JSON Builder

Build JSON visually.

Output / Result

About the JSON Builder

The JSON Builder lets you construct valid JSON documents visually — no typing curly braces or worrying about commas. Add keys, choose value types, and nest objects or arrays with a click. The output panel updates in real time.

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How to use it
  1. Click + to add a new field to the current object or array.
  2. Type a key name in the left input (skipped for array items).
  3. Choose a type — string, number, boolean, null, object, or array.
  4. For primitive types, enter the value in the right input.
  5. For object or array types, a nested group appears — add child fields inside it.
  6. Click − to remove any field.
  7. Use Copy in the output panel to grab the generated JSON.
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Tips & use cases
  • Prototype an API request body before writing any code.
  • Create sample config files (e.g. package.json, CI config) without memorising syntax.
  • Teach JSON structure — the visual nesting makes objects and arrays easy to explain.
  • Mix types freely: a field can be a string at the top level and an array two levels down.
  • The output is always valid JSON — the builder enforces correct formatting automatically.
StringAny text value, e.g. "hello"
NumberInteger or decimal, e.g. 42
Booleantrue or false
NullExplicit empty / missing value
ObjectKey-value pairs inside { }
ArrayOrdered list of values inside [ ]