Choose a version:
46% The original file has 315497 bytes (308.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 144801 bytes (141.4k, 46%).

After GZIP compression these minified files vary in size:
Boot
  57389 bytes (56.0k)
CDN, direct link
jsdelivr
  57389 bytes (56.0k)
CDN, direct link
Baidu
  50278 bytes (49.1k)
CDN, direct link
cdnjs
  50267 bytes (49.1k)
CDN, direct link
unpkg
  49888 bytes (48.7k)
CDN, direct link
gzip -6 (default)
  49868 bytes (48.7k)
local copy
cdnhttps
  49850 bytes (48.7k)
CDN, direct link
gzip -9
  49696 bytes (48.5k)
local copy
libdeflate -12
  48118 bytes (47.0k)
local copy
7zip -mx=9 -tgzip
  48028 bytes (46.9k)
local copy
pigz -11 -n
  47870 bytes (46.7k)
local copy
kzip -s0 -rn -b5
  47845 bytes (46.7k)
local copy
Zopfli
  47743 bytes (46.6k)
local copy
Zopfli (defluff)
  47742 bytes (46.6k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-3.3.3.min.js

You will automatically get the smallest D3 3.3.3 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 2107 bytes by using my D3 3.3.3 Zopfli version instead of the best available CDN (4.41% smaller than cdnhttps, 47743 vs. 49850 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 --mls64 --bsr15 --lazy --ohh

(found December 21, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 64  --mls64
block splitting recursion 15  --bsr15
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 (47742 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/v3.3.3/d3.min.js --location | md5sum
4632fd303c76931a86dd2f93c44cbfa2  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.3.3.min.zopfli.js.gz | md5sum
4632fd303c76931a86dd2f93c44cbfa2  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.3.3/d3.min.js --location | sha1sum
3a959320fdfd7ca7d24079c21390307e8b0d7439  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.3.3.min.zopfli.js.gz | sha1sum
3a959320fdfd7ca7d24079c21390307e8b0d7439  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 57389 bytes 4632fd303c76931a86dd2f93c44cbfa2 (invalid)
jsdelivr 57389 bytes 4632fd303c76931a86dd2f93c44cbfa2 (invalid)
cdnjs 50267 bytes 4632fd303c76931a86dd2f93c44cbfa2 (invalid)
unpkg 49888 bytes 4632fd303c76931a86dd2f93c44cbfa2 July 11, 2016 @ 16:31
cdnhttps 49850 bytes 4632fd303c76931a86dd2f93c44cbfa2 December 24, 2015 @ 07:33

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 50278 bytes 4ab241822679f348e221dbb4cf3f839f 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:

4.11.0, 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
47743 bytes -6 bytes zopfli --i100000 --mls64 --bsr15 --lazy --ohh December 21, 2015 @ 17:37
47749 bytes -1 byte zopfli --i10000 --mls64 --bsr15 --lazy --ohh November 23, 2015 @ 17:48
47750 bytes -4 bytes zopfli --i10000 --mls16384 --bsr15 --lazy --ohh October 14, 2015 @ 07:44
47754 bytes -5 bytes zopfli --i1000 --mls64 --bsr15 --lazy --ohh September 19, 2015 @ 22:29
47759 bytes -12 bytes zopfli --i1000 --mls32 --bsr11 --lazy --ohh September 19, 2015 @ 22:24
47771 bytes zopfli --i100 --mls64 --bsr15 --lazy --ohh September 18, 2015 @ 20:46

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 @ 04:52.

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
47892 47899 47854 47851 47865 47863 47912 47867 47919 47928 48029 48035 48021 47893 48024
47784 47831 47855 47763 47790 47774 47772 47911 47779 47785 47796 47847 48023 47799 47887
47800 47791 47781 47771 47772 47774 47815 47777 47783 47892 47793 47785 48020 47807 47878
47773 47785 47826 47828 47773 47769 47814 47840 47856 47803 47789 47784 48007 47767 47885
47897 47906 47821 47833 47793 47776 47831 47807 47787 47873 47791 47881 48002 47882 47864
47775 47846 47809 47816 47781 47756 47774 47820 47785 47773 47787 47776 48002 47878 47866
47809 47836 47764 47834 47856 47772 47816 47818 47782 47805 47783 47784 48013 47760 47877
47801 47776 47844 47772 47752 47769 47829 47781 47844 47797 47783 47779 48004 47767 47854
47763 47760 47828 47778 47795 47774 47815 47795 47841 47780 47785 47778 48001 47771 47890
47761 47857 47817 47815 47780 47834 47832 47773 47843 47780 47786 47793 48019 47753 47875
47774 47817 47827 47829 47774 47776 47828 47834 47860 47778 47787 47779 48006 47765 47854
47784 47795 47831 47777 47826 47743 47832 47779 47819 47799 47786 47768 48003 47743 47863
47827 47847 47801 47771 47784 47856 47833 47832 47826 47779 47770 47944 48005 47766 47882
47827 47844 47823 47774 47774 47782 47833 47774 47830 47786 47782 47776 48004 47803 47885
47796 47801 47824 47788 47771 47783 47857 47777 47775 47778 47760 47792 48002 47772 47884
47769 47838 47814 47775 47762 47788 47853 47764 47827 47780 47786 47765 48006 47772 47865
47819 47766 47846 47776 47779 47843 47831 47835 47777 47775 47786 47833 48001 47760 47888
47813 47822 47773 47775 47825 47845 47853 47842 47839 47773 47787 47779 48001 47801 47853
47754 47774 47807 47822 47822 47810 47817 47785 47827 47794 47784 47775 48002 47759 47864
47863 47786 47849 47777 47781 47854 47813 47754 47844 47781 47786 47786 48023 47791 47895
47770 47761 47819 47829 47781 47809 47818 47842 47840 47776 47788 47781 48002 47744 47864
47769 47806 47799 47784 47823 47750 47799 47817 47816 47781 47757 47775 48001 47750 47880
47770 47839 47793 47778 47781 47852 47801 47834 47776 47782 47788 47940 48003 47871 47880

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 47771 bytes 100%
1,000 47754 bytes -17 bytes 100%
10,000 47749 bytes -5 bytes 100%
100,000 47743 bytes -6 bytes 0.87%
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
48050 bytes +307 bytes (+0.64%) +205 bytes
48048 bytes +305 bytes (+0.64%) +203 bytes
48056 bytes +313 bytes (+0.66%) +211 bytes
47972 bytes +229 bytes (+0.48%) +127 bytes
47980 bytes +237 bytes (+0.50%) +135 bytes
47845 bytes +102 bytes (+0.21%)
47865 bytes +122 bytes (+0.26%) +20 bytes
47855 bytes +112 bytes (+0.23%) +10 bytes
47862 bytes +119 bytes (+0.25%) +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 38286 bytes -9457 bytes (-19.81%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 40508 bytes -7235 bytes (-15.15%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 41231 bytes -6512 bytes (-13.64%)
Brotli (Wikipedia) brotli brotli -q 11 43226 bytes -4517 bytes (-9.46%)
LZMA2 (Wikipedia) xz xz -9 43924 bytes -3819 bytes (-8.00%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 45717 bytes -2026 bytes (-4.24%)
ZSTD (Wikipedia) zstd zstd -19 46233 bytes -1510 bytes (-3.16%)

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