# Email Authentication

In addition to providing full authentication capabilities, **Form.io** also provides a very robust method for Automatic Logins via Email. There are many use cases where Email Login is utilized including, but not limited to…

* Email Registrations (where they must click on a link in their email to register)
* Email Reset Password

{% hint style="info" %}
[**Click Here** ](/how/sso-email-token.md)for a walkthrough on how to integrate an SSO Email Token to authenticate your application user base using Form.io. 
{% endhint %}

To make this happen, there is a special token that can be added to the message of your email action and templates. This token will generate a special JWT token to log in the person who the email was addressed to. This token is defined as follows.

```
  [[token(data.email=user)]]
```

Which is defined as follows…

```
  [[token(LOOKUP_FIELD=LOOKUP_RESOURCE)]]
```

* **LOOKUP\_FIELD** - This is the field that is used to search for the record we wish to login. This works by taking the value provided in the Email To: Address and searching the resource with that value as that field.
* **LOOKUP\_RESOURCE** - This is the resource to lookup when establishing the token.

***Important Note*** - This will ONLY create a token if the persons email address that is being sent the email is found within the resource.

For example, lets say you have a Resource as ***Customer*** and a field within that resource called ***Email*** you wish to create a token for. Now lets say you wish to send an email to one of your customers to complete their registration via email. This may look like the following.

```
  To:      john@example.com
  From:    no-reply@form.io
  Subject: Register Now
  Message: Click here to complete your registration http://myapp.com/?token=[[token(data.email=customer)]]#register
```

This following email performs the following:

* Looks up **data.email=<john@example.com>** within the **customer** Resource.
* If a record is found, it generates a temporary token and replaces `[[token(data.email=customer)]]` with that token.
* Tells the application to navigate to the ***#register*** state once the authentication has been performed.

This turns this email into something that looks like the following.

```
  To:      john@example.com
  From:    no-reply@form.io
  Subject: Register Now
  Message: Click here to complete your registration http://myapp.com/?token=lkjsdlkjs90980982l3kjlkjslkjsd....#register
```

#### Application Changes to handle Email Tokens <a href="#application-changes-to-handle-email-tokens" id="application-changes-to-handle-email-tokens"></a>

Once you have the email being sent, this single sign on URL will direct them to the Serverless application which needs to handle the token. This requires a minor change within your application to accept the token and then reset the `localStorage` value with the new token. The **\<form.io>** library will then take it from there and authenticate all future requests with that token. You can make this change by adding the following to your ***/app/config.js*** file.

```javascript
// Parse query string
var query = {};
location.search.substr(1).split("&").forEach(function(item) {
  query[item.split("=")[0]] = item.split("=")[1] && decodeURIComponent(item.split("=")[1]);
});

// This is what you will need to add to your application.
if (query.token) {
  localStorage.setItem('formioToken', query.token);
  localStorage.removeItem('formioAppUser');
  localStorage.removeItem('formioUser');
  window.history.pushState("", "", location.pathname + location.hash);
}
```

Once you have implemented this, your application should then be able to handle an automatic email authentication into your application.


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