<s>
Fat-Free	B-Language
Framework	I-Language
is	O
an	O
open-source	B-Application
web	B-Application
framework	I-Application
distributed	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
and	O
hosted	O
by	O
GitHub	B-Application
and	O
SourceForge	B-Application
.	O
</s>
<s>
The	O
source	O
code	O
(	O
~	O
83KB	O
)	O
is	O
written	O
almost	O
entirely	O
in	O
PHP	B-Application
and	O
engineered	O
specifically	O
with	O
user	O
experience	O
and	O
usability	O
as	O
its	O
primary	O
design	O
goals	O
.	O
</s>
<s>
Commonly	O
called	O
F3	O
by	O
PHP	B-Application
developers	O
,	O
Fat-Free	O
was	O
released	O
as	O
free	O
software	O
in	O
2009	O
.	O
</s>
<s>
Its	O
general	O
architecture	O
was	O
influenced	O
by	O
Ruby	B-Language
's	O
Sinatra	B-Application
.	O
</s>
<s>
The	O
base	O
feature	O
set	O
includes	O
a	O
URL	O
router	O
,	O
cache	B-General_Concept
engine	O
,	O
and	O
support	O
for	O
multilingual	O
applications	O
.	O
</s>
<s>
Fat-Free	O
also	O
has	O
a	O
number	O
of	O
plug-ins	B-Application
that	O
extend	O
its	O
functionality	O
as	O
well	O
as	O
data	O
mappers	O
for	O
SQL	B-Language
and	O
NoSQL	B-General_Concept
database	O
back-ends	B-Architecture
:	O
SQLite	B-Language
,	O
MySQL	B-Application
,	O
PostgreSQL	B-Application
,	O
MSSQL	B-Application
,	O
Sybase	B-Application
,	O
DB2	B-Application
,	O
MongoDB	B-Application
,	O
CouchDB	B-Application
,	O
and	O
Flat	B-Application
File	I-Application
.	O
</s>
<s>
The	O
core	O
functionality	O
is	O
accompanied	O
by	O
a	O
number	O
of	O
optional	O
plug-ins	B-Application
,	O
among	O
them	O
a	O
template	B-Application
engine	I-Application
,	O
a	O
Unit	O
testing	O
toolkit	O
,	O
Database-managed	O
sessions	O
,	O
Markdown-to-HTML	O
converter	O
,	O
Atom/RSS	O
feed	O
reader	O
,	O
Image	O
processor	O
,	O
Geodata	B-General_Concept
handler	O
,	O
a	O
Basket/Shopping	O
cart	O
application	O
and	O
data	O
validation	O
.	O
</s>
