UML Diagram Online

• Plan System Requirements

Clarify what users, roles, and external systems need to do before development starts. Draw use case diagrams to define system boundaries, actors, and expected functionality, then connect supporting notes or requirements to the relevant parts of the diagram.

• Design Software Structure

Map how the system is organized before writing or updating code. Design class diagrams, object diagrams, package diagrams, and composite structure diagrams to model classes, attributes, methods, interfaces, objects, namespaces, and relationships.

• Model System Behavior

Show how a system, feature, or process behaves under different conditions. Build activity diagrams, state machine diagrams, interaction overview diagrams, and timing diagrams to map workflows, decisions, state changes, event timing, and process logic.

• Map Interactions Between Components

Explain how users, objects, services, or system components communicate over time. Create sequence diagrams and communication diagrams to show message order, service calls, API interactions, user flows, and object relationships.

• Document System Architecture

Show how software components, modules, services, and deployment environments fit together. Make component diagrams, deployment diagrams, and package diagrams to document dependencies, infrastructure, execution environments, and high-level architecture.

• Review and Share Technical Designs

Draw UML diagrams to align developers, architects, product managers, analysts, and stakeholders before implementation. Create different UML views in the same workspace, add comments for review, and export or share diagrams for technical documentation, planning, and handoff.