Choose a version:
24% The original file has 1031435 bytes (1,007.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 248786 bytes (243.0k, 24%).

After GZIP compression these minified files vary in size:
Boot
  84828 bytes (82.8k)
CDN, direct link
jsdelivr
  84828 bytes (82.8k)
CDN, direct link
Baidu
  70554 bytes (68.9k)
CDN, direct link
cdnjs
  70533 bytes (68.9k)
CDN, direct link
gzip -6 (default)
  69605 bytes (68.0k)
local copy
cdnhttps
  69516 bytes (67.9k)
CDN, direct link
gzip -9
  69256 bytes (67.6k)
local copy
7zip -mx=9 -tgzip
  66813 bytes (65.2k)
local copy
libdeflate -12
  66632 bytes (65.1k)
local copy
pigz -11 -n
  66618 bytes (65.1k)
local copy
kzip -s0 -rn -b1
  66590 bytes (65.0k)
local copy
Zopfli
  66504 bytes (64.9k)
local copy
Zopfli (defluff)
  66502 bytes (64.9k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/ember/ember-1.2.0.min.js

You will automatically get the smallest Ember 1.2.0 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 3012 bytes by using my Ember 1.2.0 Zopfli version instead of the best available CDN (4.53% smaller than cdnhttps, 66504 vs. 69516 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 --mls4096 --bsr18 --lazy --ohh

(found March 26, 2017)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 4096  --mls4096
block splitting recursion 18  --bsr18
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 (66502 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://builds.emberjs.com/tags/v1.2.0/ember.min.js --location | md5sum
61f82df6fff26622c6607c539f729a67  -
curl --silent --compressed http://minime.stephan-brumme.com/files/ember/ember-1.2.0.min.zopfli.js.gz | md5sum
61f82df6fff26622c6607c539f729a67  -

SHA1:
curl --silent --compressed http://builds.emberjs.com/tags/v1.2.0/ember.min.js --location | sha1sum
793ecd7788f4c7732fda579b43f9af28b4e26080  -
curl --silent --compressed http://minime.stephan-brumme.com/files/ember/ember-1.2.0.min.zopfli.js.gz | sha1sum
793ecd7788f4c7732fda579b43f9af28b4e26080  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 84828 bytes 61f82df6fff26622c6607c539f729a67 March 19, 2015 @ 17:45
jsdelivr 84828 bytes 61f82df6fff26622c6607c539f729a67 August 7, 2014 @ 19:17
cdnjs 70533 bytes 61f82df6fff26622c6607c539f729a67 January 13, 2014 @ 19:17
cdnhttps 69516 bytes 61f82df6fff26622c6607c539f729a67 December 24, 2015 @ 07:33

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 70554 bytes 4f75101a97d9f1496bc4eda12f49b857 only whitespaces differ June 5, 2014 @ 10:05

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

Other Versions

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

2.14.1, 2.14.0,
2.13.4, 2.13.3, 2.13.2, 2.13.1, 2.13.0,
2.12.2, 2.12.1, 2.12.0,
2.11.3, 2.11.2, 2.11.1, 2.11.0,
2.10.2, 2.10.1, 2.10.0,
2.9.1, 2.9.0,
2.8.3, 2.8.2, 2.8.1, 2.8.0,
2.7.3, 2.7.2, 2.7.1, 2.7.0,
2.6.2, 2.6.1, 2.6.0,
2.5.1, 2.5.0,
2.4.6, 2.4.5, 2.4.4, 2.4.3, 2.4.2, 2.4.1, 2.4.0,
2.3.1, 2.3.0,
2.2.2, 2.2.1, 2.2.0,
2.1.2, 2.1.1, 2.1.0,
2.0.3, 2.0.2, 2.0.1, 2.0.0,
1.13.13, 1.13.12, 1.13.11, 1.13.10, 1.13.9, 1.13.8, 1.13.7, 1.13.6, 1.13.5, 1.13.4, 1.13.3, 1.13.2, 1.13.1, 1.13.0,
1.12.2, 1.12.1, 1.12.0,
1.11.4, 1.11.3, 1.11.2, 1.11.1, 1.11.0,
1.10.1, 1.10.0,
1.9.1, 1.9.0,
1.8.1, 1.8.0,
1.7.1, 1.7.0,
1.6.1, 1.6.0,
1.5.1, 1.5.0,
1.4.0,
1.3.2, 1.3.1, 1.3.0,
1.2.2, 1.2.1, 1.2.0,
1.0.1, 1.0.0

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

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
66504 bytes -1 byte zopfli --i100000 --mls4096 --bsr18 --lazy --ohh March 26, 2017 @ 22:31
66505 bytes -1 byte zopfli --i100000 --mls4096 --bsr12 --lazy --ohh July 23, 2016 @ 02:25
66506 bytes -1 byte zopfli --i100000 --mls2 --bsr40 --lazy --ohh November 21, 2015 @ 09:31
66507 bytes -6 bytes zopfli --i10000 --mls2 --bsr19 --lazy --ohh October 2, 2015 @ 19:47
66513 bytes -1 byte zopfli --i1000 --mls2 --bsr19 --lazy --ohh October 2, 2015 @ 19:21
66514 bytes -18 bytes zopfli --i1000 --mls512 --bsr18 --lazy --ohh October 2, 2015 @ 18:49
66532 bytes zopfli --i100 --mls512 --bsr18 --lazy --ohh September 30, 2015 @ 09:08

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

Most recent activity on March 28, 2017 @ 12:54.

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
66515 66517 66512 66512 66514 66511 66510 66511 66512 66513 66512 66513 66516 66515 66518
66516 66515 66513 66516 66507 66512 66508 66509 66509 66510 66509 66507 66511 66515 66515
66513 66513 66513 66509 66509 66511 66515 66508 66509 66509 66509 66508 66512 66511 66514
66516 66514 66515 66509 66515 66514 66514 66508 66509 66507 66509 66509 66513 66521 66513
66513 66512 66511 66514 66513 66515 66515 66512 66510 66511 66511 66508 66513 66524 66513
66513 66512 66509 66509 66513 66512 66514 66509 66509 66509 66509 66508 66511 66514 66523
66514 66514 66510 66509 66516 66513 66508 66508 66509 66510 66508 66508 66512 66523 66512
66511 66513 66509 66508 66510 66516 66514 66511 66509 66507 66509 66508 66513 66513 66514
66511 66513 66512 66509 66511 66511 66515 66508 66507 66509 66509 66505 66516 66525 66513
66511 66513 66511 66509 66512 66511 66515 66512 66509 66508 66509 66507 66515 66524 66513
66512 66513 66514 66509 66509 66514 66515 66508 66508 66510 66509 66509 66512 66516 66514
66512 66513 66513 66509 66510 66514 66513 66508 66508 66508 66508 66508 66514 66521 66514
66513 66511 66511 66508 66512 66511 66514 66508 66509 66510 66509 66509 66512 66521 66513
66514 66512 66508 66508 66511 66514 66515 66509 66509 66508 66510 66507 66512 66520 66513
66506 66512 66509 66508 66512 66508 66508 66509 66508 66510 66508 66504 66514 66521 66511
66506 66514 66513 66508 66516 66513 66514 66510 66508 66507 66509 66508 66513 66521 66512
66508 66508 66511 66509 66510 66513 66516 66508 66509 66508 66509 66509 66511 66521 66509
66514 66515 66511 66509 66510 66514 66515 66509 66513 66510 66509 66507 66511 66520 66515
66514 66514 66511 66511 66510 66513 66514 66509 66509 66510 66509 66509 66511 66521 66513
66514 66513 66516 66517 66510 66513 66514 66509 66509 66509 66508 66506 66512 66518 66514
66511 66514 66510 66513 66512 66513 66514 66509 66509 66509 66508 66509 66512 66517 66512
66512 66514 66513 66509 66514 66515 66514 66509 66508 66508 66509 66508 66514 66518 66511
66506 66514 66513 66509 66518 66516 66514 66512 66508 66507 66509 66509 66515 66521 66512

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 66532 bytes 100%
1,000 66513 bytes -19 bytes 100%
10,000 66506 bytes -7 bytes 100%
100,000 66504 bytes -2 bytes 2.32%
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
66632 bytes +128 bytes (+0.19%) +42 bytes
66590 bytes +86 bytes (+0.13%)
66630 bytes +126 bytes (+0.19%) +40 bytes
66642 bytes +138 bytes (+0.21%) +52 bytes
66636 bytes +132 bytes (+0.20%) +46 bytes
66682 bytes +178 bytes (+0.27%) +92 bytes
66704 bytes +200 bytes (+0.30%) +114 bytes
66750 bytes +246 bytes (+0.37%) +160 bytes
66764 bytes +260 bytes (+0.39%) +174 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 48337 bytes -18167 bytes (-27.32%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 51195 bytes -15309 bytes (-23.02%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 55084 bytes -11420 bytes (-17.17%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 58173 bytes -8331 bytes (-12.53%)
Brotli (Wikipedia) brotli brotli -q 11 59298 bytes -7206 bytes (-10.84%)
LZMA2 (Wikipedia) xz xz -9 61076 bytes -5428 bytes (-8.16%)
ZSTD (Wikipedia) zstd zstd -19 62667 bytes -3837 bytes (-5.77%)

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