Choose a version:
47% The original file has 298053 bytes (291.1k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 139114 bytes (135.9k, 47%).

After GZIP compression these minified files vary in size:
Boot
  54390 bytes (53.1k)
CDN, direct link
Baidu
  47430 bytes (46.3k)
CDN, direct link
cdnjs
  47419 bytes (46.3k)
CDN, direct link
gzip -6 (default)
  47088 bytes (46.0k)
local copy
cdnhttps
  47057 bytes (46.0k)
CDN, direct link
unpkg
  47006 bytes (45.9k)
CDN, direct link
gzip -9
  46929 bytes (45.8k)
local copy
libdeflate -12
  45394 bytes (44.3k)
local copy
7zip -mx=9 -tgzip
  45384 bytes (44.3k)
local copy
kzip -s0 -rn -b8
  45247 bytes (44.2k)
local copy
pigz -11 -n
  45199 bytes (44.1k)
local copy
Zopfli
  45100 bytes (44.0k)
local copy
Zopfli (defluff)
  45095 bytes (44.0k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-3.1.10.min.js

You will automatically get the smallest D3 3.1.10 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 1906 bytes by using my D3 3.1.10 Zopfli version instead of the best available CDN (4.23% smaller than unpkg, 45100 vs. 47006 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 --bsr10 --lazy --ohh

(found December 21, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 64  --mls64
block splitting recursion 10  --bsr10
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 5 more bytes (45095 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/v3.1.10/d3.min.js --location | md5sum
fcd6b8257bf56c2e9dc12adb891b3071  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.1.10.min.zopfli.js.gz | md5sum
fcd6b8257bf56c2e9dc12adb891b3071  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v3.1.10/d3.min.js --location | sha1sum
af6ef956b2e69dbecd0db2aab973264140b12113  -
curl --silent --compressed http://minime.stephan-brumme.com/files/d3/d3-3.1.10.min.zopfli.js.gz | sha1sum
af6ef956b2e69dbecd0db2aab973264140b12113  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 54390 bytes fcd6b8257bf56c2e9dc12adb891b3071 (invalid)
cdnjs 47419 bytes fcd6b8257bf56c2e9dc12adb891b3071 (invalid)
cdnhttps 47057 bytes fcd6b8257bf56c2e9dc12adb891b3071 December 24, 2015 @ 07:33
unpkg 47006 bytes fcd6b8257bf56c2e9dc12adb891b3071 July 11, 2016 @ 16:32

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 47430 bytes de9805aa0775182eaf472a3cc75b3d46 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
45100 bytes -4 bytes zopfli --i100000 --mls64 --bsr10 --lazy --ohh December 21, 2015 @ 14:27
45104 bytes -3 bytes zopfli --i10000 --mls64 --bsr10 --lazy --ohh November 23, 2015 @ 17:28
45107 bytes -5 bytes zopfli --i1000 --mls64 --bsr10 --lazy --ohh September 20, 2015 @ 07:55
45112 bytes -1 byte zopfli --i1000 --mls64 --bsr4 --lazy --ohh September 20, 2015 @ 07:53
45113 bytes -2 bytes zopfli --i1000 --mls32 --bsr7 --lazy --ohh September 20, 2015 @ 07:51
45115 bytes -6 bytes zopfli --i1000 --mls32 --bsr9 --lazy --ohh September 20, 2015 @ 07:50
45121 bytes zopfli --i100 --mls64 --bsr10 --lazy --ohh September 18, 2015 @ 22:24

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

Most recent activity on March 3, 2017 @ 10:46.

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
45290 45288 45286 45291 45165 45163 45289 45170 45288 45287 45288 45297 45310 45314 45316
45235 45254 45219 45236 45169 45107 45166 45135 45143 45173 45278 45303 45311 45310 45276
45132 45159 45131 45147 45117 45130 45130 45138 45176 45132 45138 45138 45311 45300 45205
45129 45162 45152 45196 45109 45151 45178 45169 45173 45139 45310 45206 45314 45300 45197
45180 45179 45123 45215 45151 45144 45204 45188 45291 45191 45196 45171 45308 45308 45192
45128 45120 45297 45186 45110 45139 45160 45185 45139 45131 45153 45265 45310 45309 45300
45149 45148 45125 45176 45117 45100 45164 45162 45132 45130 45196 45110 45309 45309 45292
45132 45134 45129 45158 45109 45124 45149 45172 45251 45126 45140 45125 45311 45309 45295
45128 45135 45123 45208 45121 45128 45212 45174 45146 45137 45148 45183 45309 45171 45176
45125 45125 45128 45141 45124 45161 45159 45155 45139 45133 45157 45137 45312 45171 45215
45123 45141 45129 45218 45109 45125 45170 45150 45145 45132 45145 45126 45307 45173 45296
45134 45124 45131 45163 45124 45123 45179 45141 45138 45133 45156 45241 45312 45311 45288
45124 45131 45180 45206 45109 45136 45166 45182 45132 45129 45127 45286 45311 45298 45291
45168 45122 45141 45219 45107 45168 45175 45180 45255 45130 45132 45192 45309 45300 45207
45137 45125 45133 45196 45128 45159 45144 45155 45191 45133 45162 45176 45311 45171 45286
45126 45127 45125 45187 45122 45158 45159 45161 45162 45197 45143 45135 45311 45298 45291
45124 45126 45135 45201 45147 45157 45167 45189 45149 45136 45149 45183 45319 45174 45194
45122 45126 45129 45201 45111 45125 45159 45182 45263 45132 45130 45265 45311 45175 45286
45127 45122 45127 45171 45108 45131 45179 45170 45193 45149 45159 45285 45312 45312 45200
45124 45133 45124 45173 45110 45125 45177 45185 45143 45134 45149 45124 45312 45309 45283
45128 45124 45124 45219 45112 45125 45175 45177 45135 45145 45153 45286 45319 45307 45184
45127 45125 45133 45186 45124 45123 45178 45170 45200 45137 45144 45129 45312 45300 45189
45127 45129 45125 45158 45110 45123 45202 45175 45156 45131 45141 45171 45311 45309 45210

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 45121 bytes 100%
1,000 45107 bytes -14 bytes 100%
10,000 45104 bytes -3 bytes 100%
100,000 45100 bytes -4 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
45324 bytes +224 bytes (+0.50%) +77 bytes
45331 bytes +231 bytes (+0.51%) +84 bytes
45329 bytes +229 bytes (+0.51%) +82 bytes
45332 bytes +232 bytes (+0.51%) +85 bytes
45356 bytes +256 bytes (+0.57%) +109 bytes
45335 bytes +235 bytes (+0.52%) +88 bytes
45328 bytes +228 bytes (+0.51%) +81 bytes
45283 bytes +183 bytes (+0.41%) +36 bytes
45247 bytes +147 bytes (+0.33%)

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 36205 bytes -8895 bytes (-19.72%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 38312 bytes -6788 bytes (-15.05%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 38808 bytes -6292 bytes (-13.95%)
Brotli (Wikipedia) brotli brotli -q 11 40814 bytes -4286 bytes (-9.50%)
LZMA2 (Wikipedia) xz xz -9 41528 bytes -3572 bytes (-7.92%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 43316 bytes -1784 bytes (-3.96%)
ZSTD (Wikipedia) zstd zstd -19 43491 bytes -1609 bytes (-3.57%)

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