<s>
Celery	B-Operating_System
is	O
an	O
open	B-Application
source	I-Application
asynchronous	O
task	O
queue	O
or	O
job	O
queue	O
which	O
is	O
based	O
on	O
distributed	O
message	O
passing	O
.	O
</s>
<s>
The	O
execution	O
units	O
,	O
called	O
tasks	O
,	O
are	O
executed	O
concurrently	O
on	O
one	O
or	O
more	O
worker	O
nodes	O
using	O
multiprocessing	B-Operating_System
,	O
eventlet	O
or	O
gevent	O
.	O
</s>
<s>
Celery	B-Operating_System
is	O
used	O
in	O
production	O
systems	O
,	O
for	O
services	O
such	O
as	O
Instagram	B-Application
,	O
to	O
process	O
millions	O
of	O
tasks	O
every	O
day	O
.	O
</s>
<s>
Celery	B-Operating_System
is	O
written	O
in	O
Python	B-Language
,	O
but	O
the	O
protocol	O
can	O
be	O
implemented	O
in	O
any	O
language	O
.	O
</s>
<s>
It	O
can	O
also	O
operate	O
with	O
other	O
languages	O
using	O
webhooks	B-Protocol
.	O
</s>
<s>
There	O
is	O
also	O
a	O
Ruby-Client	O
called	O
RCelery	O
,	O
a	O
PHP	B-Application
client	O
,	O
a	O
Go	B-Application
client	O
,	O
a	O
Rust	B-Application
client	O
,	O
and	O
a	O
Node.js	B-Language
client	O
.	O
</s>
<s>
The	O
recommended	O
message	B-General_Concept
brokers	I-General_Concept
are	O
RabbitMQ	B-Application
or	O
Redis	B-Operating_System
.	O
</s>
<s>
In	O
comparison	O
with	O
RabbitMQ	B-Application
,	O
Redis	B-Operating_System
represents	O
a	O
good	O
start	O
.	O
</s>
<s>
However	O
,	O
if	O
there	O
is	O
a	O
valid	O
reason	O
and	O
Redis	B-Operating_System
is	O
no	O
longer	O
meeting	O
the	O
requirements	O
for	O
the	O
project	O
,	O
it	O
is	O
simple	O
to	O
switch	O
to	O
RabbitMQ	B-Application
.	O
</s>
<s>
Additionally	O
,	O
MongoDB	B-Application
,	O
Amazon	B-Operating_System
SQS	I-Operating_System
,	O
CouchDB	B-Application
,	O
IronMQ	O
,	O
and	O
databases	O
(	O
using	O
SQLAlchemy	B-Application
or	O
the	O
Django	B-Language
ORM	O
)	O
are	O
supported	O
in	O
status	O
experimental	O
.	O
</s>
