JSON to Go

Generate Go structs with json:"…" tags from a JSON sample. Each object becomes a struct, each key a Go-cased field (created_at → CreatedAt), and the JSON tag preserves the original key. Nullable values get pointer types (*string) so you can distinguish missing from zero-value. Powered by quicktype, runs entirely in your browser.

Paste JSON (or load the example) and read the Go struct on the right. Each nested object becomes its own type, with idiomatic Go field names and json: tags so the struct round-trips through encoding/json.

Input: {"id":42,"name":"devsmiths","createdAt":"2024-03-11T08:24:00Z","stars":1280,"public":true,"contributors":[{"login":"ada","commits":51,"admin":true},{"login":"linus","commits":33,"admin":false}],"homepage":null}

Output (Go):

type Root struct {
    ID           int64         `json:"id"`
    Name         string        `json:"name"`
    CreatedAt    string        `json:"createdAt"`
    Stars        int64         `json:"stars"`
    Public       bool          `json:"public"`
    Contributors []Contributor `json:"contributors"`
    Homepage     interface{}   `json:"homepage"`
}

type Contributor struct {
    Login   string `json:"login"`
    Commits int64  `json:"commits"`
    Admin   bool   `json:"admin"`
}

• Field names are PascalCase (Go’s requirement for exported fields), but the json:"…" tag preserves the original JSON casing — so created_at in JSON becomes CreatedAt string `json:"created_at"`.
• Nullable fields (where the sample has null) are emitted as interface, not pointer types. You usually want pointers (*string) to distinguish “missing” from “zero value”; flip nullable as pointer in the options pane if that matches your downstream code.
• Whole numbers are typed as int64 regardless of magnitude. If the JSON contains 2.0 the generator emits float64; if it contains 2 you get int64. encoding/json tolerates either at decode time, but tighten by hand for fields you know are always integral.
• Date strings (ISO 8601) generate as plain string, not time.Time. The generator can’t tell a date from a slug at the JSON layer — change the field type and add a UnmarshalJSON if you want native time values.
• No omitempty tags by default. Add them by hand for fields that should be skipped when serialising back to JSON (or pass all optional to get omitempty on every field).
• The single-sample limitation applies here too — fields not present in the sample need to be added by hand or via all optional.