<s>
MessagePack	B-Protocol
is	O
a	O
computer	O
data	O
interchange	O
format	O
.	O
</s>
<s>
It	O
is	O
a	O
binary	O
form	O
for	O
representing	O
simple	O
data	B-General_Concept
structures	I-General_Concept
like	O
arrays	B-Data_Structure
and	O
associative	B-Application
arrays	I-Application
.	O
</s>
<s>
MessagePack	B-Protocol
aims	O
to	O
be	O
as	O
compact	O
and	O
simple	O
as	O
possible	O
.	O
</s>
<s>
The	O
official	O
implementation	O
is	O
available	O
in	O
a	O
variety	O
of	O
languages	O
such	O
as	O
C	B-Language
,	O
C++	B-Language
,	O
C#	B-Application
,	O
D	B-Application
,	O
Erlang	B-Operating_System
,	O
Go	B-Application
,	O
Haskell	B-Language
,	O
Java	B-Language
,	O
JavaScript	B-Language
(	O
NodeJS	B-Language
)	O
,	O
Lua	B-Language
,	O
OCaml	B-Language
,	O
Perl	B-Language
,	O
PHP	B-Application
,	O
Python	B-Language
,	O
Ruby	B-Language
,	O
Scala	B-Application
,	O
Smalltalk	B-Application
,	O
and	O
Swift	B-Application
.	O
</s>
<s>
Data	B-General_Concept
structures	I-General_Concept
processed	O
by	O
MessagePack	B-Protocol
loosely	O
correspond	O
to	O
those	O
used	O
in	O
JSON	B-General_Concept
format	O
.	O
</s>
<s>
MessagePack	B-Protocol
is	O
more	O
compact	O
than	O
JSON	B-General_Concept
,	O
but	O
imposes	O
limitations	O
on	O
array	B-Data_Structure
and	O
integer	O
sizes	O
.	O
</s>
<s>
In	O
JSON	B-General_Concept
,	O
map	O
keys	O
have	O
to	O
be	O
strings	O
,	O
but	O
in	O
MessagePack	B-Protocol
there	O
is	O
no	O
such	O
limitation	O
and	O
any	O
type	O
can	O
be	O
a	O
map	O
key	O
,	O
including	O
types	O
like	O
maps	O
and	O
arrays	B-Data_Structure
,	O
and	O
,	O
like	O
YAML	B-Protocol
,	O
numbers	O
.	O
</s>
<s>
Compared	O
to	O
BSON	B-Protocol
,	O
MessagePack	B-Protocol
is	O
more	O
space-efficient	O
.	O
</s>
<s>
BSON	B-Protocol
is	O
designed	O
for	O
fast	O
in-memory	O
manipulation	O
,	O
whereas	O
MessagePack	B-Protocol
is	O
designed	O
for	O
efficient	O
transmission	O
over	O
the	O
wire	O
.	O
</s>
<s>
For	O
example	O
,	O
BSON	B-Protocol
requires	O
null	O
terminators	O
at	O
the	O
end	O
of	O
all	O
strings	O
and	O
inserts	O
string	O
indexes	O
for	O
list	O
elements	O
,	O
while	O
MessagePack	B-Protocol
does	O
n't	O
.	O
</s>
<s>
BSON	B-Protocol
represents	O
both	O
arrays	B-Data_Structure
and	O
maps	O
internally	O
as	O
documents	O
,	O
which	O
are	O
maps	O
,	O
where	O
an	O
array	B-Data_Structure
is	O
a	O
map	O
with	O
keys	O
as	O
decimal	O
strings	O
counting	O
up	O
from	O
0	O
.	O
</s>
<s>
MessagePack	B-Protocol
on	O
the	O
other	O
hand	O
represents	O
both	O
maps	O
and	O
arrays	B-Data_Structure
as	O
arrays	B-Data_Structure
,	O
where	O
each	O
map	O
key-value	O
pair	O
is	O
contiguous	O
,	O
making	O
odd	O
items	O
keys	O
and	O
even	O
items	O
values	O
.	O
</s>
<s>
The	O
Protocol	B-Protocol
Buffers	I-Protocol
format	O
aims	O
to	O
be	O
compact	O
and	O
is	O
on	O
par	O
with	O
MessagePack	B-Protocol
.	O
</s>
<s>
However	O
,	O
while	O
JSON	B-General_Concept
and	O
MessagePack	B-Protocol
aim	O
to	O
serialize	O
arbitrary	O
data	B-General_Concept
structures	I-General_Concept
with	O
type	O
tags	O
,	O
Protocol	B-Protocol
Buffers	I-Protocol
require	O
a	O
schema	O
to	O
define	O
the	O
data	O
types	O
.	O
</s>
<s>
Protocol	B-Protocol
Buffers	I-Protocol
compiler	O
creates	O
boilerplate	O
code	O
in	O
the	O
target	O
language	O
to	O
facilitate	O
integration	O
of	O
serialization	O
into	O
the	O
application	O
code	O
;	O
MessagePack	B-Protocol
returns	O
only	O
a	O
dynamically	O
typed	O
data	B-General_Concept
structure	I-General_Concept
and	O
provides	O
no	O
automatic	O
structure	O
checks	O
.	O
</s>
<s>
MessagePack	B-Protocol
is	O
referenced	O
in	O
of	O
CBOR	B-Protocol
.	O
</s>
