Choose a version:
51% The original file has 810421 bytes (791.4k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 409329 bytes (399.7k, 51%).

After GZIP compression these minified files vary in size:
Boot
  119171 bytes (116.4k)
CDN, direct link
cdnjs
  99577 bytes (97.2k)
CDN, direct link
gzip -6 (default)
  98646 bytes (96.3k)
local copy
cdnhttps
  98509 bytes (96.2k)
CDN, direct link
gzip -9
  98236 bytes (95.9k)
local copy
libdeflate -12
  94955 bytes (92.7k)
local copy
7zip -mx=9 -tgzip
  94878 bytes (92.7k)
local copy
pigz -11 -n
  94505 bytes (92.3k)
local copy
kzip -s0 -rn -b0
  94469 bytes (92.3k)
local copy
Zopfli
  94437 bytes (92.2k)
local copy
Zopfli (defluff)
  94434 bytes (92.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/threejs/three-r63.min.js

You will automatically get the smallest ThreeJS 63 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 4072 bytes by using my ThreeJS 63 Zopfli version instead of the best available CDN (4.31% smaller than cdnhttps, 94437 vs. 98509 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 --mls1024 --bsr20 --lazy --ohh

(found February 5, 2017)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 1024  --mls1024
block splitting recursion 20  --bsr20
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 (94434 bytes).

Verify file integrity

After decompression, my uncompressed files are identical to the original ones:

MD5:
curl --silent --compressed https://raw.githubusercontent.com/mrdoob/three.js/r63/build/three.min.js --location | md5sum
f54aa2c5e58f0593effc6a6db008b1ce  -
curl --silent --compressed http://minime.stephan-brumme.com/files/threejs/three-r63.min.zopfli.js.gz | md5sum
f54aa2c5e58f0593effc6a6db008b1ce  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/mrdoob/three.js/r63/build/three.min.js --location | sha1sum
aea390a05529a427e83adbacdf2e289410032973  -
curl --silent --compressed http://minime.stephan-brumme.com/files/threejs/three-r63.min.zopfli.js.gz | sha1sum
aea390a05529a427e83adbacdf2e289410032973  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 119171 bytes f54aa2c5e58f0593effc6a6db008b1ce (invalid)
cdnjs 99577 bytes f54aa2c5e58f0593effc6a6db008b1ce (invalid)
cdnhttps 98509 bytes f54aa2c5e58f0593effc6a6db008b1ce December 24, 2015 @ 07:36

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

Other Versions

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

86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Dojo, Ember, jQuery, Knockout, lodash, React, Socket.IO, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
94437 bytes -1 byte zopfli --i1000000 --mls1024 --bsr20 --lazy --ohh February 5, 2017 @ 08:52
94438 bytes -1 byte zopfli --i100000 --mls1024 --bsr20 --lazy --ohh December 28, 2015 @ 22:07
94439 bytes -5 bytes zopfli --i100000 --mls4096 --bsr7 --lazy --ohh December 28, 2015 @ 20:29
94444 bytes -4 bytes zopfli --i10000 --mls4096 --bsr7 --lazy --ohh November 17, 2015 @ 04:02
94448 bytes -4 bytes zopfli --i10000 --mls1024 --bsr23 --lazy --ohh November 17, 2015 @ 02:07
94452 bytes -30 bytes zopfli --i1000 --mls1024 --bsr20 --lazy --ohh November 16, 2015 @ 17:21
94482 bytes zopfli --i100 --mls1024 --bsr20 --lazy --ohh November 15, 2015 @ 10:12

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

Most recent activity on February 5, 2017 @ 14:30.

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
94727 94622 94611 94562 94609 94572 94574 94629 94568 94592 94559 94571 94606 94603 94589
94550 94554 94588 94560 94584 94540 94549 94546 94497 94455 94525 94739 94548 94598 94552
94652 94646 94619 94596 94670 94540 94549 94549 94547 94450 94721 94736 94555 94606 94724
94639 94648 94638 94655 94586 94548 94553 94494 94652 94494 94459 94439 94553 94583 94582
94673 94587 94711 94639 94545 94544 94602 94539 94478 94559 94516 94502 94559 94548 94559
94641 94628 94710 94554 94664 94644 94546 94543 94688 94550 94511 94485 94560 94548 94518
94594 94640 94614 94641 94651 94657 94652 94634 94476 94490 94560 94550 94542 94582 94542
94601 94704 94717 94722 94601 94654 94538 94624 94545 94537 94524 94493 94541 94602 94553
94603 94539 94598 94606 94597 94540 94555 94534 94538 94640 94568 94451 94547 94603 94562
94638 94641 94633 94628 94540 94603 94607 94601 94607 94599 94511 94452 94537 94593 94575
94633 94600 94637 94596 94609 94603 94542 94537 94607 94536 94567 94442 94536 94551 94565
94627 94594 94592 94592 94570 94547 94538 94536 94545 94535 94556 94454 94541 94577 94579
94637 94590 94597 94581 94527 94598 94606 94534 94657 94538 94564 94482 94535 94551 94539
94634 94640 94652 94621 94593 94609 94544 94535 94635 94601 94553 94452 94535 94577 94545
94590 94635 94528 94536 94528 94538 94545 94533 94540 94537 94514 94450 94538 94593 94565
94613 94641 94596 94588 94527 94661 94590 94603 94619 94559 94512 94486 94541 94596 94548
94633 94583 94628 94714 94644 94640 94545 94599 94478 94437 94512 94550 94539 94600 94564
94634 94634 94749 94587 94644 94652 94639 94653 94479 94539 94567 94450 94533 94593 94559
94603 94715 94702 94697 94651 94651 94643 94638 94540 94637 94506 94453 94539 94595 94539
94635 94547 94705 94622 94528 94656 94544 94593 94542 94444 94560 94451 94533 94556 94549
94598 94548 94595 94618 94531 94539 94541 94606 94478 94537 94561 94455 94540 94538 94557
94644 94632 94591 94584 94578 94541 94546 94533 94524 94539 94569 94451 94557 94602 94547
94636 94630 94596 94623 94539 94743 94679 94537 94526 94539 94565 94451 94527 94592 94553

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 94482 bytes 100%
1,000 94452 bytes -30 bytes 100%
10,000 94444 bytes -8 bytes 100%
100,000 94438 bytes -6 bytes 1.16%
1,000,000 94437 bytes -1 byte 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
94469 bytes +32 bytes (+0.03%)
94970 bytes +533 bytes (+0.56%) +501 bytes
94874 bytes +437 bytes (+0.46%) +405 bytes
94848 bytes +411 bytes (+0.44%) +379 bytes
94733 bytes +296 bytes (+0.31%) +264 bytes
94703 bytes +266 bytes (+0.28%) +234 bytes
94596 bytes +159 bytes (+0.17%) +127 bytes
94586 bytes +149 bytes (+0.16%) +117 bytes
94492 bytes +55 bytes (+0.06%) +23 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 64689 bytes -29748 bytes (-31.50%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 74252 bytes -20185 bytes (-21.37%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 79381 bytes -15056 bytes (-15.94%)
Brotli (Wikipedia) brotli brotli -q 11 80526 bytes -13911 bytes (-14.73%)
LZMA2 (Wikipedia) xz xz -9 81124 bytes -13313 bytes (-14.10%)
ZSTD (Wikipedia) zstd zstd -19 86238 bytes -8199 bytes (-8.68%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 86505 bytes -7932 bytes (-8.40%)

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