website/content/docs/channel-modes.md

Channel modes

Set with MODE <#channel> +<mode> [param]. Modes are grouped by the four CHANMODES types the server advertises in ISUPPORT: A (list modes, always take a parameter), B (always take a parameter), C (parameter only when set), D (flag, no parameter). Membership prefixes are listed at the end.

Type A — list modes

Each takes a parameter; using it with no parameter queries the list.

Mode	Name	Description
b	ban	Ban a matching nick!user@host or extban from the channel
e	ban exception	Exempt a matching mask from bans
I	invite exception	A matching mask may join a +i channel without an invite
g	spamfilter	Per-channel message word/glob filters (matches message text)
X	exemptchanops	<restriction>:<rankchar> — exempt members at/above a rank from a named restriction
w	autoop	<prefixchar>:<hostmask> — auto-grant a status prefix on join

Type B — always take a parameter

Mode	Name	Description
k	key	Channel password required to join

Type C — parameter only when set

Mode	Name	Param	Description
l	limit	<n>	Maximum member count
f	message flood	[*]<lines>:<secs>	Kick a user exceeding the rate; leading * also bans
j	join flood	<joins>:<secs>	Lock new joins for 60s after the threshold
F	nick flood	<changes>:<secs>	Block nick changes for 60s after the threshold
L	redirect	<#target>	Send joiners to another channel when +l-full
H	history	<lines>[:<secs>]	Replay recent messages to joiners
B	anticaps	<1..100>	Reject messages that are ≥ this % uppercase (ops exempt)
J	kicknorejoin	<secs>	Block rejoin for N seconds after a kick
d	delaymsg	<secs>	New members can't speak for N seconds (voiced+ exempt)
K	norepeat	<n>	Block a message identical to one of the sender's previous N lines

Type D — flag modes

Mode	Name	Description
A	allowinvite	Any member may use INVITE
C	noctcp	Block CTCPs to the channel
D	delayjoin	Hide joining members until they speak or gain a prefix
G	censor	Apply the network word censor to messages
M	regmoderated	Only registered (logged-in) users may speak
N	nonick	Block nick changes by members while in the channel
O	operonly	Only IRC operators may join (oper-set)
P	permanent	Channel persists with no members (oper-set)
Q	nokicks	Block KICK in the channel
R	regonly	Only registered users may join
S	stripcolor	Strip mIRC colour/formatting from messages
T	nonotice	Block NOTICEs to the channel
U	opmoderated	Messages from unprivileged users go only to ops
c	nocolor	Block messages containing colour/formatting
i	inviteonly	Require an invite (or +I match) to join
m	moderated	Only voiced+ may speak
n	noexternal	Block messages from users not in the channel
p	private	Private channel
r	registered	Registered channel — set only by services
s	secret	Secret channel (hidden from LIST/WHOIS)
t	topiclock	Only ops may change the topic
z	secureonly	Only TLS users may join (settable only when all members are on TLS)

Prefix / status modes

Take a nick parameter; ordered high → low rank. Sigils and the ranks required to grant/revoke are configurable via customprefix.

Mode	Prefix	Name	Rank
y	!	oper prefix (network staff)	60
q	~	owner / founder	50
a	&	admin / protected	40
o	@	op	30
h	%	halfop	20
v	+	voice	10

The ! oper prefix only exists when operprefix or ojoin is enabled. Granting or removing a prefix requires out-ranking both the configured set/unset rank and the target's current top rank.