Choose a version:
31% The original file has 1601873 bytes (1,564.3k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 488882 bytes (477.4k, 31%).

After GZIP compression these minified files vary in size:
Boot
  151432 bytes (147.9k)
CDN
cdnjs
  124721 bytes (121.8k)
CDN
gzip -6 (default)
  123245 bytes (120.4k)
local copy
gzip -9
  122733 bytes (119.9k)
local copy
libdeflate -12
  118542 bytes (115.8k)
local copy
7zip -mx=9 -tgzip
  118479 bytes (115.7k)
local copy
pigz -11 -n
  118355 bytes (115.6k)
local copy
kzip -s0 -rn -b3
  118249 bytes (115.5k)
local copy
Zopfli
  118207 bytes (115.4k)
local copy
Zopfli (defluff)
  118200 bytes (115.4k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/ember/ember-2.15.3.min.js

You will automatically get the smallest Ember 2.15.3 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 6514 bytes by using my Ember 2.15.3 Zopfli version instead of the best available CDN (5.51% smaller than cdnjs, 118207 vs. 124721 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 --bsr8 --lazy --ohh

(found October 17, 2017)
Description Value Parameter
iterations 1000000  --i1000000
maximum blocks 8  --mb8
maximum length score 2048  --mls2048
block splitting recursion 8  --bsr8
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 7 more bytes (118200 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed http://builds.emberjs.com/tags/v2.15.3/ember.min.js --location | md5sum
6caa30c9361e90f9a7d85612d1627634  -
curl --silent --compressed http://minime.stephan-brumme.com/files/ember/ember-2.15.3.min.zopfli.js.gz | md5sum
6caa30c9361e90f9a7d85612d1627634  -

SHA1:
curl --silent --compressed http://builds.emberjs.com/tags/v2.15.3/ember.min.js --location | sha1sum
ae2f72c5005b73c2a3295b9f68e2cc6213caf4c8  -
curl --silent --compressed http://minime.stephan-brumme.com/files/ember/ember-2.15.3.min.zopfli.js.gz | sha1sum
ae2f72c5005b73c2a3295b9f68e2cc6213caf4c8  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 151432 bytes 6caa30c9361e90f9a7d85612d1627634 November 14, 2017 @ 17:09
cdnjs 124721 bytes 6caa30c9361e90f9a7d85612d1627634 October 12, 2017 @ 13:20

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

Other Versions

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

3.0.0,
2.18.2, 2.18.1, 2.18.0,
2.17.2, 2.17.1, 2.17.0,
2.16.2, 2.16.1, 2.16.0,
2.15.3, 2.15.2, 2.15.1, 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
118207 bytes -1 byte zopfli --i1000000 --mls2048 --bsr8 --lazy --ohh October 17, 2017 @ 17:24
118208 bytes -3 bytes zopfli --i100000 --mls2048 --bsr8 --lazy --ohh October 16, 2017 @ 15:18
118211 bytes -4 bytes zopfli --i100000 --mls1024 --bsr30 --lazy --ohh October 16, 2017 @ 13:06
118215 bytes -11 bytes zopfli --i10000 --mls1024 --bsr30 --lazy --ohh October 16, 2017 @ 11:03
118226 bytes -3 bytes zopfli --i1000 --mls1024 --bsr30 --lazy --ohh October 16, 2017 @ 10:44
118229 bytes -3 bytes zopfli --i1000 --mls1024 --bsr21 --lazy --ohh October 16, 2017 @ 10:40
118232 bytes -7 bytes zopfli --i1000 --mls4 --bsr16 --lazy --ohh October 16, 2017 @ 10:38
118239 bytes -2 bytes zopfli --i1000 --mls2048 --bsr14 --lazy --ohh October 16, 2017 @ 10:37
118241 bytes -3 bytes zopfli --i1000 --mls2 --bsr30 --lazy --ohh October 16, 2017 @ 10:36
118244 bytes -3 bytes zopfli --i1000 --mls1024 --bsr16 --lazy --ohh October 16, 2017 @ 10:35
118247 bytes zopfli --i100 --mls2 --bsr30 --lazy --ohh October 16, 2017 @ 10:20

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

Most recent activity on November 14, 2017 @ 17:09.

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
118243 118241 118241 118241 118234 118239 118242 118242 118241 118235 118224 118229 118254 118229 118287
118241 118233 118229 118218 118237 118221 118237 118240 118240 118243 118229 118219 118252 118233 118291
118229 118230 118237 118216 118216 118217 118236 118231 118231 118234 118218 118230 118283 118237 118257
118230 118229 118234 118217 118218 118215 118231 118243 118234 118232 118218 118232 118217 118228 118253
118229 118227 118248 118214 118233 118219 118236 118243 118245 118244 118207 118222 118249 118241 118246
118232 118217 118213 118217 118215 118216 118230 118233 118230 118231 118214 118216 118248 118220 118245
118225 118229 118247 118222 118226 118218 118236 118237 118250 118232 118218 118230 118247 118248 118282
118218 118215 118214 118219 118215 118217 118225 118227 118217 118219 118236 118216 118247 118245 118233
118213 118215 118215 118223 118216 118213 118228 118231 118230 118217 118218 118214 118249 118249 118290
118219 118219 118214 118218 118216 118217 118229 118229 118237 118234 118218 118228 118276 118245 118291
118236 118221 118220 118220 118218 118220 118228 118231 118231 118231 118219 118240 118247 118242 118245
118227 118217 118213 118222 118217 118219 118227 118216 118218 118219 118219 118218 118275 118248 118291
118214 118214 118213 118215 118215 118218 118219 118229 118218 118213 118219 118214 118264 118249 118294
118240 118215 118222 118216 118225 118224 118216 118229 118215 118220 118232 118234 118248 118247 118245
118228 118227 118227 118218 118231 118215 118242 118226 118234 118232 118234 118229 118247 118248 118282
118235 118231 118233 118221 118230 118216 118238 118231 118216 118214 118237 118220 118248 118248 118243
118215 118218 118214 118222 118233 118218 118234 118229 118231 118216 118234 118221 118248 118249 118291
118216 118217 118217 118215 118225 118215 118222 118219 118218 118218 118219 118219 118248 118249 118294
118235 118252 118240 118239 118235 118238 118239 118231 118231 118214 118233 118234 118247 118249 118246
118235 118219 118239 118218 118238 118244 118237 118229 118232 118230 118233 118219 118248 118249 118245
118214 118223 118218 118215 118218 118216 118227 118216 118217 118219 118233 118219 118246 118248 118257
118216 118216 118215 118222 118218 118215 118224 118229 118232 118211 118218 118215 118249 118234 118244
118214 118215 118217 118219 118217 118218 118217 118216 118216 118218 118233 118226 118248 118248 118243

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 118247 bytes 100%
1,000 118224 bytes -23 bytes 100%
10,000 118212 bytes -12 bytes 100%
100,000 118208 bytes -4 bytes 0.58%
1,000,000 118207 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
118303 bytes +96 bytes (+0.08%) +54 bytes
118319 bytes +112 bytes (+0.09%) +70 bytes
118284 bytes +77 bytes (+0.07%) +35 bytes
118249 bytes +42 bytes (+0.04%)
118280 bytes +73 bytes (+0.06%) +31 bytes
118311 bytes +104 bytes (+0.09%) +62 bytes
118319 bytes +112 bytes (+0.09%) +70 bytes
118250 bytes +43 bytes (+0.04%) +1 byte
118282 bytes +75 bytes (+0.06%) +33 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 81515 bytes -36692 bytes (-31.04%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 88476 bytes -29731 bytes (-25.15%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 95018 bytes -23189 bytes (-19.62%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 101358 bytes -16849 bytes (-14.25%)
Brotli (Wikipedia) brotli brotli -q 11 103206 bytes -15001 bytes (-12.69%)
LZMA2 (Wikipedia) xz xz -9 104792 bytes -13415 bytes (-11.35%)
ZSTD (Wikipedia) zstd zstd -19 107852 bytes -10355 bytes (-8.76%)

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 2018.
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