Choose a version:
31% The original file has 1601043 bytes (1,563.5k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 488726 bytes (477.3k, 31%).

After GZIP compression these minified files vary in size:
Boot
  151334 bytes (147.8k)
CDN, direct link
cdnjs
  124712 bytes (121.8k)
CDN, direct link
gzip -6 (default)
  123228 bytes (120.3k)
local copy
gzip -9
  122720 bytes (119.8k)
local copy
libdeflate -12
  118513 bytes (115.7k)
local copy
7zip -mx=9 -tgzip
  118456 bytes (115.7k)
local copy
pigz -11 -n
  118340 bytes (115.6k)
local copy
kzip -s0 -rn -b3
  118213 bytes (115.4k)
local copy
Zopfli
  118187 bytes (115.4k)
local copy
Zopfli (defluff)
  118182 bytes (115.4k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/ember/ember-2.15.0.min.js

You will automatically get the smallest Ember 2.15.0 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 6525 bytes by using my Ember 2.15.0 Zopfli version instead of the best available CDN (5.52% smaller than cdnjs, 118187 vs. 124712 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 --mls2048 --bsr7 --lazy --ohh

(found September 5, 2017)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 2048  --mls2048
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 5 more bytes (118182 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://builds.emberjs.com/tags/v2.15.0/ember.min.js --location | md5sum
b2184ff0bc6e68bfc986ed5d1e7c25e0  -
curl --silent --compressed http://minime.stephan-brumme.com/files/ember/ember-2.15.0.min.zopfli.js.gz | md5sum
b2184ff0bc6e68bfc986ed5d1e7c25e0  -

SHA1:
curl --silent --compressed http://builds.emberjs.com/tags/v2.15.0/ember.min.js --location | sha1sum
5c5158ca89d00b611512f2da58163a1e713a3194  -
curl --silent --compressed http://minime.stephan-brumme.com/files/ember/ember-2.15.0.min.zopfli.js.gz | sha1sum
5c5158ca89d00b611512f2da58163a1e713a3194  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 151334 bytes b2184ff0bc6e68bfc986ed5d1e7c25e0 September 4, 2017 @ 06:33
cdnjs 124712 bytes b2184ff0bc6e68bfc986ed5d1e7c25e0 August 31, 2017 @ 18:34

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

Other Versions

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

2.15.0,
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
118187 bytes -1 byte zopfli --i1000000 --mls2048 --bsr7 --lazy --ohh September 5, 2017 @ 13:18
118188 bytes -4 bytes zopfli --i100000 --mls2048 --bsr7 --lazy --ohh September 4, 2017 @ 15:30
118192 bytes -3 bytes zopfli --i10000 --mls2048 --bsr7 --lazy --ohh September 4, 2017 @ 13:28
118195 bytes -8 bytes zopfli --i10000 --mls256 --bsr11 --lazy --ohh September 4, 2017 @ 13:17
118203 bytes -4 bytes zopfli --i1000 --mls2048 --bsr7 --lazy --ohh September 4, 2017 @ 13:12
118207 bytes -19 bytes zopfli --i1000 --mls256 --bsr11 --lazy --ohh September 4, 2017 @ 13:05
118226 bytes zopfli --i100 --mls256 --bsr11 --lazy --ohh September 4, 2017 @ 12:46

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

Most recent activity on September 7, 2017 @ 06:31.

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
118211 118212 118212 118213 118203 118208 118214 118209 118211 118204 118204 118204 118235 118231 118270
118207 118208 118206 118195 118211 118206 118214 118214 118220 118201 118211 118199 118234 118212 118265
118206 118214 118194 118195 118196 118196 118212 118208 118206 118214 118200 118229 118263 118219 118232
118205 118209 118206 118194 118197 118207 118207 118219 118209 118206 118187 118226 118213 118208 118229
118198 118198 118223 118198 118205 118198 118214 118217 118217 118221 118189 118205 118230 118218 118218
118208 118214 118195 118193 118195 118195 118209 118209 118206 118206 118187 118217 118229 118218 118225
118203 118206 118198 118202 118194 118196 118212 118213 118206 118214 118197 118210 118228 118219 118263
118193 118193 118193 118198 118194 118197 118196 118195 118201 118198 118216 118216 118229 118215 118210
118193 118193 118195 118197 118193 118194 118199 118200 118207 118196 118198 118195 118230 118226 118255
118194 118197 118193 118193 118195 118195 118204 118205 118210 118209 118214 118214 118256 118223 118267
118205 118200 118201 118199 118197 118198 118196 118201 118198 118206 118198 118216 118229 118218 118219
118195 118196 118193 118199 118194 118194 118196 118194 118196 118198 118219 118198 118255 118225 118267
118194 118194 118191 118198 118193 118199 118195 118204 118196 118194 118198 118223 118250 118225 118270
118194 118194 118202 118196 118201 118202 118200 118208 118196 118196 118214 118215 118229 118225 118222
118196 118197 118202 118193 118206 118194 118209 118205 118209 118205 118211 118201 118228 118225 118263
118208 118198 118198 118195 118207 118194 118212 118199 118196 118196 118210 118215 118229 118219 118265
118195 118196 118193 118193 118191 118198 118210 118219 118207 118197 118199 118214 118229 118226 118264
118196 118195 118194 118197 118195 118195 118204 118197 118196 118195 118197 118195 118229 118226 118270
118208 118212 118214 118209 118213 118214 118213 118208 118202 118191 118214 118218 118228 118219 118222
118196 118196 118210 118197 118215 118218 118212 118212 118208 118206 118212 118214 118230 118223 118222
118194 118203 118200 118197 118194 118199 118201 118195 118196 118197 118212 118200 118227 118218 118238
118193 118198 118196 118199 118197 118196 118203 118210 118205 118208 118198 118194 118230 118210 118226
118194 118195 118197 118197 118194 118197 118209 118196 118195 118195 118214 118204 118229 118215 118220

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 118226 bytes 100%
1,000 118203 bytes -23 bytes 100%
10,000 118192 bytes -11 bytes 100%
100,000 118188 bytes -4 bytes 1.74%
1,000,000 118187 bytes -1 byte 0.58%
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
118272 bytes +85 bytes (+0.07%) +59 bytes
118283 bytes +96 bytes (+0.08%) +70 bytes
118274 bytes +87 bytes (+0.07%) +61 bytes
118213 bytes +26 bytes (+0.02%)
118254 bytes +67 bytes (+0.06%) +41 bytes
118294 bytes +107 bytes (+0.09%) +81 bytes
118285 bytes +98 bytes (+0.08%) +72 bytes
118226 bytes +39 bytes (+0.03%) +13 bytes
118273 bytes +86 bytes (+0.07%) +60 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 81478 bytes -36709 bytes (-31.06%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 88446 bytes -29741 bytes (-25.16%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 94982 bytes -23205 bytes (-19.63%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 101317 bytes -16870 bytes (-14.27%)
Brotli (Wikipedia) brotli brotli -q 11 103114 bytes -15073 bytes (-12.75%)
LZMA2 (Wikipedia) xz xz -9 104768 bytes -13419 bytes (-11.35%)
ZSTD (Wikipedia) zstd zstd -19 107823 bytes -10364 bytes (-8.77%)

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