<s>
MetaMask	B-Protocol
is	O
a	O
software	O
cryptocurrency	B-Protocol
wallet	I-Protocol
used	O
to	O
interact	O
with	O
the	O
Ethereum	B-Application
blockchain	B-Application
.	O
</s>
<s>
It	O
allows	O
users	O
to	O
access	O
their	O
Ethereum	B-Application
wallet	O
through	O
a	O
browser	B-Protocol
extension	I-Protocol
or	O
mobile	B-Application
app	I-Application
,	O
which	O
can	O
then	O
be	O
used	O
to	O
interact	O
with	O
decentralized	B-Application
applications	I-Application
.	O
</s>
<s>
MetaMask	B-Protocol
is	O
developed	O
by	O
ConsenSys	O
Software	O
Inc.	O
,	O
a	O
blockchain	B-Application
software	O
company	O
focusing	O
on	O
Ethereum-based	O
tools	O
and	O
infrastructure	O
.	O
</s>
<s>
MetaMask	B-Protocol
allows	O
users	O
to	O
store	O
and	O
manage	O
account	O
keys	O
,	O
broadcast	O
transactions	O
,	O
send	O
and	O
receive	O
Ethereum-based	O
cryptocurrencies	O
and	O
tokens	O
,	O
and	O
securely	O
connect	O
to	O
decentralized	B-Application
applications	I-Application
through	O
a	O
compatible	O
web	B-Application
browser	I-Application
or	O
the	O
mobile	B-Application
app	I-Application
's	O
built-in	O
browser	B-Application
.	O
</s>
<s>
Websites	O
or	O
other	O
decentralized	B-Application
applications	I-Application
are	O
able	O
to	O
connect	O
,	O
authenticate	O
,	O
and/or	O
integrate	O
other	O
smart	B-Application
contract	I-Application
functionality	O
with	O
a	O
user	O
's	O
MetaMask	B-Protocol
wallet	O
(	O
and	O
any	O
other	O
similar	O
blockchain	B-Application
wallet	O
browser	B-Protocol
extensions	I-Protocol
)	O
via	O
JavaScript	B-Language
code	O
that	O
allows	O
the	O
website	O
to	O
send	O
action	O
prompts	O
,	O
signature	O
requests	O
,	O
or	O
transaction	O
requests	O
to	O
the	O
user	O
through	O
MetaMask	B-Protocol
as	O
an	O
intermediary	O
.	O
</s>
<s>
The	O
application	O
includes	O
an	O
integrated	O
service	O
for	O
exchanging	O
Ethereum	B-Application
tokens	O
by	O
aggregating	O
several	O
decentralized	O
exchanges	O
(	O
DEXs	O
)	O
to	O
find	O
the	O
best	O
exchange	O
rate	O
.	O
</s>
<s>
This	O
feature	O
,	O
branded	O
as	O
MetaMask	B-Protocol
Swaps	O
,	O
charges	O
a	O
service	O
fee	O
of	O
0.875	O
%	O
of	O
the	O
transaction	O
amount	O
.	O
</s>
<s>
,	O
MetaMask	B-Protocol
's	O
browser	B-Protocol
extension	I-Protocol
had	O
over	O
21	O
million	O
monthly	O
active	O
users	O
,	O
according	O
to	O
Bloomberg	O
.	O
</s>
<s>
MetaMask	B-Protocol
was	O
created	O
by	O
ConsenSys	O
in	O
2016	O
.	O
</s>
<s>
Prior	O
to	O
2019	O
,	O
MetaMask	B-Protocol
had	O
only	O
been	O
available	O
as	O
a	O
desktop	O
browser	B-Protocol
extension	I-Protocol
for	O
Google	B-Application
Chrome	I-Application
and	O
Firefox	B-Application
browsers	I-Application
.	O
</s>
<s>
Given	O
the	O
popularity	O
of	O
MetaMask	B-Protocol
among	O
cryptocurrency	O
users	O
,	O
and	O
its	O
lack	O
of	O
an	O
official	O
mobile	B-Application
app	I-Application
for	O
several	O
years	O
,	O
instances	O
of	O
malicious	O
software	O
posing	O
as	O
MetaMask	B-Protocol
became	O
problematic	O
for	O
Google	B-Application
in	O
regulating	O
its	O
Chrome	B-Application
Web	I-Application
Store	I-Application
and	O
Google	B-Application
Play	I-Application
platforms	O
.	O
</s>
<s>
In	O
one	O
instance	O
,	O
Google	B-Application
Play	I-Application
unintentionally	O
removed	O
MetaMask	B-Protocol
's	O
official	O
beta	O
app	O
before	O
reverting	O
the	O
decision	O
a	O
week	O
later	O
on	O
January	O
1	O
,	O
2020	O
.	O
</s>
<s>
Starting	O
in	O
2019	O
,	O
MetaMask	B-Protocol
began	O
releasing	O
mobile	B-Application
app	I-Application
versions	O
for	O
closed	O
beta	O
testing	O
,	O
followed	O
by	O
their	O
official	O
public	O
release	O
for	O
iOS	B-Application
and	O
Android	B-Application
in	O
September	O
2020	O
.	O
</s>
<s>
During	O
October	O
2020	O
,	O
MetaMask	B-Protocol
Swaps	O
,	O
a	O
built-in	O
DEX	O
aggregation	O
service	O
was	O
added	O
to	O
the	O
desktop	O
extension	O
.	O
</s>
<s>
While	O
MetaMask	B-Protocol
and	O
other	O
"	O
Web3	O
"	O
focused	O
applications	O
aim	O
to	O
decentralize	O
control	O
over	O
personal	O
data	O
and	O
increase	O
user	O
privacy	O
,	O
critics	O
have	O
pointed	O
to	O
the	O
potential	O
for	O
MetaMask	B-Protocol
's	O
browser	B-Protocol
extension	I-Protocol
to	O
leak	O
identifiable	O
information	O
to	O
data	O
collection	O
networks	O
and	O
web	B-Application
trackers	I-Application
as	O
a	O
fundamental	O
flaw	O
.	O
</s>
