UML Diagram Generator
Quick Start: Choose diagram type → Write PlantUML text → Define elements and relationships → Wrap in ``` `plantuml ``` fence.
⚠️ IMPORTANT: Always use ````plantuml``or```puml``code fence. NEVER use```text``` — it will NOT render as a diagram.
Critical Rules
- Every diagram starts with
@startumland ends with@enduml - Use standard PlantUML keywords:
class,interface,abstract,enum,actor,participant,component,node,database,package - Relationships use arrow syntax:
-->,<|--,*--,o--,..>,..|> - Use
skinparamfor global styling and colors - Use
#coloron individual elements for specific colors - Notes use
note left of,note right of,note over, or standalonenote "text" as N
UML Diagram Types
| Type | Purpose | Key Syntax | Example | ||
|---|---|---|---|---|---|
| Class | Class structure and relationships | class, interface, `<\ | --` | class-diagram.md | |
| Sequence | Message interactions over time | participant, ->, --> | sequence-diagram.md | ||
| Activity | Workflow and process flow | start, :action;, if/else | activity-diagram.md | ||
| Swimlane Activity | Multi-role activity with swimlanes | `\ | Lane\ | , :action;` | swimlane-activity-diagram.md |
| State Machine | Object lifecycle states | state, [*] --> | state-machine-diagram.md | ||
| Component | System component organization | component, [name], interface | component-diagram.md | ||
| Use Case | User-system interactions | actor, usecase, (name) | use-case-diagram.md | ||
| Deployment | Physical deployment architecture | node, artifact, database | deployment-diagram.md | ||
| Object | Runtime object snapshot | object "name" as id | object-diagram.md | ||
| Package | Module organization | package "name" | package-diagram.md | ||
| Communication | Object collaboration | Numbered messages with sequence syntax | communication-diagram.md | ||
| Composite Structure | Internal class structure | component with nested port | composite-structure-diagram.md | ||
| Interaction Overview | Activity + sequence combination | group, ref over | interaction-overview-diagram.md | ||
| Profile | UML extension mechanisms | <<stereotype>> labels | profile-diagram.md |
Mxgraph Stencil Icons
draw-uml supports 9500+ mxgraph stencil icons (AWS, Azure, Cisco, Kubernetes, etc.) via the mxgraph.* syntax. Default colors are applied automatically — you do NOT need to specify fillColor or strokeColor.
Full stencil reference: See stencils/README.md.
Syntax
mxgraph.<namespace>.<icon> "Label" as <alias>
mxgraph.<namespace>.<icon> "Label" as <alias> #color
mxgraph.<namespace>.<icon> <alias>mxgraph.<namespace>.<icon>— the stencil shape key (e.g.mxgraph.aws4.lambda,mxgraph.kubernetes.pod)"Label"— display text (quoted if contains spaces, unquoted for single word)as <alias>— identifier for use in relationships#color— optional override color (e.g.#FF6600,#LightBlue)
Examples
@startuml
' Simple icon declaration
mxgraph.aws4.lambda "Lambda\nFunction" as fn
mxgraph.aws4.api_gateway "API GW" as gw
mxgraph.aws4.dynamodb "DynamoDB" as db
gw --> fn
fn --> db
@enduml@startuml
' Kubernetes architecture with icons
mxgraph.kubernetes.ing "Ingress" as ing
mxgraph.kubernetes.svc "Service" as svc
mxgraph.kubernetes.pod "Pod" as pod
mxgraph.kubernetes.deploy "Deployment" as deploy
ing --> svc
svc --> pod
deploy --> pod
@enduml@startuml
' Mixing standard UML with stencil icons
node "Cloud" {
mxgraph.aws4.ec2 "EC2" as ec2
mxgraph.aws4.rds "RDS" as rds
}
database "Legacy DB" as legacy
ec2 --> rds
rds --> legacy
@enduml