Choose a version:
48% The original file has 559840 bytes (546.7k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 270375 bytes (264.0k, 48%).

After GZIP compression these minified files vary in size:
unpkg
  102319 bytes (99.9k)
CDN
Boot
  89214 bytes (87.1k)
CDN
cdnjs
  89214 bytes (87.1k)
CDN
gzip -6 (default)
  88697 bytes (86.6k)
local copy
gzip -9
  88409 bytes (86.3k)
local copy
libdeflate -12
  84891 bytes (82.9k)
local copy
7zip -mx=9 -tgzip
  84491 bytes (82.5k)
local copy
kzip -s0 -rn -b7
  84389 bytes (82.4k)
local copy
zultra
  84176 bytes (82.2k)
local copy
pigz -11 -n
  84056 bytes (82.1k)
local copy
Zopfli
  83927 bytes (82.0k)
local copy
Zopfli (defluff)
  83924 bytes (82.0k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/d3/d3-6.6.1.min.js (or via HTTPS)

You will automatically get the smallest D3 6.6.1 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 5287 bytes by using my D3 6.6.1 Zopfli version instead of the best available CDN (6.30% smaller than cdnjs, 83927 vs. 89214 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 --i1000000 --mb8 --mls32768 --bsr7 --lazy --ohh

(found March 29, 2021)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 32768  --mls32768
block splitting recursion 7  --bsr7
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 (83924 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/v6.6.1/d3.zip --location | md5sum
366ecb209880c3a9a34187cf67d264f9  -
curl --silent --compressed https://minime.stephan-brumme.com/files/d3/d3-6.6.1.min.zopfli.js.gz | md5sum
366ecb209880c3a9a34187cf67d264f9  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mbostock/d3/v6.6.1/d3.zip --location | sha1sum
63704501dc7931677554892ed31abd33c8c34e30  -
curl --silent --compressed https://minime.stephan-brumme.com/files/d3/d3-6.6.1.min.zopfli.js.gz | sha1sum
63704501dc7931677554892ed31abd33c8c34e30  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
unpkg 102319 bytes 366ecb209880c3a9a34187cf67d264f9 (invalid)
Boot 89214 bytes 366ecb209880c3a9a34187cf67d264f9 March 24, 2021 @ 19:22
cdnjs 89214 bytes 366ecb209880c3a9a34187cf67d264f9 March 24, 2021 @ 19:22

Note: only the MD5 hashes are shown to keep things simple.

Other Versions

Available D3 versions at minime.stephan-brumme.com:

6.6.2, 6.6.1, 6.6.0, 6.5.0, 6.4.0, 6.3.1, 6.2.0, 6.1.1, 6.1.0, 6.0.0,
5.16.0, 5.15.1, 5.15.0, 5.14.2, 5.14.1, 5.14.0, 5.13.1, 5.13.0, 5.12.0, 5.11.0, 5.10.1, 5.10.0,
5.9.7, 5.9.6, 5.9.5, 5.9.4, 5.9.3, 5.9.2, 5.9.1, 5.9.0, 5.8.2, 5.8.1, 5.8.0, 5.7.0, 5.6.0, 5.5.0, 5.4.0, 5.3.0, 5.2.0, 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
83927 bytes -3 bytes zopfli --i1000000 --mls32768 --bsr7 --lazy --ohh March 29, 2021 @ 20:12
83930 bytes -3 bytes zopfli --i100000 --mls32768 --bsr7 --lazy --ohh March 26, 2021 @ 19:41
83933 bytes -12 bytes zopfli --i10000 --mls32768 --bsr7 --lazy --ohh March 26, 2021 @ 17:50
83945 bytes -9 bytes zopfli --i1000 --mls32768 --bsr7 --lazy --ohh March 26, 2021 @ 17:26
83954 bytes -1 byte zopfli --i1000 --mls8192 --bsr12 --lazy --ohh March 26, 2021 @ 17:25
83955 bytes -16 bytes zopfli --i1000 --mls8192 --bsr22 --lazy --ohh March 26, 2021 @ 17:24
83971 bytes zopfli --i100 --mls32768 --bsr7 --lazy --ohh March 26, 2021 @ 16:56

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

Most recent activity on March 30, 2021 @ 08:10.

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, 100,000 or 1,000,000.
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
84252 84248 84437 84378 84350 84568 84407 84290 84393 84373 84193 84234 84173 84223 84291
84244 84573 84249 84235 84221 84219 84624 84054 84265 84051 84065 84243 84036 84274 84105
84074 84076 84286 83996 84028 84192 84021 84003 84207 84017 84103 83999 83960 83985 83975
84208 84196 84256 84238 83997 84238 84211 84195 84067 83994 84298 84078 84003 83997 83927
84326 84320 84358 84107 84149 84500 84376 84102 84283 84005 83996 84071 83990 84017 84014
84202 84235 84236 84226 83999 84221 84103 84113 84100 84000 83993 83998 83954 83936 84047
84213 84239 84235 84410 84005 84203 84192 84104 84097 83996 83997 84005 84016 83992 84053
84202 84213 84229 84412 84014 84206 83987 84002 84079 83996 84003 84000 83963 84394 84002
84083 84302 84235 84107 84003 84190 84192 84195 84200 83995 84001 84045 83946 84327 84059
84202 84212 84237 84199 84014 84215 84190 84190 84099 83995 83994 84020 84022 84160 84205
84194 84200 84237 84145 83997 84304 84198 83992 84195 84004 84105 84136 83954 84395 84228
84200 84198 84238 84204 83995 84211 84186 84196 84200 84020 84108 84164 83966 84397 84080
84200 84210 84406 84143 83999 84127 84194 84195 84104 83982 84013 84166 84091 84274 84210
84204 84217 84234 84204 84339 84207 84190 84113 84103 84008 83996 84190 83986 84270 84200
84210 84214 84217 84138 84341 84216 84191 84223 84099 84017 84018 84186 84322 84086 84206
84204 84213 84232 84208 83997 84212 83989 84193 84197 84030 83986 84193 84160 84284 84325
84222 84221 84335 84141 84344 84215 84192 84196 84102 83995 83990 84190 84111 84279 84084
84199 84202 84236 84201 84217 84196 83996 84102 84101 83997 83996 84003 83955 84285 84204
84204 84203 84235 84144 84012 84189 84193 84200 84101 83998 83996 84195 83945 84383 84328
84204 84213 84237 84141 84005 84211 84194 84193 84202 84000 83995 84186 84090 84086 84210
84204 84215 84234 84206 84221 84198 83994 84194 84203 83994 84100 84193 84111 84393 84145
84195 84213 84235 84199 84010 84209 84196 84194 84100 84000 84032 84196 84149 84282 84206
84338 84301 84233 84204 84216 84185 84190 84197 84199 84010 83998 84179 84090 84293 84200

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 83971 bytes 100%
1,000 83945 bytes -26 bytes 100%
10,000 83933 bytes -12 bytes 100%
100,000 83930 bytes -3 bytes 0.58%
1,000,000 83927 bytes -3 bytes 0.29%
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
84404 bytes +477 bytes (+0.57%) +15 bytes
85788 bytes +1861 bytes (+2.22%) +1399 bytes
85619 bytes +1692 bytes (+2.02%) +1230 bytes
84412 bytes +485 bytes (+0.58%) +23 bytes
84413 bytes +486 bytes (+0.58%) +24 bytes
84405 bytes +478 bytes (+0.57%) +16 bytes
84414 bytes +487 bytes (+0.58%) +25 bytes
84389 bytes +462 bytes (+0.55%)
84404 bytes +477 bytes (+0.57%) +15 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
However, support for Brotli is constantly growing - for example, your browser actually supports it !
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 65595 bytes -18332 bytes (-21.84%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 73077 bytes -10850 bytes (-12.93%)
LZMA2 (Wikipedia) xz xz -9 74176 bytes -9751 bytes (-11.62%)
Brotli (Wikipedia) brotli brotli -q 11 74364 bytes -9563 bytes (-11.39%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 74940 bytes -8987 bytes (-10.71%)
Zstandard (Wikipedia) zstd zstd -19 80102 bytes -3825 bytes (-4.56%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 82902 bytes -1025 bytes (-1.22%)

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 2021.
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

All trademarks are property of their respective owners. You know, the boring legal stuff.