# Create a Discord bot (/guides/ecosystem/discordjs) Related: [Build an app with Astro and Bun](/guides/ecosystem/astro.md), [Containerize a Bun application with Docker](/guides/ecosystem/docker.md), [Use Drizzle ORM with Bun](/guides/ecosystem/drizzle.md), [Use Gel with Bun](/guides/ecosystem/gel.md), [Build an HTTP server using Elysia and Bun](/guides/ecosystem/elysia.md), [Build an HTTP server using Express and Bun](/guides/ecosystem/express.md) Discord.js runs on Bun with no extra setup. This guide builds a bot that answers a `/ping` slash command: you register the command once, then start the bot and use it in your server. If this is your first bot, copy each block as you reach it. *** Create a folder for your bot and set it up with `bun init`. Pick the defaults when it asks. ```sh icon="terminal" title="terminal" terminal mkdir my-bot cd my-bot bun init ``` *** Add Discord.js to the project. ```sh icon="terminal" title="terminal" terminal bun add discord.js ``` *** Your bot needs its own account, which you create in Discord's developer portal. Open the [developer portal](https://discord.com/developers/applications), sign in, and create an **Application**. Inside it, open the **Bot** tab to create the bot user. Discord's [setup walkthrough](https://discordjs.guide/legacy/preparations/app-setup) has screenshots if you get lost. Copy two values from the portal: * The **token** on the **Bot** tab. It's the password your code uses to log in, so treat it like one and keep it to yourself. * The **Application ID** on the **General Information** tab. Discord uses it to tie your commands to this app. *** A bot can't do anything in a server until you invite it. In the portal's **OAuth2** section, generate an invite URL with the `bot` and `applications.commands` scopes, open it, and add the bot to a server you manage. Slash commands need the `applications.commands` scope, so don't skip it. A personal server you make for testing is the easiest place to start, and Discord's [guide to adding a bot](https://discordjs.guide/legacy/preparations/adding-your-app) walks through it with screenshots. *** You also need your server's ID to register the command there. In Discord, turn on **Settings > Advanced > Developer Mode**, then right-click your server's icon and choose **Copy Server ID**. *** Save all three values in `.env.local`. Bun reads this file on startup and loads it into `process.env`, so nothing secret lives in your code. ```ini icon="settings" title=".env.local" DISCORD_TOKEN=your-bot-token DISCORD_CLIENT_ID=your-application-id DISCORD_GUILD_ID=your-server-id ``` *** Add `.env.local` to your `.gitignore` before you commit anything. Anyone who reads the token can control your bot, so it should never land in version control. ```txt icon="file-code" title=".gitignore" node_modules .env.local ``` *** Discord has to know about a command before anyone can use it. Register `/ping` with a short script named `deploy-commands.ts`. ```ts icon="/icons/typescript.svg" title="deploy-commands.ts" import { REST, Routes, SlashCommandBuilder } from "discord.js"; const { DISCORD_TOKEN, DISCORD_CLIENT_ID, DISCORD_GUILD_ID } = process.env; if (!DISCORD_TOKEN || !DISCORD_CLIENT_ID || !DISCORD_GUILD_ID) { throw new Error("Set DISCORD_TOKEN, DISCORD_CLIENT_ID, and DISCORD_GUILD_ID in .env.local"); } // the commands you want to register const commands = [new SlashCommandBuilder().setName("ping").setDescription("Replies with Pong!").toJSON()]; const rest = new REST().setToken(DISCORD_TOKEN); // register them in your test server await rest.put(Routes.applicationGuildCommands(DISCORD_CLIENT_ID, DISCORD_GUILD_ID), { body: commands }); console.log("Registered /ping"); ``` Run it once. ```sh icon="terminal" title="terminal" terminal bun run deploy-commands.ts ``` You only run this again when you add a command or change its name or description, not every time the bot starts. Registering to your server instead of globally keeps the command scoped to where you're testing. *** Now the bot itself. Save it as `bot.ts`. ```ts icon="/icons/typescript.svg" title="bot.ts" import { Client, Events, GatewayIntentBits } from "discord.js"; const { DISCORD_TOKEN } = process.env; if (!DISCORD_TOKEN) { throw new Error("Set DISCORD_TOKEN in .env.local"); } const client = new Client({ intents: [GatewayIntentBits.Guilds] }); // runs once, right after the bot connects client.once(Events.ClientReady, readyClient => { console.log(`Logged in as ${readyClient.user.tag}`); }); // runs every time someone uses a slash command client.on(Events.InteractionCreate, async interaction => { if (!interaction.isChatInputCommand()) return; if (interaction.commandName === "ping") { await interaction.reply("Pong!"); } }); client.login(DISCORD_TOKEN); ``` The ready handler logs a line once the bot connects. After that, `interactionCreate` runs whenever someone uses a slash command; it confirms the command was `/ping` and replies with `Pong!`. *** Start the bot with `bun run`. ```sh icon="terminal" title="terminal" terminal bun run bot.ts ``` The first connection takes a few seconds. Once the login line prints, switch to Discord and type `/ping` in your server. ```txt Logged in as my-bot#1234 ``` The bot replies with `Pong!`. You've got a working Discord bot. *** To add another command, define it in `deploy-commands.ts`, run that script again, and add an `if` branch for its name in `bot.ts`. The [Discord.js docs](https://discord.js.org/docs) cover command options, permissions, buttons, embeds, and the rest of the API. *** When you deploy, there's no build or bundling step. Bun runs `bot.ts` and every file it imports directly, so you ship your source as-is and start it with the same `bun run bot.ts` you use while developing. `deploy-commands.ts` registers `/ping` in your test server, which is the right scope while you're building. To publish the bot to every server it joins, register globally instead: change the route to `Routes.applicationCommands(DISCORD_CLIENT_ID)`. Global registration doesn't use a server, so you can also drop `DISCORD_GUILD_ID` from the script's check and from `.env.local`. To keep the bot online and bring it back after a crash or reboot, run it under a process manager. Run your bot as a Linux daemon Manage your bot with PM2