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content/docs/ircv3.md

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+# IRCv3 capabilities
+
+echoIRCd implements a broad set of IRCv3 capabilities. Clients negotiate them with `CAP LS` and
+`CAP REQ`.
+
+## Advertised capabilities
+
+```text
+server-time        message-tags          account-tag          account-notify
+extended-join      chghost               multi-prefix         away-notify
+invite-notify      setname               echo-message         userhost-in-names
+batch              labeled-response      standard-replies     extended-monitor
+draft/chathistory  draft/event-playback  draft/message-redaction
+draft/multiline    draft/metadata-2      draft/read-marker    draft/webpush
+draft/account-registration               sts
+```
+
+## Notable features
+
+- **CHATHISTORY** — replay recent conversation, with server-side storage.
+- **labeled-response** + **batch** — correlate replies to the command that caused them.
+- **multiline** — send a message that spans lines as a single logical message.
+- **STS** — advertise a strict-transport-security policy so clients upgrade to TLS.
+- **draft/webpush** — RFC 8291 / 8292 Web Push notifications for supporting clients.
+
+## SASL
+
+SASL is a capability too — see [Accounts & SASL](/docs/accounts) for the supported mechanisms.