JSON → UML
DiagramsRender any JSON object as a UML class diagram. Properties and inferred types map to class fields automatically — export as SVG, PNG, or PlantUML markup.
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UML Class Diagram
About JSON → UML
JSON to UML automatically reads your JSON object and produces a UML class diagram. Object keys become class attributes, inferred types appear in the second compartment, and nested objects are rendered as associated classes with directional arrows showing composition. Paste any API response payload and the diagram renders instantly, giving you a shareable visual representation ready for architecture reviews, onboarding docs, or code-generation workflows.
Features
- ✓Accepts raw JSON objects and infers primitive types from sample values
- ✓Nested objects rendered as separate UML classes with composition arrows
- ✓Array properties shown with multiplicity notation (e.g. `items: string[1..*]`)
- ✓Optional properties distinguished with dashed borders
- ✓Export diagram as SVG, PNG, or copy equivalent PlantUML source markup
- ✓Side-by-side raw-input and rendered-diagram panes
- ✓Zoom, pan, and fit-to-screen controls on the diagram canvas
Common Use Cases
- Generating architectural diagrams from existing API response payloads
- Documenting data models discovered during reverse-engineering projects
- Creating UML artifacts for design documents without a dedicated UML tool
- Onboarding new team members to a complex domain model quickly
Frequently Asked Questions
QHow are types inferred from JSON values?
The tool inspects each value: strings become `string`, numbers become `number` (or `integer` if whole), booleans become `boolean`, `null` becomes `null`, objects become sub-classes, and arrays show the element type with `[]` multiplicity.
QCan I add method signatures to the UML classes?
Currently the tool focuses on the data model layer. Method signatures are not inferred from JSON, but you can switch to the PlantUML Generator tool and manually append method compartments to the exported markup.
QHow do I handle very large schemas with many classes?
The canvas supports pan and zoom. You can also collapse individual classes to their title bar by double-clicking them, reducing visual noise while preserving the overall structure.