How to get the ID of a guild on join in Discord.js

I need the bot to get the guild ID on join for an api. At the moment I've tried this, but I get an error:

Cannot read property 'id' of undefined

My code

client.on("guildCreate", (guild) => {
  request(
    {
      url:
        "https://urlgoeshere" +
        client.guild.id +
        "/" +
        key +
        "/" +
        client.guild.memberCount,
    },
    function (error, httpResponse, body) {
      console.error("error:", error); 
      console.log("body:", body); 
    }
  );
});