Input JSON
Go Output
Structs generated in your browser
Paste a JSON sample and get clean Go structs with json tags — nested objects become their own structs, numbers infer to int64 or float64, and nullable fields become pointers. Fast, secure, and entirely in your browser.
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A JSON to Go converter reads a sample of JSON and writes the Go struct definitions that describe its shape, complete with the json struct tags Go's encoding/json package uses to marshal and unmarshal. Instead of hand-writing a struct for every API response, you paste the response and get a typed definition you can drop into your package.
Go needs a concrete type to unmarshal JSON into, and writing those types by hand for a large payload is slow and easy to get wrong, especially the json tags that map exported fields back to their lowercase keys. Generating them from a real sample means the tags and types match the data exactly.
[]string, []Item).These are the inference rules the converter applies so the output is predictable.
| JSON | Becomes in Go |
|---|---|
Object { } | A struct with one field per key. |
| Nested object | Its own named struct, referenced from the parent field. |
Array [ ] | A slice such as []string or []Item. |
| Whole number | int64. |
| Decimal number | float64. |
| string / boolean | string / bool. |
| null (with a value) | A pointer such as *int64, so nil is representable. |
| null only / mixed types | interface{} (or []interface{} for a mixed array). |
Every field gets a json tag using the original key, so UserID int64 `json:"userId"` round-trips correctly. When you paste an array of objects, a key missing from some items is marked optional with ,omitempty, and a field that is sometimes null becomes a pointer so nil is representable. Validate the JSON first with the JSON parser if it will not convert, or tidy it in the JSON formatter.
interface{}A field that is only ever null, an empty array, or holds more than one unrelated type has no single concrete Go type, so it falls back to interface{}. Paste a representative sample with those fields populated to get precise types, and prefer giving an array of several records so optional fields are detected. For a deeply nested payload, expanding it in the JSON viewer first helps you confirm the shape.
See how a nested object with an array of items becomes clean, tagged Go structs.
Notice three things: items became its own Item struct and a slice, Qty got ,omitempty because the second item omits it, and coupon is interface{} because the sample only ever shows null. For the step-by-step reasoning, see our guide on converting JSON to Go structs.
Typed structs from real data, in seconds.
Everything developers ask about generating Go structs from JSON.
json:"userId" using the original JSON key, so marshaling and unmarshaling round-trip correctly even though Go field names are exported in PascalCase.int64 and numbers with a decimal point become float64. If a field holds both across the sample, it widens to float64 so every value fits.,omitempty in its tag. A field that is sometimes null and sometimes a value becomes a pointer, such as *int64, so nil is representable.[]string or []Item, with the element type inferred from the items.interface{} (or []interface{} for a mixed array).gofmt or goimports afterwards keeps the file consistent with the rest of your project.Hands-on articles from our blog.
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