli --i100000 --mls256 --bsr30 --lazy --ohh December 21, 2015 @ 18:46
47711 bytes -5 bytes zopfli --i10000 --mls256 --bsr30 --lazy --ohh November 23, 2015 @ 17:48
47716 bytes -2 bytes zopfli --i10000 --mls256 --bsr40 --lazy --ohh October 14, 2015 @ 02:41
47718 bytes -1 byte zopfli --i1000 --mls256 --bsr30 --lazy --ohh September 24, 2015 @ 20:08
47719 bytes -3 bytes zopfli --i10000 --mls256 --bsr25 --lazy --ohh September 23, 2015 @ 20:20
47722 bytes -3 bytes zopfli --i1000 --mls256 --bsr25 --lazy --ohh September 23, 2015 @ 07:38
47725 bytes -3 bytes zopfli --i1000 --mls256 --bsr14 --lazy --ohh September 19, 2015 @ 20:11
47728 bytes -16 bytes zopfli --i1000 --mls256 --bsr15 --lazy --ohh September 19, 2015 @ 20:08
47744 bytes -1 byte zopfli --i1000 --mls64 --bsr20 --lazy --ohh September 19, 2015 @ 20:03
47745 bytes zopfli --i100 --mls256 --bsr14 --lazy --ohh September 18, 2015 @ 20:13

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

Most recent activity on February 27, 2017 @ 10:17.

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
47843 47844 47900 47942 47943 47884 47860 47888 47900 47908 47864 48021 48022 47865 48009
47730 47763 47851 47769 47830 47777 47803 47824 47766 47878 47802 47798 48014 47859 48007
47749 47766 47823 47807 47782 47803 47809 47788 47821 47760 47777 47768 48008 47763 47855
47798 47753 47793 47815 47790 47759 47758 47731 47763 47759 47773 47759 47988 47758 47855
47756 47793 47800 47753 47816 47771 47766 47789 47799 47864 47865 47857 48003 47854 47863
47771 47733 47825 47744 47828 47743 47837 47742 47765 47768 47780 47771 48003 47832 47852
47755 47779 47788 47780 47802 47761 47845 47734 47749 47760 47777 47771 48007 47757 47858
47791 47729 47796 47821 47767 47740 47783 47822 47745 47768 47771 47767 48014 47756 47847
47783 47781 47851 47809 47751 47755 47800 47803 47761 47762 47773 47766 47991 47764 47840
47767 47801 47822 47802 47801 47805 47781 47786 47758 47853 47772 47765 47989 47745 47855
47773 47758 47826 47755 47802 47743 47781 47719 47764 47764 47781 47769 47996 47747 47844
47757 47748 47803 47815 47814 47760 47804 47724 47791 47758 47774 47762 48011 47760 47848
47803 47758 47783 47748 47826 47746 47819 47787 47740 47760 47774 47763 47992 47762 47847
47788 47800 47796 47741 47762 47792 47805 47826 47824 47738 47774 47765 47997 48013 47835
47797 47817 47755 47805 47802 47743 47822 47726 47739 47766 47773 47762 48013 47742 47850
47795 47774 47825 47810 47802 47792 47809 47723 47765 47765 47774 47767 47991 47804 47841
47841 47830 47760 47818 47838 47738 47779 47730 47783 47749 47774 47773 47988 47762 47843
47799 47736 47740 47822 47736 47803 47776 47746 47751 47767 47777 47766 47987 47755 47844
47797 47782 47792 47809 47815 47742 47821 47750 47743 47766 47766 47761 47992 47745 47855
47742 47792 47821 47809 47796 47800 47776 47728 47772 47776 47776 47764 48002 47748 47848
47799 47749 47796 47807 47789 47774 47789 47719 47734 47841 47774 47759 48008 47853 47841
47793 47757 47820 47803 47801 47743 47804 47708 47765 47734 47775 47757 48013 47740 47846
47760 47774 47789 47803 47801 47802 47806 47710 47735 47770 47795 47767 48003 47759 47851

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 47738 bytes 100%
1,000 47718 bytes -20 bytes 100%
10,000 47711 bytes -7 bytes 100%
100,000 47708 bytes -3 bytes 0.58%
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
47964 bytes +256 bytes (+0.54%) +126 bytes
48046 bytes +338 bytes (+0.71%) +208 bytes
48048 bytes +340 bytes (+0.71%) +210 bytes
47963 bytes +255 bytes (+0.53%) +125 bytes
47972 bytes +264 bytes (+0.55%) +134 bytes
47838 bytes +130 bytes (+0.27%)
47859 bytes +151 bytes (+0.32%) +21 bytes
47848 bytes +140 bytes (+0.29%) +10 bytes
47855 bytes +147 bytes (+0.31%) +17 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 38304 bytes -9404 bytes (-19.71%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 40519 bytes -7189 bytes (-15.07%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 41220 bytes -6488 bytes (-13.60%)
Brotli (Wikipedia) brotli brotli -q 11 43211 bytes -4497 bytes (-9.43%)
LZMA2 (Wikipedia) xz xz -9 43944 bytes -3764 bytes (-7.89%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 45737 bytes -1971 bytes (-4.13%)
ZSTD (Wikipedia) zstd zstd -19 46259 bytes -1449 bytes (-3.04%)

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