Choose a version:
33% The original file has 60127 bytes (58.7k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 19548 bytes (19.1k, 33%).

After GZIP compression these minified files vary in size:
Boot
  7490 bytes (7.3k)
CDN, direct link
Baidu
  6527 bytes (6.4k)
CDN, direct link
cdnjs
  6524 bytes (6.4k)
CDN, direct link
gzip -6 (default)
  6514 bytes (6.4k)
local copy
gzip -9
  6504 bytes (6.4k)
local copy
cdnhttps
  6492 bytes (6.3k)
CDN, direct link
unpkg
  6487 bytes (6.3k)
CDN, direct link
Yandex
  6482 bytes (6.3k)
CDN, direct link
jsdelivr
  6482 bytes (6.3k)
CDN, direct link
libdeflate -12
  6324 bytes (6.2k)
local copy
7zip -mx=9 -tgzip
  6321 bytes (6.2k)
local copy
pigz -11 -n
  6316 bytes (6.2k)
local copy
kzip -s0 -rn -b1
  6314 bytes (6.2k)
local copy
Zopfli
  6311 bytes (6.2k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/backbonejs/backbone-1.1.0.min.js

You will automatically get the smallest BackboneJS 1.1.0 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 171 bytes by using my BackboneJS 1.1.0 Zopfli version instead of the best available CDN (2.71% smaller than jsdelivr, 6311 vs. 6482 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 --mls8 --bsr15 --lazy --ohh

(found November 27, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 8  --mls8
block splitting recursion 15  --bsr15
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

Verify file integrity

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

MD5:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/1.1.0/backbone-min.js --location | md5sum
dd2e6c2643968f7932487454302f407d  -
curl --silent --compressed http://minime.stephan-brumme.com/files/backbonejs/backbone-1.1.0.min.zopfli.js.gz | md5sum
dd2e6c2643968f7932487454302f407d  -

SHA1:
curl --silent --compressed https://raw.githubusercontent.com/jashkenas/backbone/1.1.0/backbone-min.js --location | sha1sum
7c9117d7f9bc38159c7687a1b41b42a5c7d4e63f  -
curl --silent --compressed http://minime.stephan-brumme.com/files/backbonejs/backbone-1.1.0.min.zopfli.js.gz | sha1sum
7c9117d7f9bc38159c7687a1b41b42a5c7d4e63f  -

These CDNs send you the original file:
CDN Size (compressed) MD5 (uncompressed) Timestamp
Boot 7490 bytes dd2e6c2643968f7932487454302f407d (invalid)
cdnjs 6524 bytes dd2e6c2643968f7932487454302f407d (invalid)
cdnhttps 6492 bytes dd2e6c2643968f7932487454302f407d December 24, 2015 @ 07:32
unpkg 6487 bytes dd2e6c2643968f7932487454302f407d July 11, 2016 @ 16:18
Yandex 6482 bytes dd2e6c2643968f7932487454302f407d (invalid)
jsdelivr 6482 bytes dd2e6c2643968f7932487454302f407d (invalid)

And some CDNs send you a different file:
CDN Size (compressed) MD5 (uncompressed) Comment / Diff Timestamp
Baidu 6527 bytes 19adb37ed9f0968ced67889ba9f5f553 only whitespaces differ (invalid)

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

Other Versions

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

1.3.3, 1.3.2, 1.3.1, 1.3.0,
1.2.3, 1.2.2, 1.2.1, 1.2.0,
1.1.2, 1.1.1, 1.1.0,
1.0.0,
0.9.10, 0.9.9, 0.9.2, 0.9.1, 0.9.0,
0.3.3, 0.3.2, 0.3.1, 0.3.0,
0.2.0,
0.1.2, 0.1.1

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

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
6311 bytes -1 byte zopfli --i100000 --mls8 --bsr15 --lazy --ohh November 27, 2015 @ 17:44
6312 bytes -1 byte zopfli --i10000 --mls512 --bsr8 --lazy --ohh September 8, 2015 @ 12:54
6313 bytes zopfli --i100 --mls512 --bsr4 --lazy --ohh September 8, 2015 @ 11:32

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

Most recent activity on July 11, 2016 @ 16:18.

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
6317 6318 6317 6317 6311 6313 6317 6318 6316 6313 6318 6317 6318 6317 6317
6322 6317 6320 6320 6312 6315 6315 6321 6312 6314 6318 6313 6314 6313 6313
6312 6317 6313 6312 6312 6315 6315 6314 6314 6313 6315 6313 6313 6312 6313
6316 6317 6313 6315 6312 6315 6312 6315 6316 6312 6314 6315 6312 6313 6312
6313 6318 6311 6315 6312 6315 6315 6314 6312 6312 6314 6317 6313 6313 6313
6312 6313 6313 6315 6315 6315 6318 6319 6316 6314 6314 6316 6313 6313 6313
6315 6317 6313 6312 6312 6312 6315 6315 6315 6312 6315 6315 6314 6313 6313
6316 6317 6315 6315 6313 6315 6317 6321 6312 6317 6315 6315 6313 6313 6313
6313 6312 6313 6312 6312 6315 6315 6314 6312 6317 6315 6315 6312 6313 6313
6324 6317 6311 6314 6312 6312 6315 6312 6312 6317 6316 6317 6313 6313 6312
6315 6317 6318 6312 6312 6313 6315 6314 6314 6313 6315 6315 6314 6313 6313
6315 6317 6311 6315 6313 6313 6315 6314 6316 6313 6313 6315 6314 6315 6313
6312 6317 6311 6312 6312 6315 6315 6314 6314 6312 6315 6317 6312 6313 6312
6317 6317 6318 6318 6313 6318 6318 6314 6316 6313 6313 6315 6312 6313 6313
6312 6316 6313 6315 6316 6315 6315 6314 6315 6312 6315 6315 6312 6313 6313
6312 6317 6313 6315 6316 6315 6318 6320 6315 6312 6314 6315 6314 6313 6313
6312 6317 6311 6312 6312 6318 6318 6319 6312 6314 6315 6315 6313 6313 6313
6316 6317 6311 6315 6313 6315 6315 6314 6315 6312 6315 6315 6313 6313 6313
6312 6317 6311 6315 6312 6315 6315 6320 6312 6312 6315 6315 6313 6312 6313
6312 6317 6318 6312 6312 6313 6315 6312 6314 6312 6314 6317 6314 6313 6313
6312 6317 6311 6315 6312 6315 6315 6314 6315 6318 6313 6315 6312 6313 6313
6313 6317 6313 6316 6313 6315 6316 6313 6315 6312 6315 6315 6314 6313 6312
6312 6316 6313 6316 6313 6313 6317 6321 6312 6312 6317 6315 6313 6313 6312

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 6313 bytes 100%
1,000 6313 bytes 100%
10,000 6312 bytes -1 byte 100%
100,000 6311 bytes -1 byte 22.32%
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
6314 bytes +3 bytes (+0.05%)
6314 bytes +3 bytes (+0.05%)
6340 bytes +29 bytes (+0.46%) +26 bytes
6373 bytes +62 bytes (+0.98%) +59 bytes
6410 bytes +99 bytes (+1.57%) +96 bytes
6425 bytes +114 bytes (+1.81%) +111 bytes
6446 bytes +135 bytes (+2.14%) +132 bytes
6480 bytes +169 bytes (+2.68%) +166 bytes
6515 bytes +204 bytes (+3.23%) +201 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
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 5523 bytes -788 bytes (-12.49%)
Brotli (Wikipedia) brotli brotli -q 11 5870 bytes -441 bytes (-6.99%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 5937 bytes -374 bytes (-5.93%)
ZPAQ (Wikipedia) zpaq zpaq -method 69 6260 bytes -51 bytes (-0.81%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 6292 bytes -19 bytes (-0.30%)
ZSTD (Wikipedia) zstd zstd -19 6323 bytes +12 bytes (+0.19%)
LZMA2 (Wikipedia) xz xz -9 6364 bytes +53 bytes (+0.84%)

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