# Leap.new

> Add email sending with SendDart to a Leap.new project using an Infrastructure secret.

[Leap](https://leap.new) is a platform for building full-stack web and mobile apps via chat.

## 1. Ask Leap to add SendDart

Add SendDart to a Leap project by asking the chat to add email sending with SendDart.

### Example prompt

```text
When someone fills out the contact form, send an email using SendDart.
```

## 2. Add your SendDart API key

Create a SendDart API key in the [dashboard](https://www.senddart.com/docs/api-keys/overview). Leap prompts you to set a secret value on the **Infrastructure** page — paste your key (e.g. as `SENDDART_API_KEY`) and click **Update secret**. In Node.js projects, Leap can use the official `senddart` SDK (`npm install senddart`) and call `mb.emails.send(...)`. In other runtimes, the generated backend calls the SendDart Emails API over plain HTTP.

> **Warning:** Do not share your API key or expose it in client-side code. Store it as a Leap Infrastructure secret.

## 3. Add a custom domain

By default you can only send email to your own address. To send to other recipients, [add and verify a custom domain](https://www.senddart.com/docs/add-a-domain), then update the `from` field in the send code to use an address on that domain (or ask the chat to update it).