> ## Documentation Index
> Fetch the complete documentation index at: https://docs.smtpexpress.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Project Credentials

> Connect to the SMTP Express API using your project credentials.

An SMTP Express project functions like a dedicated mail server. This enables you to send (transactional and promotional) and also receive emails. Each project on SMTP Express is assigned three key credentials: a `Sender Address`, `Project ID`,  and `Project Secret`

> To find your credentials, navigate to Projects > Settings > Credentials.

<Frame>
  <img src="https://mintcdn.com/smtpexpress/wOFUI6kxlh4ASM7h/assets/images/credentials-01.png?fit=max&auto=format&n=wOFUI6kxlh4ASM7h&q=85&s=69450bef768ee1bbe3a0e529c3b48b6e" width="928" height="383" data-path="assets/images/credentials-01.png" />
</Frame>

***

## The Sender Address

Also known as the *From Address*, this is the email address used to send emails (literally). By default, a sender address is generated for every project in the format: `<project>@smtpexpress.email`.

This address can be used to send and receive emails through SMTP Express. Additionally, a project's sender address can be changed by either setting a more recognizable username or [connecting a domain](/essentials/domains) which replaces `smtpexpress.email` with your own domain.

***

## The Project Secret

Project secrets are essentially your API keys and they are to be sent as Bearer Tokens when making your API Requests like so:

```shell cURL theme={null}
curl -XPOST 'https://api.smtpexpress.com/send'
 -H 'Authorization: Bearer <INSERT_PROJECT_SECRET>'
```

Every project comes with a default secret that you can copy and use immediately. If you need to generate a new one, use the `Create Secret` button.

<Frame>
  <img src="https://mintcdn.com/smtpexpress/wOFUI6kxlh4ASM7h/assets/images/credentials-02.png?fit=max&auto=format&n=wOFUI6kxlh4ASM7h&q=85&s=b25e94eecee9db2f75f9c3c132c780bb" width="1270" height="534" data-path="assets/images/credentials-02.png" />
</Frame>

### Authorized Origins

To secure your project secrets from misuse, we require every project secret to declare an origin in the form of a domain name.

Example values are: `localhost`, `app-name.netlify.app`, `website.com`. Be sure to replace with your actual origin when setting it up. Requests made from domains that are not listed under a secret's authorized origins will be denied.

***

## The Project ID

The Project ID is a unique public identifier for your project. Unlike secrets, it is designed to be safe for client-side exposure and is restricted to a limited set of API actions. Currently, it is only used with [Presets](/send/presets).

To use the Project ID in API requests, send it as a Bearer Token:

```shell cURL theme={null}
curl -XPOST 'https://api.smtpexpress.com/send'
 -H 'Authorization: Bearer <INSERT_PROJECT_ID>'
```

***

## Next Steps

Now that you understand how to authenticate and send emails with SMTP Express, explore more features to enhance your integration.

<CardGroup cols={2}>
  <Card title="Connect your Domain" icon="link" href="/quickstart">
    Personalize your sender address to match your business website.
  </Card>

  <Card title="The Send API" icon="square-code" href="/api">
    Learn more about using the Send API to power your entire mailing activity.
  </Card>
</CardGroup>