JSON to Go Struct

Generate Go structs with multiple struct tags from any JSON object.

Root struct:

Struct Tags

Input JSON

Go Struct

What is a Go Struct with JSON Tags?

In Go, JSON deserialization uses struct tags to map JSON keys to Go fields. A struct tag like `json:"first_name"` tells encoding/json to map the JSON key first_name to the Go field FirstName. Without the tag, Go requires the field name to exactly match the JSON key (case-insensitive).

Writing Go struct definitions by hand for complex JSON responses is tedious. This tool generates the complete struct hierarchy from any JSON — including nested structs, slice types, and proper json: tags for every field. Paste any JSON object or API response and get ready-to-use Go types in seconds.

JSON to Go Struct Example

Input JSON:

json

{
  "id": 1,
  "name": "Ravi Kumar",
  "active": true,
  "address": { "city": "Surat", "country": "IN" }
}

Generated Go struct:

type RootAddress struct {
	City    string `json:"city"`
	Country string `json:"country"`
}

type Root struct {
	Id      int64       `json:"id"`
	Name    string      `json:"name"`
	Active  bool        `json:"active"`
	Address RootAddress `json:"address"`
}

JSON to Go Type Mapping

JSON type	Go type	Notes
string	string	Mapped directly
integer number	int64	Whole numbers use int64 for safety
float number	float64	Decimal numbers use float64
boolean	bool	true/false → bool
null	interface{}	Nullable fields use the empty interface
object	Struct (named)	Nested objects become separate named structs
array of objects	[]StructName	Typed slice based on first element
array of strings	[]string	Primitive arrays use typed slices

Common Use Cases

▸REST API integration — Paste an API response JSON and instantly get the Go struct needed to decode it with encoding/json.
▸Database model generation — Convert a database record JSON to a Go struct for use with sqlx or GORM.
▸Config file parsing — Generate a Config struct from a sample config.json to use with json.Unmarshal.
▸gRPC / protobuf bridging — Create Go types for JSON bridging layers between REST and gRPC services.

Using the generated struct:

import "encoding/json"

var result Root
err := json.Unmarshal([]byte(data), &result)
if err != nil {
    log.Fatal(err)
}
fmt.Println(result.Name)

Frequently Asked Questions

int64 is the safest default for integers in Go — it avoids overflow on 32-bit systems and matches the range of JSON numbers. You can change it to int or int32 in your code as needed.

JSON null is mapped to interface{} since Go has no direct null type for structs. If you expect nullability, replace interface{} with a pointer type like *string or *int64.

Yes. Field names are converted to PascalCase (CamelCase) as required by Go's exported field convention. The original JSON key is preserved in the json struct tag.

Yes. The generated structs use encoding/json compatible json tags and work directly with json.Marshal and json.Unmarshal from the Go standard library.

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