JSON to Zig Struct Generator

Optional fields (?T)Inline types

JSON Input

Zig Output (.zig)

What is JSON to Zig Struct Generator?

This tool converts JSON data into Zig struct definitions with std.json and serde.zig support. It generates ready-to-use Zig code with automatic type inference, optional types (?T) for nullable fields, nested struct generation, and inline type definitions.

How to Use

Paste your JSON object or array into the input area
Configure options: root struct name, output mode (std.json or serde.zig), optional fields, inline types
Click "Generate Zig Structs" to create the code
Copy the output and add it to your Zig project

Why Use This Tool?

Automatic type inference from JSON values

Nested struct generation with correct ordering (children first)

Optional types (?T) for nullable fields

Slice types ([]const T) for arrays

serde.zig mode with rename_all blocks for JSON key mapping

Inline struct types for flat, self-contained definitions

Tips & Best Practices

Use realistic sample data for accurate type inference
Enable serde.zig mode for seamless JSON serialization/deserialization
Optional fields (?T) wrap nullable values for safer Zig code
Inline types embed nested structs directly instead of separate declarations

Frequently Asked Questions

What is serde.zig?

serde.zig is a serialization/deserialization library for Zig, inspired by Rust's serde. It provides derive-style attributes like rename_all for mapping JSON keys to Zig field names, making it easy to work with JSON APIs that use camelCase or snake_case conventions.

How are JSON types mapped to Zig?

JSON strings → []const u8, integers → i64, floats → f64, booleans → bool, null → ?T (optional), arrays → []const T, and nested objects → separate Zig structs. When inline types is enabled, nested objects become anonymous struct types inline.

What does the ?T optional type mean in Zig?

In Zig, ?T is an optional type that can hold either a value of type T or null. When "Optional fields" is enabled, JSON null values are mapped to ?T types, making your Zig structs safer by explicitly representing the possibility of missing data.

What is the rename_all serde block?

In serde.zig mode, pub const serde = .{ .rename_all = .camel_case } tells the serialization library to automatically convert Zig field names (camelCase) to match JSON keys. This allows idiomatic Zig naming while working with any JSON naming convention.

Is my data sent to a server?

No, all processing happens entirely in your browser. Your JSON data never leaves your device.