<s>
The	O
Caddy	B-Language
web	B-Application
server	I-Application
is	O
an	O
extensible	B-Architecture
,	O
cross-platform	B-Operating_System
,	O
open-source	B-Application
web	B-Application
server	I-Application
written	O
in	O
Go	B-Application
.	O
</s>
<s>
The	O
name	O
"	O
Caddy	B-Language
"	O
refers	O
both	O
to	O
a	O
helper	O
for	O
tedious	O
tasks	O
,	O
and	O
a	O
way	O
to	O
organize	O
multiple	O
parts	O
into	O
a	O
simplified	O
system	O
.	O
</s>
<s>
At	O
its	O
core	O
,	O
Caddy	B-Language
is	O
an	O
extensible	B-Architecture
platform	B-Device
for	O
deploying	O
long-running	O
services	O
(	O
"	O
apps	O
"	O
)	O
using	O
a	O
single	O
,	O
unified	O
configuration	O
that	O
can	O
be	O
updated	O
on-line	O
with	O
a	O
REST	B-Protocol
API	I-Protocol
.	O
</s>
<s>
Official	O
Caddy	B-Language
distributions	O
ship	O
with	O
a	O
set	O
of	O
standard	O
modules	O
which	O
include	O
HTTP	B-Application
server	I-Application
,	O
TLS	B-Protocol
automation	O
,	O
and	O
PKI	B-Architecture
apps	O
.	O
</s>
<s>
It	O
is	O
best	O
known	O
for	O
its	O
automatic	O
HTTPS	B-Protocol
features	O
.	O
</s>
<s>
Matthew	O
Holt	O
initially	O
began	O
solo	O
development	O
on	O
Caddy	B-Language
in	O
2014	O
,	O
followed	O
by	O
the	O
first	O
public	O
release	O
in	O
2015	O
.	O
</s>
<s>
The	O
software	O
soon	O
became	O
a	O
public	O
collaboration	O
with	O
hundreds	O
of	O
contributors	O
on	O
GitHub	B-Application
.	O
</s>
<s>
To	O
satisfy	O
requirements	O
from	O
a	O
growing	O
community	O
with	O
a	O
variety	O
of	O
use	B-Architecture
cases	I-Architecture
,	O
eventually	O
Caddy	B-Language
was	O
completely	O
rewritten	O
from	O
scratch	O
,	O
and	O
a	O
version	O
2.0	O
was	O
released	O
on	O
May	O
4	O
,	O
2020	O
.	O
</s>
<s>
Caddy	B-Language
binaries	O
are	O
officially	O
distributed	O
for	O
Linux	B-Application
,	O
Windows	B-Application
,	O
macOS	B-Application
,	O
BSD	B-Operating_System
,	O
and	O
other	O
operating	B-General_Concept
systems	I-General_Concept
on	O
a	O
variety	O
of	O
architectures	B-General_Concept
including	O
x86-64	B-Device
,	O
ARM	B-Architecture
,	O
MIPS	B-Device
,	O
S390X	B-Device
,	O
and	O
PPC64	B-General_Concept
.	O
</s>
<s>
Official	O
distributions	O
of	O
32-bit	O
binaries	O
were	O
discontinued	O
,	O
but	O
Caddy	B-Language
can	O
be	O
compiled	B-Language
from	O
source	O
for	O
IA-32	B-Device
architectures	B-General_Concept
.	O
</s>
<s>
Packages	O
for	O
Debian	O
,	O
CentOS	O
,	O
RedHat	O
,	O
and	O
Arch	O
Linux	B-Application
are	O
also	O
maintained	O
,	O
as	O
well	O
as	O
an	O
official	O
Docker	B-Language
image	O
.	O
</s>
<s>
The	O
architecture	O
of	O
Caddy	B-Language
is	O
organized	O
into	O
three	O
main	O
components	O
:	O
a	O
command	B-Application
,	O
the	O
core	O
library	B-Library
,	O
and	O
configuration	O
modules	O
.	O
</s>
<s>
The	O
command	B-Application
is	O
the	O
extensible	B-Architecture
interface	O
by	O
which	O
the	O
program	B-Application
is	O
executed	O
;	O
it	O
can	O
also	O
load	O
configuration	B-Protocol
files	I-Protocol
,	O
run	O
common	O
modes	O
,	O
manage	O
installed	O
plugins	O
,	O
and	O
offer	O
relevant	O
utility	O
functions	O
.	O
</s>
<s>
The	O
core	O
library	B-Library
has	O
APIs	B-General_Concept
for	O
loading	O
,	O
unloading	O
,	O
and	O
managing	B-General_Concept
configuration	I-General_Concept
;	O
but	O
it	O
does	O
nothing	O
particularly	O
useful	O
on	O
its	O
own	O
.	O
</s>
<s>
Most	O
of	O
Caddy	B-Language
's	O
functionality	O
is	O
provided	O
by	O
,	O
which	O
are	O
plugins	O
that	O
extend	O
Caddy	B-Language
's	O
configuration	O
structure	O
;	O
for	O
example	O
,	O
the	O
HTTP	B-Application
server	I-Application
is	O
a	O
module	O
.	O
</s>
<s>
Caddy	B-Language
modules	O
implement	O
various	O
long-running	O
services	O
,	O
web	O
standards	O
,	O
and	O
other	O
useful	O
features	O
.	O
</s>
<s>
Caddy	B-Language
's	O
input	O
is	O
a	O
JSON	B-General_Concept
configuration	O
document	O
which	O
is	O
received	O
through	O
an	O
open	O
socket	O
via	O
a	O
RESTful	B-Protocol
HTTP	B-Protocol
API	B-General_Concept
.	O
</s>
<s>
In	O
the	O
absence	O
of	O
an	O
HTTP	B-Protocol
client	O
,	O
Caddy	B-Language
's	O
command-line	B-Application
interface	I-Application
can	O
be	O
used	O
to	O
load	O
configuration	B-Protocol
files	I-Protocol
.	O
</s>
<s>
Config	O
adapters	O
may	O
be	O
used	O
to	O
convert	O
other	O
configuration	O
formats	O
to	O
JSON	B-General_Concept
.	O
</s>
<s>
Existing	O
adapters	O
include	O
the	O
Caddyfile	O
,	O
which	O
has	O
first-class	O
support	O
in	O
the	O
command	B-Application
line	I-Application
;	O
and	O
YAML	B-Protocol
,	O
TOML	B-Protocol
,	O
Nginx	B-Operating_System
,	O
and	O
several	O
other	O
formats	O
.	O
</s>
<s>
When	O
a	O
configuration	O
is	O
received	O
through	O
its	O
administration	O
socket	O
,	O
Caddy	B-Language
decodes	O
the	O
configuration	O
for	O
all	O
the	O
specified	O
modules	O
,	O
and	O
starts	O
running	O
all	O
the	O
app	O
modules	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
HTTP	B-Application
server	I-Application
is	O
an	O
app	O
module	O
which	O
uses	O
HTTP	B-Protocol
handler	O
modules	O
to	O
handle	O
HTTP	B-Protocol
requests	I-Protocol
;	O
these	O
handlers	O
might	O
use	O
yet	O
other	O
modules	O
to	O
implement	O
their	O
functionality	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
Plugins	O
are	O
installed	O
by	O
statically	O
compiling	B-Language
them	O
directly	O
into	O
the	O
Caddy	B-Language
binary	O
.	O
</s>
<s>
Without	O
plugins	O
,	O
Caddy	B-Language
's	O
native	O
configuration	O
structure	O
only	O
has	O
some	O
basic	O
options	O
for	O
administration	O
and	O
logging	O
.	O
</s>
<s>
Official	O
Caddy	B-Language
distributions	O
ship	O
with	O
dozens	O
of	O
standard	O
modules	O
;	O
others	O
can	O
be	O
added	O
from	O
the	O
project	O
's	O
website	O
,	O
using	O
the	O
,	O
or	O
by	O
manually	O
compiling	B-Language
a	O
custom	O
build	O
.	O
</s>
<s>
The	O
is	O
an	O
app	O
module	O
that	O
comes	O
standard	O
with	O
official	O
Caddy	B-Language
distributions	O
.	O
</s>
<s>
It	O
is	O
primarily	O
used	O
as	O
a	O
static	O
file	O
server	B-Application
and	O
load-balancing	O
reverse	B-General_Concept
proxy	I-General_Concept
.	O
</s>
<s>
While	O
the	O
basis	O
of	O
Caddy	B-Language
's	O
HTTP	B-Protocol
features	O
use	O
the	O
implementation	O
found	O
in	O
Go	B-Application
's	O
standard	O
library	B-Library
,	O
a	O
variety	O
enhancements	O
and	O
customizations	O
are	O
available	O
as	O
middleware	B-General_Concept
and	O
exposed	O
through	O
configuration	O
parameters	O
:	O
</s>
<s>
Caddy	B-Language
's	O
HTTP	B-Application
server	I-Application
handles	O
requests	O
according	O
to	O
configured	O
routes	O
in	O
a	O
middleware	B-General_Concept
pattern	O
.	O
</s>
<s>
Routes	O
are	O
defined	O
in	O
a	O
list	O
,	O
and	O
each	O
route	O
that	O
matches	O
the	O
request	O
is	O
applied	O
to	O
the	O
middleware	B-General_Concept
chain	O
in	O
order	O
.	O
</s>
<s>
Requests	O
can	O
be	O
matched	O
from	O
a	O
variety	O
of	O
parameters	O
including	O
HTTP	B-Protocol
method	O
,	O
hostname	B-Protocol
,	O
remote	O
address	O
,	O
header	O
fields	O
,	O
path	O
,	O
query	O
string	O
,	O
protocol	O
,	O
variable	O
values	O
,	O
file	O
existence	O
,	O
CEL	O
expressions	O
,	O
and	O
others	O
as	O
given	O
by	O
plugins	O
.	O
</s>
<s>
Once	O
matched	O
,	O
handler	O
modules	O
are	O
invoked	O
,	O
which	O
may	O
include	O
a	O
file	O
server	B-Application
,	O
a	O
rewrite	O
middleware	B-General_Concept
,	O
the	O
reverse	B-General_Concept
proxy	I-General_Concept
,	O
rate	O
limiting	O
,	O
header	O
manipulation	O
,	O
and	O
template	O
rendering	O
,	O
among	O
other	O
functions	O
.	O
</s>
<s>
By	O
default	O
,	O
TLS	B-Protocol
is	O
used	O
automatically	O
if	O
any	O
routes	O
have	O
a	O
non-empty	O
host	O
matcher	O
.	O
</s>
<s>
These	O
are	O
assumed	O
to	O
be	O
site	O
names	O
or	O
IP	B-Protocol
addresses	I-Protocol
that	O
Caddy	B-Language
is	O
serving	O
,	O
so	O
Caddy	B-Language
will	O
automatically	O
procure	O
and	O
renew	O
certificates	O
for	O
the	O
configured	O
hostnames	B-Protocol
and	O
IP	B-Protocol
addresses	I-Protocol
.	O
</s>
<s>
When	O
automatic	O
HTTPS	B-Protocol
is	O
activated	O
in	O
this	O
manner	O
,	O
Caddy	B-Language
will	O
also	O
redirect	O
HTTP	B-Protocol
requests	I-Protocol
to	O
their	O
equivalent	O
HTTPS	B-Protocol
location	O
.	O
</s>
<s>
The	O
comes	O
standard	O
with	O
official	O
Caddy	B-Language
distributions	O
.	O
</s>
<s>
It	O
acts	O
as	O
a	O
TLS	B-Protocol
server	B-Application
and	O
is	O
designed	O
for	O
automation	O
.	O
</s>
<s>
Caddy	B-Language
's	O
TLS	B-Protocol
defaults	O
are	O
considered	O
safe	O
and	O
modern	O
.	O
</s>
<s>
In	O
terms	O
of	O
securing	O
private	B-Application
keys	I-Application
,	O
Caddy	B-Language
is	O
not	O
vulnerable	O
to	O
memory	O
safety	O
vulnerabilities	O
such	O
as	O
Heartbleed	O
because	O
it	O
is	O
written	O
in	O
Go	B-Application
.	O
</s>
<s>
One	O
of	O
the	O
primary	O
purposes	O
of	O
this	O
module	O
is	O
to	O
load	O
TLS	B-Protocol
certificates	O
into	O
memory	O
so	O
they	O
can	O
be	O
served	O
to	O
complete	O
TLS	B-Protocol
handshakes	O
.	O
</s>
<s>
Certificate	O
and	O
key	O
files	O
may	O
be	O
loaded	O
manually	O
into	O
the	O
server	B-Application
,	O
but	O
they	O
are	O
usually	O
automated	O
by	O
specifying	O
subject	O
names	O
.	O
</s>
<s>
If	O
loaded	O
manually	O
,	O
Caddy	B-Language
does	O
not	O
auto-renew	O
them	O
.	O
</s>
<s>
A	O
given	O
certificate	O
will	O
be	O
automated	O
according	O
to	O
the	O
first	O
matching	O
automation	O
policy	O
for	O
its	O
subject	O
name	O
(	O
typically	O
a	O
domain	O
name	O
or	O
IP	B-Protocol
address	I-Protocol
)	O
.	O
</s>
<s>
An	O
automation	O
policy	O
consists	O
of	O
issuers	O
and	O
various	O
certificate	O
and	O
management	O
options	O
such	O
as	O
key	O
type	O
,	O
where	O
to	O
store	O
the	O
certificate	O
,	O
whether	O
to	O
manage	O
the	O
certificate	O
"	O
on-demand	O
"	O
,	O
and	O
OCSP	B-Protocol
options	O
.	O
</s>
<s>
These	O
automation	O
features	O
work	O
for	O
server	B-Application
certificates	O
as	O
well	O
as	O
client	O
certificates	O
.	O
</s>
<s>
An	O
issuer	O
is	O
a	O
source	O
for	O
a	O
certificate	O
,	O
and	O
is	O
typically	O
an	O
ACME	B-Protocol
certificate	B-Architecture
authority	I-Architecture
.	O
</s>
<s>
Caddy	B-Language
fully	O
supports	O
the	O
ACME	B-Protocol
protocol	I-Protocol
including	O
the	O
HTTP	B-Protocol
,	O
TLS-ALPN	O
,	O
and	O
DNS	O
challenges	O
,	O
External	O
Account	O
Binding	O
(	O
EAB	O
)	O
,	O
multiple	O
certificate	O
chains	O
,	O
and	O
smart	O
retry	O
heuristics	O
.	O
</s>
<s>
Caddy	B-Language
can	O
also	O
be	O
its	O
own	O
issuer	O
with	O
its	O
embedded	O
PKI	B-Architecture
facilities	O
.	O
</s>
<s>
TLS	B-Protocol
certificates	O
can	O
be	O
stored	O
in	O
a	O
configurable	O
storage	O
backend	O
,	O
which	O
is	O
by	O
default	O
the	O
local	O
file	O
system	O
.	O
</s>
<s>
Caddy	B-Language
instances	O
which	O
are	O
configured	O
to	O
use	O
the	O
same	O
storage	O
backend	O
will	O
automatically	O
act	O
as	O
part	O
of	O
a	O
cluster	B-Architecture
and	O
share	O
certificate	O
and	O
OCSP	B-Protocol
assets	O
,	O
including	O
coordinating	O
the	O
obtaining	O
and	O
renewal	O
of	O
certificates	O
.	O
</s>
<s>
However	O
,	O
Caddy	B-Language
supports	O
a	O
mode	O
of	O
automation	O
called	O
which	O
defers	O
certificate	O
operations	O
until	O
the	O
very	O
moment	O
the	O
certificate	O
is	O
needed	O
,	O
during	O
the	O
TLS	B-Protocol
handshake	O
.	O
</s>
<s>
This	O
is	O
suitable	O
for	O
use	B-Architecture
cases	I-Architecture
where	O
the	O
site	O
owner	O
does	O
not	O
control	O
the	O
domain	O
names	O
served	O
by	O
the	O
server	B-Application
.	O
</s>
<s>
In	O
order	O
to	O
be	O
safe	O
from	O
abuse	O
on	O
a	O
public	O
network	O
,	O
the	O
site	O
owner	O
should	O
configure	O
an	O
endpoint	O
that	O
Caddy	B-Language
will	O
query	O
to	O
ask	O
if	O
a	O
certificate	O
may	O
be	O
obtained	O
for	O
the	O
given	O
Server	B-Application
Name	O
Indication	O
(	O
SNI	O
)	O
in	O
the	O
handshake	O
.	O
</s>
<s>
Caddy	B-Language
implements	O
OCSP	B-Protocol
stapling	O
by	O
default	O
.	O
</s>
<s>
All	O
loaded	O
certificates	O
which	O
specify	O
an	O
OCSP	B-Protocol
responder	O
in	O
the	O
Authority	O
Information	O
Access	O
extension	O
will	O
have	O
their	O
OCSP	B-Protocol
response	O
stapled	O
,	O
cached	O
,	O
and	O
refreshed	O
automatically	O
as	O
needed	O
.	O
</s>
<s>
If	O
an	O
OCSP	B-Protocol
response	O
indicates	O
a	O
status	O
of	O
Revoked	O
for	O
a	O
managed	O
certificate	O
,	O
Caddy	B-Language
will	O
automatically	O
attempt	O
to	O
replace	O
the	O
certificate	O
with	O
a	O
new	O
one	O
.	O
</s>
<s>
When	O
serving	O
TLS	B-Protocol
,	O
Caddy	B-Language
will	O
automatically	O
rotate	O
session	O
ticket	O
keys	O
periodically	O
to	O
help	O
preserve	O
perfect	O
forward	O
secrecy	O
.	O
</s>
<s>
These	O
keys	O
can	O
also	O
be	O
stored	O
in	O
a	O
configurable	O
backend	O
and	O
used	O
by	O
a	O
cluster	B-Architecture
of	O
instances	O
for	O
improved	O
performance	O
in	O
a	O
distributed	O
fashion	O
.	O
</s>
<s>
The	O
comes	O
standard	O
with	O
official	O
Caddy	B-Language
distributions	O
.	O
</s>
<s>
Its	O
primary	O
purpose	O
is	O
to	O
manage	O
certificate	B-Architecture
authorities	I-Architecture
(	O
CAs	O
)	O
that	O
can	O
sign	O
certificates	O
.	O
</s>
<s>
Each	O
CA	O
consists	O
of	O
a	O
root	O
and	O
intermediate	O
key	B-Application
pair	I-Application
,	O
which	O
are	O
persisted	O
to	O
storage	O
.	O
</s>
<s>
Until	O
2016	O
,	O
Caddy	B-Language
operated	O
completely	O
by	O
volunteer	O
effort	O
without	O
any	O
financial	O
support	O
,	O
simply	O
accepting	O
occasional	O
donations	O
from	O
the	O
website	O
.	O
</s>
<s>
Light	O
Code	O
Labs	O
,	O
LLC	O
was	O
formed	O
to	O
become	O
the	O
legal	O
entity	O
behind	O
Caddy	B-Language
.	O
</s>
<s>
With	O
legal	O
legitimacy	O
,	O
the	O
first	O
form	O
of	O
financial	O
support	O
came	O
from	O
a	O
Mozilla	B-Operating_System
Open	O
Source	O
Support	O
(	O
MOSS	O
)	O
program	B-Application
award	O
in	O
2016	O
.	O
</s>
<s>
This	O
provided	O
funding	O
for	O
6	O
months	O
of	O
development	O
work	O
,	O
and	O
was	O
crucial	O
to	O
Caddy	B-Language
's	O
growth	O
at	O
that	O
stage	O
.	O
</s>
<s>
With	O
only	O
little	O
success	O
,	O
it	O
was	O
decided	O
that	O
phasing	O
out	O
those	O
products	O
in	O
favor	O
of	O
distributing	O
official	O
binaries	O
intended	O
for	O
commercial	O
use	O
under	O
a	O
proprietary	O
license	O
could	O
increase	O
sustainability	O
by	O
requiring	O
companies	O
to	O
pay	O
for	O
the	O
right	O
to	O
use	O
specially-offered	O
,	O
pre-compiled	O
Caddy	B-Language
binaries	O
that	O
powered	O
their	O
business	O
.	O
</s>
<s>
This	O
would	O
leave	O
Caddy	B-Language
's	O
source	O
code	O
under	O
the	O
Apache	B-Application
license	I-Application
for	O
anyone	O
to	O
use	O
freely	O
,	O
while	O
still	O
being	O
able	O
to	O
gain	O
some	O
financial	O
backing	O
from	O
able	O
companies	O
as	O
customers	O
.	O
</s>
<s>
In	O
2019	O
,	O
Light	O
Code	O
Labs	O
entered	O
into	O
a	O
partnership	O
with	O
Ardan	O
Studios	O
to	O
design	O
and	O
build	O
an	O
all-new	O
version	O
of	O
Caddy	B-Language
which	O
could	O
be	O
utilized	O
more	O
readily	O
in	O
enterprise	O
environments	O
:	O
Caddy	B-Language
Enterprise	O
.	O
</s>
<s>
reaffirming	O
that	O
Caddy	B-Language
will	O
continue	O
to	O
be	O
,	O
and	O
always	O
has	O
been	O
,	O
an	O
Apache-licensed	B-Application
open	O
source	O
project	O
,	O
</s>
<s>
dropping	O
all	O
proprietary	O
licensing	O
and	O
removing	O
the	O
business	O
use	B-Architecture
case	I-Architecture
restrictions	O
from	O
official	O
binaries	O
,	O
</s>
<s>
rebranding	O
the	O
new	O
version	O
of	O
Caddy	B-Language
simply	O
as	O
Caddy	B-Language
2	O
,	O
</s>
<s>
Ardan	O
Studios	O
would	O
proceed	O
to	O
offer	O
professional	O
training	O
,	O
Caddy	B-Language
development	O
,	O
and	O
enterprise	O
support	O
to	O
businesses	O
,	O
and	O
provided	O
funding	O
for	O
full-time	O
open	O
source	O
development	O
of	O
the	O
Caddy	B-Language
project	O
for	O
almost	O
one	O
year	O
.	O
</s>
<s>
Shortly	O
before	O
the	O
initial	O
release	O
of	O
Caddy	B-Language
2	O
,	O
an	O
agreement	O
was	O
signed	O
by	O
Light	O
Code	O
Labs	O
and	O
Ardan	O
Studios	O
for	O
the	O
Caddy	B-Language
project	O
(	O
along	O
with	O
,	O
Caddy	B-Language
's	O
core	O
TLS	B-Protocol
automation	O
library	B-Library
)	O
to	O
be	O
acquired	O
by	O
API	B-General_Concept
Layer	O
,	O
GmbH	O
(	O
later	O
Stack	O
Holdings	O
,	O
GmbH	O
)	O
.	O
</s>
<s>
As	O
of	O
2021	O
,	O
necessary	O
financial	O
support	O
for	O
the	O
Caddy	B-Language
project	O
continues	O
by	O
sponsorships	O
through	O
GitHub	B-Application
Sponsors	O
,	O
with	O
ZeroSSL	O
(	O
a	O
Stack	O
Holdings	O
company	O
)	O
being	O
the	O
primary	O
,	O
executive	O
sponsor	O
.	O
</s>
<s>
Caddy	B-Language
has	O
been	O
used	O
as	O
the	O
basis	O
for	O
other	O
software	O
projects	O
and	O
commercial	O
services	O
,	O
and	O
its	O
reach	O
extends	O
into	O
academic	O
research	O
and	O
industry	O
discussion	O
.	O
</s>
<s>
CoreDNS	O
was	O
created	O
by	O
Miek	O
Gieben	O
from	O
a	O
fork	O
of	O
Caddy	B-Language
v1	O
which	O
was	O
modified	O
to	O
serve	O
DNS	O
instead	O
of	O
HTTPS	B-Protocol
.	O
</s>
<s>
It	O
leveraged	O
Caddy	B-Language
's	O
Caddyfile	O
configuration	O
format	O
,	O
plugin	O
architecture	O
,	O
and	O
use	O
of	O
the	O
Go	B-Application
language	I-Application
.	O
</s>
<s>
Cloudflare	B-Application
implemented	O
a	O
machine-in-the-middle	O
(	O
MITM	O
)	O
detection	O
service	O
originally	O
based	O
on	O
Caddy	B-Language
using	O
its	O
native	O
MITM	O
detection	O
capabilities	O
.	O
</s>
<s>
The	O
same	O
company	O
also	O
used	O
Caddy	B-Language
to	O
serve	O
an	O
experimental	O
TLS	B-Protocol
1.3	O
implementation	O
while	O
participating	O
in	O
the	O
formation	O
of	O
the	O
final	O
TLS	B-Protocol
1.3	O
specification	O
.	O
</s>
<s>
Let	B-Application
's	I-Application
Encrypt	I-Application
considers	O
Caddy	B-Language
's	O
implementation	O
of	O
ACME	B-Protocol
to	O
be	O
the	O
gold	O
standard	O
of	O
ACME	B-Protocol
clients	O
,	O
and	O
Caddy	B-Language
has	O
become	O
a	O
model	O
for	O
similar	O
software	O
to	O
follow	O
.	O
</s>
<s>
Caddy	B-Language
has	O
participated	O
in	O
a	O
number	O
of	O
academic	O
papers	O
and	O
enabled	O
various	O
Internet	O
research	O
.	O
</s>
<s>
validating	O
the	O
feasibility	O
of	O
the	O
ACME	B-Protocol
protocol	I-Protocol
in	O
production	O
servers	O
,	O
</s>
<s>
Internet-scale	O
deployment	O
of	O
QUIC	B-Protocol
,	O
</s>
<s>
measuring	O
the	O
security	O
harm	O
of	O
TLS	B-Protocol
cryptography	O
shortcuts	O
,	O
</s>
<s>
advocating	O
the	O
case	O
for	O
secure-by-default	O
TLS	B-Protocol
,	O
</s>
<s>
and	O
improving	O
the	O
usability	O
of	O
deploying	O
HTTPS	B-Protocol
.	O
</s>
