JSON to Go Struct

A JSON to Go struct converter turns a JSON document into the Go type declarations that describe it, so you can unmarshal the same data with encoding/json instead of typing the struct by hand. Every JSON object becomes a Go struct, every field carries a json:"key" tag that maps it back to the original name, and the scalar types are inferred from the values: a JSON string becomes string, a whole number becomes int, a decimal becomes float64, true and false become bool, and null becomes interface{}. Paste a payload and you get a ready-to-compile type block back.

It exists because writing Go structs from a real API response is tedious and easy to get subtly wrong. Field names have to be exported and follow Go conventions, so id becomes ID and user_url becomes UserURL, while the json tag has to preserve the exact original key or json.Unmarshal silently skips the field. Nested objects need their own struct, and an array of objects needs a single struct that covers every key any element has. Doing that across a deeply nested response is where mistakes creep in. The converter applies these rules consistently: nested objects become inline structs, and arrays of objects are merged so a key that appears in only some elements is still present in the generated type.

Everything runs in your browser. The JSON you paste is parsed and analysed in JavaScript on your own device, so nothing is uploaded, logged, or stored, and the tool keeps working with the network disconnected once the page has loaded. That matters when the payload is a private API response or contains keys and values you would rather not send anywhere. You can rename the root type, switch integers to int64 when you need the wider type, and add omitempty to every tag when you want zero values omitted from the encoded output.

A short example shows the go JSON to struct mapping. Paste {"order_id": 1042, "total": 19.5, "items": [{"sku": "A1", "qty": 2}, {"sku": "B2", "qty": 1, "gift_note": "Happy birthday"}]}, type order as the Root type and click Convert. You get type Order struct with OrderID int, Total float64 and Items []struct holding Sku string, Qty int and GiftNote string. GiftNote is there even though only the second item has it, because the JSON to Go struct converter merges every element of the array into one type.