How does the JSON to Go Struct converter handle nested JSON objects?

The converter automatically identifies nested JSON objects and extracts them into separate, cleanly named Go struct types or inline nested struct definitions based on your settings.

Can I automatically add 'omitempty' tags to generated Go structs?

Yes. You can toggle options to include 'omitempty' in the struct tags so that empty or null JSON fields are omitted during JSON marshaling in Go.

How are JSON arrays converted into Go types?

Arrays of primitives are converted to slices like []string or []int. Arrays containing objects are evaluated to infer a common struct slice, such as []MyStruct.

Is my JSON payload sent to any remote server?

No. The entire conversion process runs 100% locally in your browser using JavaScript. Zero data is uploaded or stored on any server.

JSON to Go Struct Converter: Online Go Generator

JSON to Go Struct Converter

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// Go structs appear here

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JSON to Go Data Type Mapping Matrix

JSON Data Representation	Inferred Go Type	Golang Package	Allocation / Usage Note
`42`	`int`	builtin	Platform-sized (32/64-bit); fine for counts
`-7`	`int`	builtin	Signed; negative values are valid
`2147483647`	`int32`	builtin	Fixed 32-bit; overflow errors on Unmarshal
`9007199254740993`	`int64`	builtin	Above 2^53; use for IDs and counters
`1700000000` (Unix seconds)	`int64`	builtin, time	Convert with `time.Unix(v,0)`
`1700000000000` (Unix ms)	`int64`	builtin, time	Convert with `time.UnixMilli(v)`
`255`	`uint8`	builtin	Byte-sized unsigned; rejects negatives
`65535`	`uint16`	builtin	Ports, small enums
`4294967295`	`uint32`	builtin	Unsigned 32-bit
`18446744073709551615`	`uint64`	builtin	Exact in Go, lossy in JavaScript
`3.14`	`float64`	builtin	Default Go type for JSON decimals
`1.5`	`float32`	builtin	Half the memory, lower precision
`1e9`	`float64`	builtin	Exponent notation decodes as float
`0`	`int`	builtin	Zero value; dropped by `omitempty`
`19.99` (money)	`int64` (cents)	builtin	Avoid float for currency; store minor units
`12345678901234567890123`	`*big.Int`	math/big	Arbitrary precision; implements TextUnmarshaler
Number kept as text	`json.Number`	encoding/json	Use with `dec.UseNumber()`
`true`	`bool`	builtin	Zero value is `false`
`false`	`bool`	builtin	Cannot tell false from missing; use `*bool`
`"text"`	`string`	builtin	UTF-8; invalid bytes become U+FFFD
`""`	`string`	builtin	Empty string is the zero value
`"2026-10-26T20:25:00Z"`	`time.Time`	time	RFC3339 parsed automatically
`"2026-10-26T20:25:00+05:30"`	`time.Time`	time	Offset preserved in Location
`"2026-10-26"`	`string`	builtin, time	Date-only fails time.Time; parse with layout `2006-01-02`
`"20:25:00"`	`string`	builtin	Time of day; no stdlib type
`"1h30m"`	`time.Duration`	time	Needs custom UnmarshalJSON
`"550e8400-e29b-41d4-a716-446655440000"`	`uuid.UUID`	github.com/google/uuid	Or plain `string` without dependency
`"dev@example.com"`	`string`	builtin, net/mail	Validate with `mail.ParseAddress`
`"https://example.com"`	`string`	builtin, net/url	Parse later with `url.Parse`
`"192.168.1.1"`	`net.IP`	net	Implements TextUnmarshaler
`"SGVsbG8="`	`[]byte`	builtin	Standard base64 decoded automatically
`"#ff0000"`	`string`	builtin	No native color type
`null`	`interface{}` / `any`	builtin	Type unknown; assert at runtime
`null` in string field	`*string`	builtin	nil means null or absent
`null` in number field	`*int`	builtin	Separates 0 from null
`null` in boolean field	`*bool`	builtin	Tri-state: true, false, nil
`null` in object field	`*Address`	builtin	Pointer to sub-struct
Optional string	`*string` + `omitempty`	builtin	Omitted when nil, kept when empty
Optional int (0 is valid)	`*int` + `omitempty`	builtin	Pointer to 0 is still emitted
Optional decimal	`*float64`	builtin	nil when absent
Optional boolean	`*bool`	builtin	Needed for PATCH payloads
Optional nested object	`*Profile`	builtin	nil avoids empty-object output
Optional timestamp	`*time.Time`	time	Pair with `omitempty` or `omitzero`
`{}`	`struct{}`	builtin	Zero-size; or `map[string]any`
`{"a":1,"b":2}` fixed keys	`struct`	builtin	Fastest; keys known at compile time
`{"a":1,"b":2}` dynamic keys	`map[string]int`	builtin	Key order not preserved
`{"k":"v"}`	`map[string]string`	builtin	Headers, labels, env vars
Mixed-value object	`map[string]interface{}`	builtin	Numbers decode as float64
`{"a":{"x":1}}`	`map[string]map[string]int`	builtin	Nested maps allocate per level
Nested object	Named struct	builtin	Reusable and testable
Single-use nested object	Anonymous `struct{...}`	builtin	Inline; cannot be reused
Deferred or polymorphic object	`json.RawMessage`	encoding/json	Zero-copy until decoded again
`[]`	`[]interface{}`	builtin	Element type unknown
`["a","b"]`	`[]string`	builtin	Grows dynamically
`[1,2,3]`	`[]int`	builtin	Use `[]int64` for large IDs
`[1.5,2]`	`[]float64`	builtin	Mixed int and float widen to float64
`[true,false]`	`[]bool`	builtin	Flags
`[{...},{...}]`	`[]Item`	builtin	Contiguous memory; copies on append
`[{...},{...}]` (large)	`[]*Item`	builtin	Shared or mutated elements
`[[1,2],[3]]`	`[][]int`	builtin	Jagged matrix
`[1,"a",null]`	`[]interface{}`	builtin	Type-switch each element
`[1,"a"]` tuple	`[]json.RawMessage`	encoding/json	Decode each index separately
`[10.5,20.1]` fixed length	`[2]float64`	builtin	Array; extra items are dropped
`["a","b"]` unique set	`map[string]struct{}`	builtin	Needs custom UnmarshalJSON
`"active"` enum	`type Status string`	builtin	Add consts and a validating Unmarshal
`"123"` quoted number	`int64` + `,string`	encoding/json	Common in JS-safe APIs
`"true"` quoted bool	`bool` + `,string`	encoding/json	Tag option handles quoting
Key `"$ref"`	`Ref string`	builtin	Tag `json:"$ref"` maps odd keys
Key `"user-name"`	`UserName string`	builtin	Tag required for dashes
String or number value	Custom type	encoding/json	Implement `UnmarshalJSON`

Golang Struct Tag Configuration Matrix

Struct Tag Format	Behavior During json.Marshal	Behavior During json.Unmarshal	Best-Practice Scenario
`json:"name"`	Writes key `name`	Matches key `name`, case-insensitive	Default API field mapping
`json:"name,omitempty"`	Skips false, 0, nil, "", empty slice or map	No effect	Optional fields in responses
`json:"-"`	Field never written	Field never read	Passwords, tokens, internal state
`json:"-,"`	Writes key literally named `-`	Reads key `-`	Rare; API with a dash key
`json:",omitempty"`	Uses Go field name, skips empty	Matches Go field name	Keep names, drop empties
`json:"id,string"`	Writes number as quoted string	Accepts quoted number only	int64 IDs consumed by JavaScript
`json:"id,omitempty,string"`	Quoted, and skipped when 0	Accepts quoted number	Optional stringified IDs
`json:"at,omitzero"`	Skips zero value, including `time.Time{}` (Go 1.24+)	No effect	Timestamps and structs
`json:"user_id" db:"user_id"`	Same as plain json tag	Same as plain json tag	sqlx row scanning plus JSON
`json:"x" validate:"required"`	No effect	No effect; validate after decoding	Request validation
No tag, exported field	Key equals Go field name	Case-insensitive match	Quick prototypes only
Unexported field	Ignored	Ignored	Private state, cannot be tagged
Embedded struct, no tag	Fields promoted to parent	Fields promoted to parent	Shared base fields
`*T` with `omitempty`	Skips nil only; pointer to 0 is written	Allocates when key present	PATCH and nullable columns

Technical Q&A / FAQ Matrix

Technical Developer Question	Exact Go Idiomatic Solution & Code Snippet
How do I handle dynamic JSON keys?	Decode into a map: `var m map[string]Item; err := json.Unmarshal(b, &m)`. Use `map[string]any` if values vary.
How do I tell 0 apart from a missing field?	Use a pointer: Age int `json:"age,omitempty"`, then `if u.Age == nil { / absent */ }`.
How do I parse a mixed-type array?	Use `[]json.RawMessage` and decode per index, or `[]any` with `switch v := x.(type)`.
How do I write custom unmarshaling?	Implement `func (t *T) UnmarshalJSON(b []byte) error`. Use an alias `type alias T` inside to avoid infinite recursion.
How do I stop large int64 losing precision?	Use `dec := json.NewDecoder(r); dec.UseNumber()` for `any` targets, or declare the field `int64`.
How do I reject unknown fields?	`dec := json.NewDecoder(r); dec.DisallowUnknownFields(); err := dec.Decode(&v)`.
How do I accept a value that is string or number?	Define `type Flex string` and in `UnmarshalJSON` trim quotes when `b[0] == '"'`, else use `string(b)`.
How do I parse a non-RFC3339 date?	Create `type Date struct{ time.Time }` and parse inside `UnmarshalJSON` with `time.Parse("2006-01-02", s)`.
How do I keep unknown fields while using a struct?	Decode twice: once into the struct, once into `map[string]json.RawMessage`, then delete known keys.
How do I pretty-print the output?	`out, _ := json.MarshalIndent(v, "", " ")`.

JSON to Go Struct Converter: Online Go Generator

JSON to Go Struct Converter

JSON to Go Data Type Mapping Matrix

Golang Struct Tag Configuration Matrix

Technical Q&A / FAQ Matrix

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