Real-world clock for ComputerCraft

-- Needs this API in order to work: https://pastebin.com/4nRg9CHU
os.loadAPI("json")
local monitor = peripheral.wrap("left")
monitor.setBackgroundColor(colors.black)

while true do
    monitor.clear()
    monitor.setCursorPos(1, 2)
    monitor.setTextColor(colors.lime)
    monitor.setTextScale(4)

    local apiString = http.get("http://worldtimeapi.org/api/ip").readAll()
    local apiObject = json.decode(apiString)

    local timeString = apiObject.datetime:sub(12, 16)

    monitor.write(timeString)
    sleep(30)
end