Bun guide

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Prerequisites

• Setup a project in
• Ensure TypeScript is installed
• Create a Trigger.dev account
• Create a new Trigger.dev project

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Known issues

• Certain OpenTelemetry instrumentation will not work with Bun, because Bun does not support Node’s register hook. This means that some libraries that rely on this hook will not work with Bun.
• If Bun is installed via Homebrew (e.g. /opt/homebrew/bin/bun), you may see an ENOENT: spawn /Users/<you>/.bun/bin/bun error because the CLI expects Bun at the default install path. Workaround: create a symlink:
  mkdir -p ~/.bun/bin && ln -s $(which bun) ~/.bun/bin/bun
  
• Bun’s WebSocket client does not handle the 101 Switching Protocols upgrade response correctly, so connecting to a remote browser via puppeteer.connect() / playwright.connectOverCDP() (e.g. BrowserBase, Browserless) fails silently — typically with an empty {} ErrorEvent. The remote session opens and immediately drops. Workaround: set runtime: "node" in trigger.config.ts for tasks that connect to a remote browser.

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Initial setup

1

Run the CLI `init` command

The easiest way to get started is to use the CLI. It will add Trigger.dev to your existing project, create a /trigger folder and give you an example task.Run this command in the root of your project to get started:

npm

pnpm

yarn

npx trigger.dev@latest init --runtime bun

pnpm dlx trigger.dev@latest init --runtime bun

yarn dlx trigger.dev@latest init --runtime bun

It will do a few things:

1. Log you into the CLI if you’re not already logged in.
2. Create a trigger.config.ts file in the root of your project.
3. Ask where you’d like to create the /trigger directory.
4. Create the /src/trigger directory with an example task, /src/trigger/example.[ts/js].

Install the “Hello World” example task when prompted. We’ll use this task to test the setup.

2

Update example.ts to use Bun

Open the /src/trigger/example.ts file and replace the contents with the following:

example.ts

import { Database } from "bun:sqlite";
import { task } from "@trigger.dev/sdk";

export const bunTask = task({
  id: "bun-task",
  run: async (payload: { query: string }) => {
    const db = new Database(":memory:");
    const query = db.query("select 'Hello world' as message;");
    console.log(query.get()); // => { message: "Hello world" }

    return {
      message: "Query executed",
    };
  },
});

3

Run the CLI `dev` command

The CLI dev command runs a server for your tasks. It watches for changes in your /trigger directory and communicates with the Trigger.dev platform to register your tasks, perform runs, and send data back and forth.It can also update your @trigger.dev/* packages to prevent version mismatches and failed deploys. You will always be prompted first.

npm

pnpm

yarn

npx trigger.dev@latest dev

pnpm dlx trigger.dev@latest dev

yarn dlx trigger.dev@latest dev

4

Perform a test run using the dashboard

The CLI dev command spits out various useful URLs, including a link to the dashboard. Open it, find your Example task on the Tasks page, and press the “Test” button to open its test page.Most tasks have a “payload” which you enter in the JSON editor, but our example task doesn’t need any input. You can also configure run options, pre-populate the form from recent runs, and save run templates.Press the “Run test” button.

5

View your run

Congratulations, you should see the run page which will live reload showing you the current state of the run.If you go back to your terminal you’ll see that the dev command also shows the task status and links to the run log.