JSON to Go Struct Converter - Generate Golang Structs

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How to JSON to Go Struct Online

1. 1

   Paste JSON Payload or JSON Schema: Paste your sample JSON object, REST API response, webhook payload, array slice, or JSON Schema Draft-07 specification into the input editor.

2. 2

   Set Root Struct Identifier: Enter a PascalCase identifier for your top-level Go struct (e.g., "UserProfile", "OrderPayload", "MetricsApiResponse").

3. 3

   Configure Omitempty Struct Tags: Toggle the omitempty modifier to include `,omitempty` on generated `json:"..."` struct tags for compact JSON output.

4. 4

   Enable Pointer Types for Optionals: Choose whether nullable and optional fields should be typed as Go pointers (`*string`, `*int64`, `*bool`) to distinguish between missing and zero values.

5. 5

   Generate Golang Structs: Click "Convert" or press ⌘↵ (Ctrl+Enter on Windows/Linux) to instantly compute the Go struct hierarchy and type mappings.

6. 6

   Copy & Integrate: Copy the generated Go code with ⌘⇧C or download the .go file to use with standard `encoding/json` in your Go backend services or CLI applications.

JSON to Go Struct Features

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  Standard encoding/json Tags: Emits idiomatic `json:"..."` struct tags adhering strictly to Go standard library serialization standards.

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  Recursive Struct Decomposition: Recursively parses nested JSON objects and arrays into distinct, modular PascalCase child structs with parent references.

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  Sound Nullability with Pointers: Automatically maps nullable and optional JSON fields to Go pointer types (`*string`, `*float64`, `*bool`), eliminating ambiguity between null and zero values.

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  Configurable omitempty Tagging: Easily toggle `,omitempty` on all struct tags to strip zero-value fields during JSON marshaling.

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  Automatic ISO-8601 Date Detection: Identifies standard ISO-8601 and RFC 3339 datetime strings, emitting typed `time.Time` fields and automatic `"time"` package imports.

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  Idiomatic Go Initialism Capitalization: Enforces Golint/Uber Go naming rules by keeping standard acronyms uppercase (e.g., `UserID`, `APIURL`, `IPAddress`, `JSONData`, `HTTPStatus`).

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  Typed Slice Inference: Inspects JSON arrays of primitives or objects to generate strongly typed Go slices (`[]string`, `[]LineItem`).

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  JSON Schema Draft Ingestion: Parses JSON Schema Draft-07 and 2020-12 documents, respecting `required` arrays and schema primitive definitions.

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  Structural Hierarchy Metrics: Calculates total generated struct count, distinct field count, and maximum nesting depth for complex data models.

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  Arbitrary Payload Fallbacks: Maps unknown or polymorphic union fields safely to `interface{}` or `any` for dynamic runtime decoding.

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  100% In-Browser Privacy: All parsing, tree traversal, and code synthesis run client-side in your web browser. Zero JSON bytes are transmitted over the network.

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  Keyboard-Driven Workflow: High-speed developer controls with ⌘↵ for generation, ⌘⇧C for copying output, and ⌘⇧K for clearing inputs.

Supported Formats & Dialects

The JSON to Go Struct supports 6 syntax formats and dialects for accurate parsing and processing.

Standard JSON Struct Tags (`json:"field_name"`)

Standard field tags parsed by the `encoding/json` package. Maps JSON keys (snake_case, camelCase, kebab-case) to exported Go struct fields.

Omitempty Serialization Modifier (`json:"key,omitempty"`)

Instructs `json.Marshal()` to omit the struct field from the serialized JSON output if the field holds its type zero value (empty string, 0, false, nil pointer).

Pointer Types for Nullable Fields (`*string`, `*int64`, `*bool`)

Wraps nullable JSON fields in Go pointers to cleanly distinguish between an explicitly provided zero value (e.g., `false` or `0`) and an absent/null value (`nil`).

ISO-8601 Timestamp Parsing (`time.Time`)

Leverages Go standard `time.Time` type with built-in RFC 3339 JSON unmarshaling for ISO-8601 date and time strings.

Multi-Format Struct Tags (`json:"..." yaml:"..." bson:"..."`)

Enables Go structs to be deserialized across multiple format adapters simultaneously, including JSON, YAML, MongoDB BSON, and URL query params.

Deferred & Dynamic Payloads (`json.RawMessage` & `any`)

Utilizes `json.RawMessage` (`[]byte`) to delay parsing for discriminated polymorphic unions, or `any` (`interface{}`) for unstructured dynamic JSON.

Frequently Asked Questions

How does Go encoding/json deserialize JSON into typed structs via reflection?

Go standard library package `encoding/json` uses runtime reflection (`reflect` package) during `json.Unmarshal()`. It inspects the exported fields of the target struct and reads their `json:"..."` struct tags. When parsing JSON key-value pairs, it performs case-insensitive or exact tag matching to find the corresponding struct field, converts primitive JSON types into Go types (numbers, booleans, strings), and allocates child structs and slices as needed.

Why must Go struct fields be capitalized for JSON serialization?

In Go, identifier visibility is determined by the first letter of the identifier. Fields starting with an uppercase letter (`Name`) are public/exported, allowing external packages like `encoding/json` to read and write them via reflection. Fields starting with a lowercase letter (`name`) are unexported and private to the package; `json.Marshal()` and `json.Unmarshal()` silently ignore unexported fields.

What is the difference between value fields and pointer fields (*T) when unmarshaling JSON nulls?

Value fields (e.g., `Score int`, `IsActive bool`) cannot be `nil` in Go; if the JSON payload contains `null` or omits the key, Go assigns the default zero value (`0` or `false`). Pointer fields (e.g., `Score *int`, `IsActive *bool`) can hold `nil`. If the key is omitted or explicitly set to `null`, the pointer remains `nil`. If a value is present (e.g. `0` or `false`), Go allocates memory and stores the pointer, allowing you to unambiguously detect whether the client submitted a zero value or omitted the field.

What are the common gotchas when using omitempty on boolean and numeric fields in Go?

The `omitempty` tag option tells `json.Marshal()` to omit a field if it equals the zero value of its type (`""` for strings, `0` for numbers, `false` for booleans, `nil` for pointers). A common bug occurs with boolean flags like `IsActive bool `json:"is_active,omitempty"`: if `IsActive` is `false`, `json.Marshal()` omits `"is_active": false` from the JSON payload because `false` is the zero value! To allow sending explicit `false` or `0` values while still omitting nulls, define the field as a pointer (`*bool`, `*int`).

How does the converter infer and map JSON numbers (float64 vs int64)?

JSON specification RFC 8259 does not distinguish between integers and floats—all numerical values are arbitrary-precision decimal numbers. By default, the generator maps numbers to `float64` to prevent fractional truncation. In your Go codebase, if a field represents an integer ID or timestamp, you can change `float64` to `int64` or `uint64`. For preserving high-precision 64-bit numbers without floating-point rounding, you can also use `json.Number` with `decoder.UseNumber()`.

How are ISO-8601 date and timestamp strings handled with time.Time in Go?

The generator detects strings matching ISO-8601 and RFC 3339 formats (e.g., `"2026-09-06T12:00:00Z"`) and maps them to `time.Time` (or `*time.Time` for nullable dates), adding `import "time"` automatically. Go `time.Time` natively implements `json.Marshaler` and `json.Unmarshaler`, automatically serializing to and deserializing from RFC 3339 formatted strings.

How does Go naming convention handle acronyms and initialisms (e.g. ID, URL, HTTP, API)?

Official Go naming conventions (enforced by `golint`, `revive`, and the Uber Go Style Guide) require that standard initialisms and acronyms remain in consistent case. For example, use `UserID` (not `UserId`), `APIURL` (not `ApiUrl`), `HTTPStatus` (not `HttpStatus`), and `IPAddress` (not `IpAddress`). This converter automatically applies these initialism rules when generating exported Go field names.

How does the converter decompose deeply nested JSON objects into separate Go structs?

Rather than generating unreadable inline anonymous struct definitions (`struct { Sub struct { ... } }`), the converter recursively analyzes the JSON tree. It extracts each nested object and array item into an independent PascalCase struct named after its path (e.g. `Order`, `OrderCustomer`, `OrderCustomerAddress`). The parent struct references the child struct by type name, producing clean, reusable, and modular Go code.

When should you use json.RawMessage or any (interface{}) instead of concrete struct types?

`any` (or `interface{}`) is used for arbitrary, completely unstructured JSON where fields cannot be predicted at compile time. `json.RawMessage` is a byte slice (`[]byte`) that delays JSON unmarshaling. It is ideal for polymorphic JSON payloads (such as webhook events or JSON-RPC envelopes) where a top-level `type` discriminator dictates which concrete sub-struct should be unmarshaled in a second pass.

How can you parse JSON with custom date formats or non-standard encodings in Go?

If an API returns non-standard date formats (e.g., `"2026/09/06"` or Unix timestamps as strings), you can create a custom type and implement the `json.Unmarshaler` interface (`UnmarshalJSON([]byte) error`). Inside `UnmarshalJSON`, parse the raw byte slice with `time.Parse()` or custom logic and assign the result to your struct field.

Can this tool generate Go structs directly from JSON Schema specifications?

Yes. If you paste a JSON Schema document (Draft-07 or Draft 2020-12 containing `$schema` and `properties`), the converter detects the schema structure. It reads the `required` list to determine mandatory vs pointer optional fields, maps schema types (`string`, `integer`, `number`, `boolean`, `array`, `object`) to corresponding Go types, and produces complete struct declarations.

Is any JSON data sent to a backend server during Go struct generation?

No. The JSON to Go Struct converter executes 100% in your browser using client-side JavaScript. Your JSON payloads, sensitive API responses, customer records, and internal schema files never leave your device and are never sent to any server.

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