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JSON to Dart Class

Convert representative JSON into reviewable Dart output with type inference, nested models, arrays, and practical generation settings.

Infer types from representative JSON Generate nested models or structures Keep source and result separate Produce copy-ready output for review
Types are inferred from the sample values. Review arrays, nullability, dates, numeric ranges, and domain constraints before production use.
INPUT Sample JSON *
0 chars0 words0 lines

Tool settings

Ctrl / ⌘ + Enter
Generated code
About the tool

What JSON to Dart Class does

JSON to Dart Class converts representative JSON into a clean Dart model scaffold. It infers basic strings, integers, floating-point values, booleans, arrays, and nested objects, then produces readable code with a root type name you control.

JSON to Dart Class is useful for API integration, SDK work, prototypes, fixtures, webhook payloads, and documentation when a real JSON response already shows the shape of the data. The output saves repetitive typing while keeping the generated model easy to review.

Because one sample cannot describe every optional field, enum, date, union, numeric range, or domain constraint, JSON to Dart Class should be treated as a strong starting point rather than an automatic replacement for the real API contract.

JSON to Dart Class visual guide showing JSON input, type inference, and generated Dart output
A practical review workflow for JSON to Dart Class.

How to use

  1. 1. Paste a representative JSON object or an array containing a representative object.
  2. 2. Choose the root model, class, or struct name and review the available settings.
  3. 3. Run JSON to Dart Class once to generate the initial Dart output.
  4. 4. Inspect nested types, arrays, names, nullability, and any inferred storage or serialization choices.
  5. 5. Test the result in the real project before production use.
Built for the task

Why use JSON to Dart Class?

Focused controls, predictable output, and a workflow designed around this exact transformation.

01

Fast Dart model scaffolding

Turn a representative JSON object into readable Dart code without recreating every field manually.

02

Nested type generation

Nested JSON objects become separate named model types referenced by the parent.

03

Collection-aware output

Arrays map to practical collection types for the target language.

04

Reviewable serialization mapping

JSON property names are preserved through language-appropriate tags, keys, attributes, or field naming where needed.

Useful answers

Questions about JSON to Dart Class

Practical details about input, output, privacy, limits, and the best way to use this tool.

01 Does JSON to Dart Class support nested JSON?

Yes. Nested objects are converted into additional Dart model types and referenced from the parent.

02 Can JSON to Dart Class detect optional fields?

One sample cannot prove that every field is always present. Enable optional or nullable output when the source may omit properties, then review the result against the real contract.

03 Does JSON to Dart Class detect dates, UUIDs, and enums?

Not reliably from a single sample value. Strings stay strings unless you intentionally adapt the generated code to a date, UUID, URL, enum, or domain-specific type.

04 Can JSON to Dart Class handle arrays?

Yes. Arrays are mapped to a native or idiomatic collection representation. Heterogeneous arrays still require manual review.

05 Is the generated Dart code production ready?

It is a scaffold. Compile or lint it in the real project and review naming, imports, nullability, collections, serialization, validation rules, and framework conventions.

Learn JSON

Read the complete JSON Guide

Learn JSON objects, arrays, value types, validation, formatting, parsing, API workflows, and common syntax errors.

  • Objects, arrays, and values
  • Validation and formatting
  • API and parsing workflows
Read guide Practical explanations and examples

How JSON to Dart Class works

JSON to Dart Class reads the structure of the sample JSON and maps each observed value to a practical Dart type. Strings remain strings, booleans map to boolean types, integer and decimal values map to numeric types, arrays become collections, and nested objects become named child models. The source JSON remains the evidence for the generated scaffold.

Use realistic input with JSON to Dart Class

Representative input produces more useful code than a minimal two-field example. Include nested objects, arrays, booleans, decimals, and fields that reflect the payload your application actually receives. If some properties can be absent or null, enable the optional setting and still compare the output with the official API contract.

Review type inference from JSON to Dart Class

JSON to Dart Class can recognize the shape of observed values, but it cannot infer business meaning. The integer 42 may be an ID, counter, enum value, or quantity. A string may actually represent a date, UUID, URL, email address, or constrained code. Replace basic types with richer Dart types when your application semantics require them.

Arrays, nested objects, and nullability

Arrays deserve special attention because one representative item does not prove that every element has the same shape. Heterogeneous collections may require a union, interface, sealed type, generic value, or custom decoder. Missing properties and explicit null values also behave differently across languages and serializers, so review optionality deliberately.

Validate the generated Dart model

After using JSON to Dart Class, compile or lint the output in the destination project. Check imports, package or namespace placement, type names, nested models, collection item types, serialization metadata, nullable fields, and validation annotations. Add constraints from the real specification rather than guessing from the sample.

Continue with related Trexmi tools

Prepare the source with JSON Formatter and continue the workflow with JSON Schema Generator. These internal tools help you inspect the same JSON before or after generation.

External reference for JSON to Dart Class

For language and platform details, review the Dart language documentation. The official documentation remains authoritative for syntax, serialization behavior, version differences, and production conventions.

Privacy and final checks

Avoid pasting access tokens, passwords, private keys, customer records, or confidential production payloads into any environment you do not trust. JSON to Dart Class only needs representative structure, so synthetic sample data is usually enough. Keep an untouched copy of important source data and verify the generated output in the destination project.