Channels

Channel Basics

Channels are virtual spaces where users can chat. A channel name must start with a prefix character:

Prefix	Type	Default join limit
`#`	Standard (public) channel	20 per user
`&`	Local channel	5 per user

Channel names may contain letters (a-z, A-Z), digits (0-9), underscores (_), and hyphens (-). The maximum name length is 64 characters (excluding the prefix), configurable via max_channel_name_length.

Examples of valid channel names: #general, #my-project, &local-chat

Channel Creation

A channel is created automatically when the first user joins it. That user becomes the channel operator (+o) automatically.

If the channel is registered with ChanServ, the founder’s privileges and settings are applied when the channel is (re)created.

Channel Limits

Limit	Default	Config key
`#` channels per user	20	`channel_join_limits: %{"#" => 20}`
`&` channels per user	5	`channel_join_limits: %{"&" => 5}`
Max name length	64	`max_channel_name_length`
Max topic length	300	`max_topic_length`
Max kick message	255	`max_kick_message_length`
Max modes per MODE command	20	`max_modes_per_command`
Max ban entries (+b)	100	`max_list_entries: %{"b" => 100}`

Channel Modes Overview

Mode	Name	Description
`+b`	Ban	Prevents matching users from joining
`+C`	No CTCP	Blocks CTCP messages
`+c`	No Colors	Blocks messages with IRC color codes
`+d`	Delay Message	Users must wait N seconds before speaking after joining
`+e`	Ban Exception	Exempts matching users from +b bans
`+i`	Invite Only	Only invited users (or those matching +I) can join
`+I`	Invite Exception	Exempts from +i invite requirement
`+j`	Join Throttle	Limits join rate (`joins:seconds` format)
`+k`	Key	Requires a password to join
`+l`	Limit	Maximum number of users allowed
`+m`	Moderated	Only voiced/opped users can speak
`+M`	Registered Only Speak	Only registered users may speak
`+n`	No External Messages	Messages only from users in the channel
`+O`	Oper Only	Only IRC operators may join
`+o`	Operator	Channel operator privileges (per-user)
`+p`	Private	Hidden from LIST (but shown in WHOIS)
`+r`	Registered	Channel is registered with ChanServ
`+R`	Registered Only Join	Only registered users may join
`+s`	Secret	Hidden from LIST and WHOIS
`+t`	Topic Lock	Only ops can set the topic
`+T`	No NOTICEs	Blocks NOTICE messages in the channel
`+u`	Auditorium	Hides join/part/quit from non-voiced users
`+v`	Voice	Can speak in moderated channels (per-user)
`+z`	Secure Only	Only users with SSL/TLS (+Z) may join

See Channel Modes for complete details on each mode.

Topic

The channel topic is set with /topic #channel New topic here. Rules:

Maximum length: 300 characters (configurable)
When +t is set, only channel operators can change the topic
When a channel is registered with ChanServ and KEEPTOPIC is enabled (default), the topic is restored when the channel is re-created after becoming empty

Bans

Bans (+b) use IRC mask format: nick!ident@hostname. Wildcards * and ? are supported.

+b *!*@192.168.1.100          # Ban by IP
+b BadUser!*@*                # Ban by nick
+b *!badident@*               # Ban by ident
+b *!*@*.spammer.net          # Ban by hostname pattern

Ban exceptions (+e) override bans for matching users. A user matching both a ban and an exception is allowed in.

Invite exceptions (+I) allow users matching the mask to join invite-only (+i) channels without an explicit invite.

Join Throttle (+j)

Join throttle format: N:T where N = max joins allowed per T seconds.

+j 5:60     # Maximum 5 joins per 60 seconds
+j 3:10     # Maximum 3 joins per 10 seconds

IRC operators bypass join throttle restrictions.

Auditorium Mode (+u)

When +u (Auditorium) is set:

Users with voice (+v) or higher can see join/part/quit messages normally
Regular users do not see join/part/quit messages from other regular users
This is useful for large channels or announcement-style rooms

Delay Message (+d)

When +d N is set, users must wait N seconds after joining before they can send messages. This helps prevent join floods.

The +r (Registered) Channel Mode

When a channel is registered with ChanServ, the +r mode is set by the server. This is informational — it tells users the channel has a registered owner.

Channel User Privileges

Within a channel, users can have privilege modes:

Symbol	Mode	Description
`@`	`+o` (Operator)	Full channel management: kick, ban, set modes, change topic
`+`	`+v` (Voice)	Can speak in moderated (`+m`) channels

The first user to join a channel automatically receives +o. Channel operators can grant or remove these modes.