Choose a version:
31% The original file has 1601417 bytes (1,563.9k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 488858 bytes (477.4k, 31%).

After GZIP compression these minified files vary in size:
Boot
  151414 bytes (147.9k)
CDN
cdnjs
  124701 bytes (121.8k)
CDN
gzip -6 (default)
  123226 bytes (120.3k)
local copy
gzip -9
  122712 bytes (119.8k)
local copy
libdeflate -12
  118472 bytes (115.7k)
local copy
7zip -mx=9 -tgzip
  118455 bytes (115.7k)
local copy
pigz -11 -n
  118328 bytes (115.6k)
local copy
kzip -s0 -rn -b3
  118231 bytes (115.5k)
local copy
Zopfli
  118184 bytes (115.4k)
local copy
Zopfli (defluff)
  118178 bytes (115.4k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/ember/ember-2.15.1.min.js (or via HTTPS)

You will automatically get the smallest Ember 2.15.1 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 6517 bytes by using my Ember 2.15.1 Zopfli version instead of the best available CDN (5.51% smaller than cdnjs, 118184 vs. 124701 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 October 6, 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 6 more bytes (118178 bytes).

Verify file integrity

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

MD5:
curl --silent --compressed https://builds.emberjs.com/tags/v2.15.1/ember.min.js --location | md5sum
9be4aa0f1472bb8210328a9d4bddb479  -
curl --silent --compressed https://minime.stephan-brumme.com/files/ember/ember-2.15.1.min.zopfli.js.gz | md5sum
9be4aa0f1472bb8210328a9d4bddb479  -

SHA1:
curl --silent --compressed https://builds.emberjs.com/tags/v2.15.1/ember.min.js --location | sha1sum
7d7ff008483d1734cc120cff9809a9c2fc160b27  -
curl --silent --compressed https://minime.stephan-brumme.com/files/ember/ember-2.15.1.min.zopfli.js.gz | sha1sum
7d7ff008483d1734cc120cff9809a9c2fc160b27  -

All listed CDNs deliver identical contents:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 151414 bytes 9be4aa0f1472bb8210328a9d4bddb479 October 11, 2017 @ 21:58
cdnjs 124701 bytes 9be4aa0f1472bb8210328a9d4bddb479 October 3, 2017 @ 08:19

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
118184 bytes -3 bytes zopfli --i1000000 --mls2048 --bsr7 --lazy --ohh October 6, 2017 @ 20:37
118187 bytes -2 bytes zopfli --i1000000 --mls4096 --bsr30 --lazy --ohh October 5, 2017 @ 14:52
118189 bytes -5 bytes zopfli --i100000 --mls4096 --bsr30 --lazy --ohh October 4, 2017 @ 15:26
118194 bytes -6 bytes zopfli --i10000 --mls4096 --bsr30 --lazy --ohh October 4, 2017 @ 13:23
118200 bytes -2 bytes zopfli --i1000 --mls4096 --bsr30 --lazy --ohh October 4, 2017 @ 12:12
118202 bytes -9 bytes zopfli --i1000 --mls4096 --bsr14 --lazy --ohh October 4, 2017 @ 11:52
118211 bytes -10 bytes zopfli --i1000 --mls4096 --bsr21 --lazy --ohh October 4, 2017 @ 11:49
118221 bytes -6 bytes zopfli --i1000 --mls256 --bsr11 --lazy --ohh October 4, 2017 @ 11:48
118227 bytes zopfli --i100 --mls2048 --bsr7 --lazy --ohh October 4, 2017 @ 10:36

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

Most recent activity on October 11, 2017 @ 21:58.

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 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
118218 118218 118218 118220 118209 118215 118216 118215 118219 118215 118202 118207 118233 118230 118272
118216 118215 118210 118193 118196 118200 118215 118218 118213 118219 118206 118195 118230 118211 118267
118208 118224 118195 118195 118194 118194 118217 118210 118206 118211 118197 118203 118261 118215 118234
118209 118209 118211 118197 118195 118195 118210 118222 118209 118208 118184 118206 118206 118205 118230
118205 118205 118224 118194 118213 118197 118218 118222 118222 118223 118191 118203 118227 118216 118222
118209 118217 118193 118193 118193 118195 118217 118212 118207 118207 118191 118194 118227 118198 118222
118202 118204 118196 118205 118206 118195 118215 118211 118207 118208 118197 118212 118227 118225 118265
118195 118196 118193 118198 118194 118193 118202 118203 118196 118197 118223 118213 118226 118224 118210
118192 118192 118192 118197 118194 118193 118206 118208 118207 118196 118197 118192 118227 118226 118269
118192 118194 118191 118193 118193 118194 118193 118207 118218 118211 118199 118192 118253 118222 118262
118214 118197 118198 118200 118198 118198 118204 118207 118206 118207 118196 118194 118227 118219 118219
118192 118195 118192 118199 118193 118195 118204 118194 118195 118196 118198 118198 118253 118225 118262
118193 118192 118193 118196 118193 118196 118193 118195 118197 118192 118198 118192 118242 118226 118265
118194 118193 118200 118194 118201 118200 118193 118206 118194 118196 118221 118213 118226 118225 118227
118204 118202 118203 118193 118207 118192 118209 118208 118209 118208 118211 118206 118226 118225 118260
118209 118195 118209 118193 118210 118193 118219 118207 118196 118195 118214 118197 118226 118226 118222
118193 118195 118193 118192 118194 118194 118211 118207 118208 118196 118217 118193 118226 118225 118261
118195 118195 118191 118195 118193 118194 118203 118196 118195 118197 118198 118197 118226 118226 118265
118217 118213 118218 118216 118213 118217 118215 118210 118207 118193 118215 118213 118226 118216 118223
118209 118199 118212 118197 118210 118200 118220 118207 118209 118206 118212 118212 118227 118226 118222
118193 118200 118198 118196 118196 118197 118204 118195 118196 118196 118212 118197 118225 118214 118235
118193 118196 118193 118199 118192 118193 118203 118210 118210 118194 118197 118187 118226 118214 118227
118193 118192 118197 118198 118194 118196 118195 118205 118194 118197 118211 118209 118227 118225 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 118227 bytes 100%
1,000 118200 bytes -27 bytes 100%
10,000 118190 bytes -10 bytes 100%
100,000 118187 bytes -3 bytes 0.58%
1,000,000 118184 bytes -3 bytes 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
118292 bytes +108 bytes (+0.09%) +61 bytes
118297 bytes +113 bytes (+0.10%) +66 bytes
118271 bytes +87 bytes (+0.07%) +40 bytes
118231 bytes +47 bytes (+0.04%)
118251 bytes +67 bytes (+0.06%) +20 bytes
118288 bytes +104 bytes (+0.09%) +57 bytes
118292 bytes +108 bytes (+0.09%) +61 bytes
118242 bytes +58 bytes (+0.05%) +11 bytes
118297 bytes +113 bytes (+0.10%) +66 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 - but your browser doesn't support it.
Algorithm Program Parameters Size Compared To Best Zopfli
ZPAQ (Wikipedia) zpaq zpaq -method 69 81487 bytes -36697 bytes (-31.05%)
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 88453 bytes -29731 bytes (-25.16%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 95005 bytes -23179 bytes (-19.61%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 101515 bytes -16669 bytes (-14.10%)
Brotli (Wikipedia) brotli brotli -q 11 103255 bytes -14929 bytes (-12.63%)
LZMA2 (Wikipedia) xz xz -9 104792 bytes -13392 bytes (-11.33%)
Zstandard (Wikipedia) zstd zstd -19 107830 bytes -10354 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