<s>
Brotli	B-Application
is	O
a	O
lossless	B-Algorithm
data	I-Algorithm
compression	I-Algorithm
algorithm	I-Algorithm
developed	O
by	O
Google	B-Application
.	I-Application
</s>
<s>
It	O
uses	O
a	O
combination	O
of	O
the	O
general-purpose	O
LZ77	B-Algorithm
lossless	B-Algorithm
compression	I-Algorithm
algorithm	O
,	O
Huffman	B-General_Concept
coding	I-General_Concept
and	O
2nd-order	O
context	O
modelling	O
.	O
</s>
<s>
Dropbox	B-Application
reimplemented	O
Brotli	B-Application
in	O
Rust	B-Application
,	O
mainly	O
to	O
make	O
it	O
secure	O
to	O
modified	O
bytes	O
by	O
modified	O
or	O
hostile	O
clients	O
,	O
and	O
make	O
it	O
deterministic	O
.	O
</s>
<s>
Later	O
they	O
added	O
an	O
option	O
so	O
one	O
can	O
append	O
to	O
a	O
brotli	B-Application
file	O
.	O
</s>
<s>
Brotli	B-Application
is	O
primarily	O
used	O
by	O
web	B-Application
servers	I-Application
and	O
content	B-Operating_System
delivery	I-Operating_System
networks	I-Operating_System
to	O
compress	B-Protocol
HTTP	I-Protocol
content	I-Protocol
,	O
making	O
internet	O
websites	O
load	O
faster	O
.	O
</s>
<s>
A	O
successor	O
to	O
gzip	B-Application
,	O
it	O
is	O
supported	O
by	O
all	O
major	O
web	O
browsers	O
and	O
has	O
become	O
increasingly	O
popular	O
,	O
as	O
it	O
provides	O
better	O
compression	O
than	O
gzip	B-Application
.	O
</s>
<s>
Google	B-Application
employees	O
Jyrki	O
Alakuijala	O
and	O
Zoltán	B-Application
Szabadka	I-Application
initially	O
developed	O
Brotli	B-Application
in	O
2013	O
to	O
decrease	O
the	O
size	O
of	O
transmissions	O
of	O
WOFF	O
web	O
font	O
.	O
</s>
<s>
Alakuijala	O
and	O
Szabadka	O
completed	O
the	O
Brotli	B-Application
specification	O
during	O
20132016	O
.	O
</s>
<s>
The	O
specification	O
was	O
accompanied	O
with	O
a	O
reference	O
implementation	O
developed	O
by	O
two	O
additional	O
authors	O
,	O
Evgenii	O
Kliuchnikov	O
and	O
Lode	O
Vandevenne	O
,	O
who	O
had	O
previously	O
developed	O
Google	B-Application
's	I-Application
zopfli	B-Application
implementation	O
of	O
deflate	B-Algorithm
and	O
gzip	B-Application
compatible	O
compression	O
in	O
2013	O
.	O
</s>
<s>
Unlike	O
zopfli	B-Application
,	O
which	O
was	O
a	O
reimplementation	O
of	O
an	O
existing	O
data	O
format	O
specification	O
,	O
Brotli	B-Application
was	O
a	O
new	O
data	O
format	O
and	O
allowed	O
the	O
authors	O
to	O
improve	O
compression	O
ratios	O
even	O
further	O
.	O
</s>
<s>
The	O
Brotli	B-Application
specification	O
was	O
generalized	O
in	O
September	O
2015	O
for	O
HTTP	O
stream	O
compression	O
(	O
content-encoding	O
type	O
"	O
br	O
"	O
)	O
.	O
</s>
<s>
The	O
version	O
of	O
Brotli	B-Application
released	O
in	O
September	O
2015	O
by	O
the	B-Application
Google	I-Application
software	O
engineers	O
contained	O
enhancements	O
in	O
generic	O
lossless	B-Algorithm
data	I-Algorithm
compression	I-Algorithm
,	O
with	O
particular	O
emphasis	O
on	O
use	O
for	O
HTTP	B-Protocol
compression	I-Protocol
.	O
</s>
<s>
The	O
Internet	O
Engineering	O
Task	O
Force	O
approved	O
the	O
Brotli	B-Application
compressed	B-General_Concept
data	I-General_Concept
format	O
specification	O
as	O
an	O
informational	O
request	O
for	O
comment	O
(	O
)	O
in	O
July	O
2016	O
.	O
</s>
<s>
The	O
Brotli	B-Application
data	O
format	O
is	O
an	O
integral	O
part	O
of	O
the	O
2nd	O
iteration	O
of	O
the	O
Web	O
Open	O
Font	O
Format	O
,	O
which	O
was	O
recognized	O
in	O
a	O
2021	O
Technology	O
&	O
Engineering	O
Emmy	O
Award	O
from	O
the	O
National	O
Academy	O
of	O
Television	O
Arts	O
&	O
Sciences	O
for	O
font	O
technology	O
standardization	O
at	O
W3C	O
.	O
</s>
<s>
Brotli	B-Application
support	O
has	O
been	O
added	O
over	O
the	O
years	O
to	O
web	O
browsers	O
,	O
with	O
96%	O
of	O
worldwide	O
users	O
using	O
a	O
browser	O
that	O
supports	O
the	O
format	O
,	O
as	O
of	O
July	O
2022	O
.	O
</s>
<s>
In	O
2016	O
Dropbox	B-Application
reimplemented	O
Brotli	B-Application
in	O
Rust	B-Application
to	O
fulfill	O
their	O
requirement	O
to	O
be	O
more	O
secure	O
against	O
a	O
malicious	O
client	O
.	O
</s>
<s>
In	O
2018	O
they	O
implemented	O
the	O
missing	O
feature	O
so	O
one	O
can	O
append	O
to	O
a	O
Brotli	B-Application
compressed	O
file	O
.	O
</s>
<s>
Brotli	B-Application
's	O
new	O
file	O
format	O
allows	O
its	O
authors	O
to	O
improve	O
upon	O
Deflate	B-Algorithm
by	O
several	O
algorithmic	O
and	O
format-level	O
improvements	O
:	O
the	O
use	O
of	O
context	O
models	O
for	O
literals	O
and	O
copy	O
distances	O
,	O
describing	O
copy	O
distances	O
through	O
past	O
distances	O
,	O
use	O
of	O
move-to-front	O
queue	O
in	O
entropy	O
code	O
selection	O
,	O
joint-entropy	O
coding	O
of	O
literal	O
and	O
copy	O
lengths	O
,	O
the	O
use	O
of	O
graph	O
algorithms	O
in	O
block	O
splitting	O
,	O
and	O
a	O
larger	O
backward	O
reference	O
window	O
are	O
example	O
improvements	O
.	O
</s>
<s>
Unlike	O
most	O
general-purpose	O
compression	B-General_Concept
algorithms	I-General_Concept
,	O
Brotli	B-Application
uses	O
a	O
predefined	O
dictionary	O
,	O
roughly	O
120KiB	O
in	O
size	O
,	O
in	O
addition	O
to	O
the	O
dynamically	O
populated	O
(	O
"	O
sliding	O
window	O
"	O
)	O
dictionary	O
.	O
</s>
<s>
However	O
,	O
according	O
to	O
Alakuijala	O
,	O
the	O
predefined	O
dictionary	O
does	O
not	O
distract	O
from	O
Brotli	B-Application
's	O
general-ness	O
,	O
and	O
is	O
not	O
the	O
main	O
reason	O
for	O
improved	O
compression	O
.	O
</s>
<s>
Brotli	B-Application
with	O
an	O
all-zero	O
dictionary	O
still	O
performs	O
well	O
on	O
web	O
content	O
due	O
to	O
the	O
algorithmic	O
advances	O
,	O
he	O
claims	O
.	O
</s>
<s>
Brotli	B-Application
's	O
sliding	O
window	O
is	O
limited	O
to	O
16	O
MiB	O
.	O
</s>
<s>
This	O
enables	O
decoding	O
on	O
mobile	O
phones	O
with	O
limited	O
resources	O
,	O
but	O
makes	O
Brotli	B-Application
underperform	O
on	O
compression	O
benchmarks	O
having	O
larger	O
files	O
.	O
</s>
<s>
The	O
constraints	O
of	O
the	O
small	O
window	O
size	O
can	O
be	O
alleviated	O
by	O
using	O
Large	B-Application
Window	I-Application
Brotli	I-Application
,	O
which	O
is	O
not	O
compatible	O
with	O
RFC7932	O
(	O
Brotli	B-Application
proper	O
)	O
.	O
</s>
<s>
While	O
Google	B-Application
's	I-Application
zopfli	B-Application
implementation	O
of	O
the	O
deflate	B-Algorithm
compression	I-Algorithm
algorithm	I-Algorithm
is	O
named	O
after	O
zöpfli	O
,	O
the	O
Swiss	O
German	O
word	O
for	O
a	O
snack-sized	O
braided	O
buttery	O
bread	O
,	O
brotli	B-Application
is	O
named	O
after	O
brötli	O
,	O
the	O
Swiss	O
German	O
word	O
for	O
a	O
bread	O
roll	O
.	O
</s>
<s>
Google	B-Application
's	I-Application
own	O
implementation	O
of	O
the	O
Brotli	B-Application
specification	O
was	O
released	O
under	O
the	O
terms	O
of	O
the	O
permissive	B-License
free	I-License
software	I-License
MIT	B-License
license	I-License
in	O
2016	O
.	O
</s>
<s>
A	O
formal	O
validation	O
of	O
the	O
Brotli	B-Application
specification	O
was	O
independently	O
implemented	O
by	O
Mark	O
Adler	O
,	O
one	O
of	O
the	O
co-authors	O
of	O
the	O
zlib/gzip	O
compression	O
format	O
and	O
library	O
.	O
</s>
<s>
Adler	O
's	O
implementation	O
was	O
released	O
under	O
the	O
terms	O
of	O
the	O
similarly	O
permissive	O
Apache	B-Application
license	I-Application
.	O
</s>
<s>
Other	O
implementations	O
of	O
the	O
specification	O
also	O
exist	O
,	O
including	O
one	O
in	O
the	O
source-to-source	O
Haxe	B-Language
language	O
.	O
</s>
<s>
Brotli	B-Application
compression	I-Application
is	O
generally	O
used	O
as	O
an	O
alternative	O
to	O
gzip	B-Application
on	O
the	O
web	O
,	O
as	O
Brotli	B-Application
provides	O
better	O
overall	O
compression	O
.	O
</s>
<s>
Compared	O
to	O
gzip	B-Application
compression	I-Application
,	O
JavaScript	O
files	O
compressed	O
with	O
Brotli	B-Application
are	O
roughly	O
15%	O
smaller	O
,	O
HTML	O
files	O
are	O
around	O
20%	O
smaller	O
,	O
and	O
CSS	O
files	O
are	O
around	O
16%	O
smaller	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
introduced	O
support	O
for	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
in	O
version	O
44	O
(	O
released	O
on	O
26	O
January	O
2016	O
)	O
.	O
</s>
<s>
Google	B-Application
Chrome	I-Application
has	O
supported	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
since	O
version	O
50	O
(	O
released	O
on	O
20	O
April	O
2016	O
)	O
.	O
</s>
<s>
Opera	B-Application
has	O
supported	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
since	O
version	O
38	O
(	O
released	O
8	O
June	O
2016	O
)	O
.	O
</s>
<s>
Microsoft	B-Application
Edge	I-Application
has	O
supported	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
since	O
version	O
15	O
(	O
released	O
on	O
5	O
April	O
2017	O
)	O
.	O
</s>
<s>
Safari	B-Application
has	O
supported	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
since	O
version	O
11	O
(	O
released	O
on	O
5	O
October	O
2017	O
)	O
.	O
</s>
<s>
cURL	B-Language
has	O
a	O
compile-time	O
option	O
to	O
support	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
using	O
libbrotli	O
as	O
of	O
version	O
7.57	O
,	O
released	O
on	O
29	O
November	O
2017	O
.	O
</s>
<s>
7zip	B-Language
is	O
available	O
extended	O
with	O
Brotli	B-Application
by	O
7zip-zstd	O
.	O
</s>
<s>
For	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
,	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
has	O
been	O
supported	O
by	O
the	O
mod_brotli	O
module	O
since	O
version	O
2.4.26	O
.	O
</s>
<s>
Microsoft	B-Application
IIS	I-Application
has	O
a	O
supported	O
extension	O
since	O
May	O
2018	O
that	O
adds	O
support	O
for	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
.	O
</s>
<s>
Microsoft	B-Application
Azure	I-Application
Front	I-Application
Door	I-Application
can	O
dynamically	O
compress	O
content	O
on	O
the	O
edge	O
using	O
Brotli	B-Application
since	O
its	O
launch	O
on	O
April	O
17	O
,	O
2019	O
.	O
</s>
<s>
nginx	B-Operating_System
has	O
a	O
ngx_brotli	O
module	O
provided	O
by	O
Google	B-Application
since	O
December	O
2016	O
.	O
</s>
<s>
Node.js	B-Language
features	O
a	O
built-in	O
native	O
en	O
-	O
and	O
decoder	O
since	O
version	O
11.7.0	O
,	O
which	O
can	O
be	O
used	O
to	O
support	O
the	O
"	O
br	O
"	O
content-encoding	O
.	O
</s>
<s>
Amazon	O
CloudFront	O
can	O
automatically	O
compress	O
cacheable	O
responses	O
at	O
the	O
edge	O
using	O
Brotli	B-Application
,	O
as	O
of	O
September	O
2020	O
.	O
</s>
<s>
LiteSpeed	B-Protocol
Web	I-Protocol
Server	I-Protocol
has	O
included	O
the	O
"	O
br	O
"	O
content-encoding	O
method	O
for	O
static	O
files	O
only	O
since	O
version	O
5.2	O
in	O
July	O
2017	O
.	O
</s>
<s>
Cloudflare	B-Application
CDN	O
offers	O
a	O
brotli	B-Application
option	O
to	O
compress	O
data	O
between	O
its	O
edge	O
node	O
and	O
the	O
user	O
.	O
</s>
<s>
Caddy	B-Language
(	O
web	B-Application
server	I-Application
)	O
Serves	O
statically	O
compressed	O
.br	O
files	O
since	O
version	O
0.9.4	O
from	O
December	O
21st	O
,	O
2016	O
.	O
</s>
<s>
lighttpd	B-Protocol
mod_deflate	O
supports	O
.br	O
since	O
1.4.56	O
from	O
November	O
2020	O
.	O
</s>
