Local Development

You can run Inngest locally in a single command to build, test, and iterate locally, exactly as code runs on production. The Inngest Dev Server is a fully-featured and open-source local version of the Inngest Platform enabling a seamless transition from your local development to feature, staging and production environments.

The Dev Server records local events and function runs, so you can test steps, waits, retries, and errors before you deploy. The Dev Server also bundles in a full tracing UI and allows you to replay local and production functions to easily fix issues.

Running the dev server locally

curl -sSfL https://cli.inngest.com/install.sh | sh
inngest dev -u http://localhost:3000/api/inngest

If Homebrew blocks the tap as untrusted, run brew trust --cask inngest/tap/inngest and retry the install.

Connecting your Inngest functions

Start your app with INNGEST_DEV=1. This puts all SDKs in local development mode and sends its events to the Dev Server instead of the cloud.

INNGEST_DEV=1 npm run dev

If you run the Dev Server in a container, set INNGEST_DEV to its URL:

INNGEST_DEV=http://127.0.0.1:8288 npm run dev

Replace npm run dev with the command that starts your app. Open http://localhost:8288. The Apps page should show your app, and the Functions page should list its functions.

The Dev Server can discover common local ports and endpoint paths. The -u flag gives it the exact address and makes setup easier to check. You can connect more than one app by passing another -u URL.

AI-assisted local development

The Dev Server also exposes a local Model Context Protocol (MCP) integration at http://127.0.0.1:8288/mcp. Connect Claude Code, Cursor, or another MCP-compatible coding agent to list registered functions, send test events, invoke functions, and inspect run status while your app is running locally.

Use a local Connect worker

If your app uses connect() instead of an HTTP serve() endpoint, start the Dev Server and run the worker process with INNGEST_DEV=1. The worker connects to the Dev Server and syncs its functions automatically; you do not pass an HTTP -u URL for that worker. Local Connect requires no signing or event key. Keep the worker process running while you test. See the Connect local development guide for the worker setup and runtime requirements.

Test a function

Open Functions and select Invoke to call one function with a JSON payload. To test an event trigger, select Test Event and send a JSON event whose name matches the function's trigger. For example:

{
  "name": "ticket/created",
  "data": {
    "ticketId": "ticket-123"
  }
}

Open Runs and select the new run. Inspect the steps, output, errors, and trace. Change the payload or your function code, then run it again. The Dev Server polls your app for function changes.

You can also send an event from your application with inngest.send() while the app runs with INNGEST_DEV=1. If your app needs INNGEST_EVENT_KEY locally, the Dev Server accepts a dummy value. See Get started for a complete TypeScript v4 example that creates and tests a function.

Configuration file

If you use several options or connect multiple apps with -u, put them in an inngest.json file. The dev command searches the current directory and its parent directories for the file. It also supports yaml, yml, toml, and properties formats. Run inngest dev --help to list all options.

These examples configure two app URLs and disable auto-discovery:

{
  "sdk-url": [
    "http://localhost:3000/api/inngest",
    "http://localhost:3030/api/inngest"
  ],
  "no-discovery": true
}

Inngest SDK debug endpoint

Send a GET request to your app's SDK serve() endpoint to inspect its local configuration. Open the URL in a browser or use curl. For an app at http://localhost:3000/api/inngest, a response can look like this:

curl -s http://localhost:3000/api/inngest | jq

{
  "message": "Inngest endpoint configured correctly.",
  "hasEventKey": false,
  "hasSigningKey": false,
  "functionsFound": 1
}

Auto-discovery

The Dev Server detects apps on common ports and endpoint paths. To disable discovery and provide the serve() URL yourself, pass --no-discovery with -u:

npx --ignore-scripts=false inngest-cli@latest dev --no-discovery -u http://localhost:3000/api/inngest

Common endpoint paths:

/api/inngest
/x/inngest
/.netlify/functions/inngest
/.redwood/functions/inngest

Common ports include 80 and 443, 3000–3010 for Rails, Express, Next.js, Nuxt, and Nest, 5000 for Django, 5173 for Vite and SvelteKit, 8000, 8080, 8081, and 8888 for other apps, 8910–8915 for Redwood, and 8787 for Cloudflare Workers.

CLI flags

inngest-cli dev supports these flags:

If your functions do not appear

• Check that your app process is running and that the -u URL uses its actual port and path.
• Open the serve() URL in a browser, or run curl http://localhost:3000/api/inngest with your app's URL. Its diagnostic response should report that the endpoint is configured and show functionsFound.
• Check that you passed the app's serve() URL, not the Dev Server's http://localhost:8288 URL.

If events go to Inngest Cloud

Set INNGEST_DEV=1 on the app process and restart it. The TypeScript SDK defaults to cloud mode when you do not set a mode. If your Dev Server uses a different host or port, set INNGEST_BASE_URL in the app to its full URL, such as http://localhost:8290. Set these values on the app process, then restart it.

The Dev Server supports local development and testing. When you deploy, connect your app to its Inngest environment. For a function you can run locally now, continue with Get started.