Choose a version:
45% The original file has 326788 bytes (319.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 146657 bytes (143.2k, 45%).

After GZIP compression these minified files vary in size:
Boot
  58524 bytes (57.2k)
CDN
jsdelivr
  58524 bytes (57.2k)
CDN
Baidu
  51589 bytes (50.4k)
CDN
cdnjs
  51581 bytes (50.4k)
CDN
unpkg
  51280 bytes (50.1k)
CDN
gzip -6 (default)
  51201 bytes (50.0k)
local copy
cdnhttps
  51185 bytes (50.0k)
CDN
gzip -9
  51031 bytes (49.8k)
local copy
libdeflate -12
  49392 bytes (48.2k)
local copy
7zip -mx=9 -tgzip
  49316 bytes (48.2k)
local copy
kzip -s0 -rn -b8
  49110 bytes (48.0k)
local copy
pigz -11 -n
  49076 bytes (47.9k)
local copy
Zopfli
  49004 bytes (47.9k)
local copy
Zopfli (defluff)
  49002 bytes (47.9k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-3.4.6.min.js

You will automatically get the smallest D3 3.4.6 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 2181 bytes by using my D3 3.4.6 Zopfli version instead of the best available CDN (4.45% smaller than cdnhttps, 49004 vs. 51185 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 --mls512 --bsr12 --lazy --ohh

(found December 22, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 512  --mls512
block splitting recursion 12  --bsr12
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 2 more bytes (49002 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/v3.4.6/d3.min.js --location | md5sum
4c149911f8bfa18330fd2b298cbbf9e2  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.4.6.min.zopfli.js.gz | md5sum
4c149911f8bfa18330fd2b298cbbf9e2  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.4.6/d3.min.js --location | sha1sum
59f9e89234578504980b0c77a389236a0b388df7  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.4.6.min.zopfli.js.gz | sha1sum
59f9e89234578504980b0c77a389236a0b388df7  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 58524 bytes 4c149911f8bfa18330fd2b298cbbf9e2 (invalid)
jsdelivr 58524 bytes 4c149911f8bfa18330fd2b298cbbf9e2 (invalid)
cdnjs 51581 bytes 4c149911f8bfa18330fd2b298cbbf9e2 (invalid)
unpkg 51280 bytes 4c149911f8bfa18330fd2b298cbbf9e2 July 11, 2016 @ 16:31
cdnhttps 51185 bytes 4c149911f8bfa18330fd2b298cbbf9e2 December 24, 2015 @ 07:33

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 51589 bytes f0106825f8986d800a22005c27d7d4fe 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:

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
49004 bytes -7 bytes zopfli --i100000 --mls512 --bsr12 --lazy --ohh December 22, 2015 @ 12:59
49011 bytes -8 bytes zopfli --i10000 --mls512 --bsr12 --lazy --ohh October 13, 2015 @ 19:53
49019 bytes -5 bytes zopfli --i1000 --mls512 --bsr12 --lazy --ohh September 19, 2015 @ 09:01
49024 bytes -1 byte zopfli --i1000 --mls512 --bsr16 --lazy --ohh September 19, 2015 @ 09:01
49025 bytes -8 bytes zopfli --i1000 --mls128 --bsr7 --lazy --ohh September 19, 2015 @ 08:58
49033 bytes -2 bytes zopfli --i1000 --mls512 --bsr7 --lazy --ohh September 19, 2015 @ 08:57
49035 bytes zopfli --i100 --mls32768 --bsr20 --lazy --ohh September 18, 2015 @ 19:47

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

Most recent activity on February 24, 2017 @ 07:32.

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
49171 49283 49216 49220 49166 49167 49141 49186 49151 49189 49266 49258 49272 49280 49281
49100 49071 49121 49050 49074 49129 49046 49119 49061 49031 49128 49137 49269 49268 49268
49065 49097 49131 49074 49078 49137 49037 49147 49047 49026 49270 49274 49271 49276 49283
49181 49160 49101 49059 49080 49121 49009 49113 49023 49123 49122 49154 49275 49267 49031
49160 49180 49093 49097 49093 49102 49058 49106 49018 49031 49140 49270 49276 49267 49267
49067 49163 49105 49077 49074 49106 49053 49112 49025 49120 49145 49118 49271 49107 49026
49074 49158 49110 49058 49082 49112 49045 49109 49019 49033 49124 49137 49276 49109 49027
49158 49092 49087 49066 49079 49082 49033 49104 49016 49028 49117 49139 49276 49026 49036
49055 49094 49065 49082 49075 49120 49089 49118 49004 49032 49124 49163 49276 49268 49031
49075 49163 49086 49063 49068 49087 49044 49108 49026 49026 49115 49131 49276 49107 49036
49069 49170 49102 49067 49069 49121 49058 49123 49009 49032 49123 49137 49273 49269 49033
49155 49092 49101 49067 49077 49088 49017 49108 49050 49121 49127 49118 49275 49269 49030
49087 49101 49064 49065 49103 49105 49117 49120 49017 49116 49125 49151 49271 49268 49032
49165 49168 49102 49059 49071 49106 49007 49108 49008 49118 49123 49124 49276 49110 49022
49159 49065 49056 49056 49077 49106 49023 49107 49027 49033 49123 49142 49275 49277 49037
49073 49162 49103 49078 49070 49083 49044 49111 49028 49030 49127 49120 49272 49269 49029
49108 49097 49110 49079 49077 49085 49055 49110 49025 49034 49125 49133 49271 49108 49023
49069 49095 49099 49099 49070 49139 49029 49108 49036 49026 49124 49149 49271 49105 49026
49150 49097 49107 49081 49076 49082 49043 49109 49023 49122 49125 49150 49271 49026 49031
49068 49172 49159 49158 49072 49118 49011 49112 49017 49123 49125 49118 49271 49108 49033
49057 49107 49112 49081 49048 49051 49011 49111 49027 49125 49125 49137 49269 49027 49033
49070 49164 49123 49069 49082 49086 49018 49107 49026 49035 49122 49122 49268 49025 49029
49168 49170 49109 49086 49080 49105 49023 49108 49026 49032 49127 49123 49271 49111 49022

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 49034 bytes 100%
1,000 49019 bytes -15 bytes 100%
10,000 49011 bytes -8 bytes 100%
100,000 49004 bytes -7 bytes 2.03%
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
49302 bytes +298 bytes (+0.61%) +192 bytes
49302 bytes +298 bytes (+0.61%) +192 bytes
49315 bytes +311 bytes (+0.63%) +205 bytes
49337 bytes +333 bytes (+0.68%) +227 bytes
49270 bytes +266 bytes (+0.54%) +160 bytes
49264 bytes +260 bytes (+0.53%) +154 bytes
49237 bytes +233 bytes (+0.48%) +127 bytes
49150 bytes +146 bytes (+0.30%) +40 bytes
49110 bytes +106 bytes (+0.22%)

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 39057 bytes -9947 bytes (-20.30%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 41484 bytes -7520 bytes (-15.35%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 42487 bytes -6517 bytes (-13.30%)
Brotli (Wikipedia) brotli brotli -q 11 44325 bytes -4679 bytes (-9.55%)
LZMA2 (Wikipedia) xz xz -9 44984 bytes -4020 bytes (-8.20%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 46835 bytes -2169 bytes (-4.43%)
ZSTD (Wikipedia) zstd zstd -19 47366 bytes -1638 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