Participants and groups

Participants and icons

Participants are shared definitions. Name, type, description, technology, and explicit icon changes appear everywhere that participant is used. Each sequence has its own participant membership, column order, widths, colors, and lifelines.

Every type has a generic icon, even when pasted AAL omits an icon. Select a participant → Change icon to search the same icon libraries as System Design. Use automatic icon removes the explicit choice. A missing image falls back visually without modifying its saved icon path.

participant Auth "Authentication API" {
    type api
    technology "HTTPS"
    icon "/deployment-icons/generic/integration.svg"
}

Drag a header horizontally to change its local column order. Select it to expose left/right resize handles; focus a handle and use the arrow keys for precise width changes. Icons stay on the left and names wrap on the right.

Participant groups

Use Add group to place related participants inside a named band, like an application or external platform. Select the band heading to rename it, set a custom type, choose an icon, edit membership, style its background, border and text, or ungroup. Participants and messages survive ungrouping.

group Platform "Digital Application" {
    participants [Portal, Auth]
    type "Application"
    icon "/deployment-icons/generic/application.svg"
}

Each participant belongs to at most one group; groups cannot nest and must contain a participant. Membership is shared across all sequences. Groups show their visible members in contiguous columns and extend behind their lifelines. Colors stay in project appearance settings; groups do not replace fragments or sequence membership. The icon, name, and type align at the top left. Omitted types display as Group and omitted icons use a generic component icon. The box and header space adjust to fit the visible participants and wrapped text.