Elm:
HTTPリクエストの送信

import Http
import Json.Decode as Decode

type Msg
    = GotData (Result Http.Error String)

getData : Cmd Msg
getData =
    Http.get
        { url = "https://api.example.com/data"
        , expect = Http.expectString GotData
        }

-- JSONデコーダの例
type alias Data =
    { id : Int
    , title : String
    }

dataDecoder : Decode.Decoder Data
dataDecoder =
    Decode.map2 Data
        (Decode.field "id" Decode.int)
        (Decode.field "title" Decode.string)

getDataWithDecoder : Cmd Msg
getDataWithDecoder =
    Http.get
        { url = "https://api.example.com/data"
        , expect = Http.expectJson GotData dataDecoder
        }