我的结构编码不正确，缺少属性

type ApiResponse struct {
    Success bool     `json:"success"`
    Errors  []string `json:"errors"`
}

type NewSessionResponse struct {
    ApiResponse     `json:"apiResponse"`
    authToken   string `json:"authToken"`
}

In my handler I am doing this:

resp := NewSessionResponse{ApiResponse{true, []string{}}, "auth123"}

json.NewEncoder(w).Encode(resp)

The response I am seeing is this:

{
    apiResponse: {
        success: true,
        errors: [ ]
    }
}

Why isn't my authToken property in the JSON result?

authToken filed is an unexported field. Json library does not have the power to view fields using reflect unless they are exported. A package can only view the unexported fields of types within its own package.

You can export the filed to get this working

type NewSessionResponse struct {
    ApiResponse     `json:"apiResponse"`
    AuthToken   string `json:"authToken"`
}

FYI: Exported identifiers https://golang.org/ref/spec#Exported_identifiers