JSON to Python Dataclass
Convert JSON to Python dataclasses online. Infers str, int, float, bool, List and Optional types, builds nested classes and snake_case fields in your browser.
What is the JSON to Python Dataclass?
The ByteTools JSON to Python generator turns a JSON sample into ready-to-use @dataclass definitions.
- Standard-library @dataclass output, no extra packages
- Infers str, int, float, bool, List and Optional types
- Separate class for every nested object, defined before use
- snake_case field names with the original JSON key in a comment
- Defaulted fields ordered last so the code compiles
- 100% private — JSON never leaves your browser
How to use the JSON to Python Dataclass
- 1
Paste a representative JSON sample, or drop a .json file to load it.
- 2
Set the root class name and choose whether field names become snake_case.
- 3
Click Generate dataclasses to infer the class definitions.
- 4
Copy the code or download it as a .py file.
About the JSON to Python Dataclass
The ByteTools JSON to Python generator turns a JSON sample into ready-to-use @dataclass definitions. It infers each field's type, builds a separate class for every nested object, wraps values that can be missing or null in Optional, and orders fields so defaults come last exactly as dataclasses require.
It is built for Python developers modelling API responses, config files and database rows. Instead of hand-writing classes and type hints from a payload, paste the JSON, set a root class name and copy code you can drop straight into a module.
Type inference runs 100% locally in your browser with JavaScript — no Python and no server involved. Your JSON is never uploaded or stored, so it is safe for internal APIs and confidential data models.
Frequently asked questions
How do I convert JSON to a Python dataclass?
Paste your JSON sample, set a root class name and click Generate dataclasses. Every object becomes a class with typed fields, nested objects get their own classes, and the result is plain standard-library Python you can paste into a file.
Which Python version does the generated code need?
Dataclasses require Python 3.7 or newer. The output starts with 'from __future__ import annotations' and uses typing.List and typing.Optional, so it works on every supported version without extra dependencies.
What happens to keys that are not valid Python identifiers?
They are converted into a valid snake_case name, and a trailing comment records the original JSON key so you can add a serialisation alias if you need one. Python keywords get a trailing underscore.
How are optional and null fields typed?
A key that is missing from some objects, or that is null anywhere in the sample, is typed as Optional and given a default of None. Those fields are emitted after the required ones, which dataclasses insist on.
Is my JSON uploaded anywhere?
No. The conversion runs entirely in your browser with JavaScript. Nothing is sent to a server or stored, so confidential API responses stay private.
Related tools
JSON to TypeScript
Generate TypeScript interfaces from a JSON sample online. Infers types recursively, merges array shapes and marks optional keys — 100% in your browser.
JSON to Java POJO
Convert JSON to a Java POJO online with private fields, getters and setters, Jackson @JsonProperty and nested classes — free and 100% in your browser.
JSON to Go Struct
Convert JSON to Go structs online with exported fields and json tags. Generates nested structs and slice types from a sample — free and 100% in-browser.
JSON Schema Generator
Generate a JSON Schema (draft-07 or 2020-12) from a sample JSON document. Infers types, required keys and array items for validation — 100% in your browser.
JSON Formatter
Format, beautify and minify JSON online with 2-space, 4-space or tab indentation. Sort keys alphabetically and catch syntax errors instantly — free and private.