PlantUML online Viewer and Editor

Authors
  • PlantUML online Viewer and Editor
Series: UML and Software Architecture
Episodes: (5/9)

MassiveDiag PlantUML Online Viewer and Editor

Professional UML Diagramming Made Simple

MassiveDiag's PlantUML online editor provides a powerful, real-time environment for creating, editing, and visualizing UML diagrams through text-based definitions. As a complete PlantUML online editor solution, it transforms simple text code into professional diagrams instantly.

Whether you need PlantUML code to SVG for web integration, PNG for presentations, PDF for documentation, or Word document for business reports, MassiveDiag's PlantUML web server capabilities deliver exceptional results with minimal effort.

my Image

Try MassiveDiag's PlantUML Editor Now →

What is PlantUML?

PlantUML is a powerful open-source tool that allows you to create UML diagrams from a simple text-based description language. Using our PlantUML live editor, you can:

  • Write text descriptions of your diagrams
  • See them rendered in real-time
  • Refine and iterate quickly
  • Export in multiple formats

MassiveDiag brings the power of PlantUML to the web with our comprehensive PlantUML online server implementation.

🧩 Supported UML Diagrams

With our PlantUML online editor, you can create a wide range of professional UML diagrams, including:

  • Sequence diagrams - Visualize interactions between objects
  • Use case diagrams - Document system requirements
  • Class diagrams - Model object-oriented structures
  • Activity diagrams - Represent workflows and processes
  • Component diagrams - Show system structure and dependencies
  • State diagrams - Illustrate state transitions
  • Object diagrams - Depict instances of classes
  • Deployment diagrams - Model physical deployment
  • Timing diagrams - Show timing constraints

📈 Supported Non-UML Diagrams

Beyond traditional UML, MassiveDiag Playground also supports:

  • JSON/YAML data visualization
  • EBNF diagrams for grammar definitions
  • Regex diagrams for pattern visualization
  • Network diagrams (using nwdiag)
  • UI mockups (Salt)
  • Archimate diagrams for enterprise architecture
  • Ditaa diagrams for ASCII art conversion
  • Gantt charts for project planning
  • MindMap diagrams for brainstorming
  • WBS diagrams for project breakdown
  • Entity Relationship diagrams for database design

Getting Started with PlantUML

Sequence Diagram Example

@startuml
actor User
participant "Web App" as Web
participant "API Server" as API
database "Database" as DB

User -> Web: Login
Web -> API: Auth Request
API -> DB: Validate Credentials
DB --> API: User Data
API --> Web: Auth Token
Web --> User: Login Success
@enduml

my Image

Class Diagram Example (Diagrama de Clases)

@startuml
class Customer {
  +String name
  +String email
  +register()
  +login()
}

class Order {
  +int orderId
  +Date createdAt
  +float total
  +process()
}

class Product {
  +String name
  +String description
  +float price
  +isAvailable()
}

Customer "1" -- "many" Order: places
Order "many" -- "many" Product: contains
@enduml

my Image

Activity Diagram Example (Diagrama de Flujo)

@startuml
start
:Check Request;
if (Is Authenticated?) then (yes)
  :Process Request;
  if (Data Valid?) then (yes)
    :Save to Database;
    :Return Success;
  else (no)
    :Return Validation Error;
  endif
else (no)
  :Return Authentication Error;
endif
stop
@enduml

my Image

How to Use MassiveDiag's PlantUML Viewer

  1. Write or Generate Your PlantUML Code
    Use your own code or generate it with your favorite AI tool.
@startuml
start
:User Login;
if (Valid Credentials?) then (Yes)
  :Redirect to Dashboard;
else (No)
  :Show Error Message;
endif
stop
@enduml
  1. Open the Online PlantUML Editor
    Go to the MassiveDiag Playground — no installation needed.

my Image

  1. Select PlantUML as Diagram Type
    Editor auto-detects diagram type or lets you choose manually.

my Image

  1. Create Your Diagram
    Click "Create Diagram" to visualize your code.

my Image

  1. Edit in Real-Time
    Use the dual-pane interface for:

    • Instant preview updates
    • Live code and SVG sync

  2. Export in Your Preferred Format

  • PlantUML code to SVG – For scalable graphics
  • PlantUML code to PNG – For slides and documents
  • PlantUML code to PDF – For official documentation
  • PlantUML code to Word – For business reports

my Image

Create Your First PlantUML Diagram Now →

Advanced PlantUML Examples

Component Diagram

@startuml
package "Frontend" {
  [Web Application] as Web
  [Mobile App] as Mobile
}

package "Backend" {
  [API Gateway] as Gateway
  [User Service] as UserSvc
  [Product Service] as ProdSvc
  [Order Service] as OrderSvc
  database "User DB" as UserDB
  database "Product DB" as ProdDB
  database "Order DB" as OrderDB
}

Web --> Gateway
Mobile --> Gateway
Gateway --> UserSvc
Gateway --> ProdSvc
Gateway --> OrderSvc
UserSvc --> UserDB
ProdSvc --> ProdDB
OrderSvc --> OrderDB
OrderSvc ..> UserSvc: verify user
OrderSvc ..> ProdSvc: check inventory
@enduml

my Image

Entity Relationship Diagram (ERD)

@startuml
entity "Customer" as customer {
  *customer_id : number <<PK>>
  --
  *name : text
  *email : text
  address : text
  registration_date : date
}

entity "Order" as order {
  *order_id : number <<PK>>
  --
  *customer_id : number <<FK>>
  *order_date : date
  *total_amount : number
  shipping_address : text
  status : text
}

entity "Product" as product {
  *product_id : number <<PK>>
  --
  *name : text
  description : text
  *price : number
  category : text
  stock_quantity : number
}

entity "OrderItem" as orderItem {
  *order_id : number <<PK, FK>>
  *product_id : number <<PK, FK>>
  --
  *quantity : number
  *unit_price : number
}

customer ||--o{ order
order ||--o{ orderItem
product ||--o{ orderItem
@enduml

my Image

State Diagram

@startuml
[*] --> Pending: Order Created

state Pending {
  [*] --> PaymentVerification
  PaymentVerification --> InventoryCheck: Payment Received
  InventoryCheck --> [*]: Items Available
}

Pending --> Confirmed: Order Verified
Confirmed --> Processing: Start Fulfillment
Processing --> Shipped: Products Shipped
Shipped --> Delivered: Delivery Confirmed
Delivered --> [*]

Pending --> Cancelled: Cancellation Request
Confirmed --> Cancelled: Cancellation Request
Processing --> Cancelled: Exception Occurs
@enduml

my Image

Practical Use Cases for PlantUML

Software Architecture Documentation

  • System overviews
  • API interaction sequence diagrams
  • Class-based data models
  • Deployment strategies

Database Schema Design

  • Visualize database schema
  • Table relationships
  • Index and constraint planning
  • Shareable ERD diagrams

Business Process Modeling

  • Flowchart diagrams (Diagrama de flujo)
  • System process planning
  • Decision tree visualization
  • Approval workflows

Project Planning

  • Gantt chart timelines
  • Resource allocation
  • Milestone tracking
  • Dependencies and risks

🌐 Multilingual Support

MassiveDiag supports over 20+ languages including:

  • Hindi
  • Arabic
  • Italian
  • Korean
  • German
  • French
  • Spanish
  • Indonesian
  • Japanese
  • Russian
  • Chinese
  • Portuguese
  • Tagalog
  • Tiếng Việt and more

Create "diagrama de flujo" and "diagrama de clases" with ease. Full support for PlantUML 在线 编辑器 and localized UI.

Tips for Effective PlantUML Diagrams

  • Keep it Simple – Focus on clarity
  • Consistent Styling – Improves comprehension
  • Use Color and Notes – Highlight key aspects
  • Organize with Packages – For modularity
  • Include a Legend – For complex diagrams

FAQs About PlantUML and MassiveDiag

Is PlantUML difficult to learn?

No. The syntax is intuitive and beginner-friendly.

Do I need to install anything?

No. MassiveDiag works entirely in your browser.

Can I collaborate with others?

Yes. Share code or export diagrams for easy teamwork.

How to include diagrams in docs?

  • Export as SVG/PNG and embed
  • Use PDF/Word for business reports

Conclusion

MassiveDiag's PlantUML online viewer and editor brings the power of text-based diagramming to your browser, no installs required.

Whether you're creating sequence diagrams, class models, or complex workflows, our live code editor has you covered.

Export in SVG, PNG, PDF, or Word with ease.

Start Creating Diagrams with MassiveDiag →

SHARE