How This JSON to Go Struct Converter Works
Paste a JSON object (or a JSON array, the first element's shape is used) and this json to go struct tool, functioning as a general-purpose json to golang converter, walks every field, infers its Go type, and emits a struct definition with a json tag on each field matching the original JSON key, effectively letting you generate go struct from json in one pass to convert json to golang without hand-typing field names and types. Four options shape the output: the root struct name, whether nested objects become json to go pointer fields (a golang struct from json with pointers instead of values), whether fields get an omitempty tag, and whether nested objects are emitted as inline anonymous structs or as separate named types declared alongside the root struct. The result is copy-ready Go, package main followed by every generated struct, root first.
Go Type Inference: How JSON Types Map to Go
Type inference follows a straightforward mapping, but one part of it is worth understanding precisely: any JSON number without a decimal point becomes int64, any number with one becomes float64, based purely on how that specific value is written in the sample you pasted. This is sample-based inference, not a real schema, if a field holds 5 in your sample but could realistically be 5.5 in another response, this tool has no way to know that from one JSON document alone, review the inferred numeric types against your actual API behavior rather than trusting them blindly for fields that might vary.
| JSON type | Inferred Go type | Notes |
|---|---|---|
| string | string | |
| boolean | bool | |
| number (no decimal) | int64 | Based on this sample only |
| number (has decimal) | float64 | |
| null | *interface{} | Pointer, since the concrete type is unknown |
| array | []T | T inferred from the first element |
| object | struct (named or inline) | Depends on the inline structs option |
Pointers, omitempty, and Inline Structs Explained
Go struct json tags generator options each solve a specific, common Go/JSON friction point. Pointer fields (for nested objects) let you distinguish a field that was entirely absent from the JSON from one that was present but held Go's zero value, without pointers, both cases collapse to the same zero-valued struct after unmarshaling. The go omitempty json tag skips a field entirely when marshaling back to JSON if it holds its zero value, useful for keeping generated request bodies clean instead of sending explicit zeros and empty strings for everything. Inline structs trade reusability for a flatter, single-block definition, useful for a quick one-off struct, separate named types (the default) are usually better once a nested shape gets reused or grows past a field or two.
Common Uses
Generating a starter struct from a real API response before writing a Go HTTP client, converting a webhook payload sample straight into a typed struct instead of hand-writing field names and types, quickly checking what struct shape a deeply nested json to go struct conversion would actually produce, and standardizing on consistent omitempty usage across a codebase are the most common uses of this json to go online tool. Comparing pointer-field output against value-field output side by side, to decide which fits a given API's semantics, is a common secondary use.
What This Tool Doesn't Do
Type inference is based entirely on the one JSON sample you paste in, not a real schema, a field that's sometimes a string and sometimes null across different API responses won't be caught from a single example. For array fields, only the first element's shape is used to infer the element type, if array elements vary in shape, that variation is invisible to this tool. It doesn't generate validation logic, custom UnmarshalJSON/MarshalJSON methods, or any struct methods beyond the bare field definitions, and it doesn't handle every numeric edge case precisely, very large integers or values meant to use encoding/json's json.Number for precision aren't specially handled, they follow the same int64/float64 inference as everything else.