# Identifying users
[Guest users](#user-content-fn-1)[^1] can be identified when you first load the Frill Script, or at any time using the `identify` command.
**Important**
* You must provide a valid email.
* Name is optional but recommended
* Guest authentication will fail if:
* Your Widget/Survey has user/password or SSO authentication enabled
* The email is associated to an existing user/password account
The simplest way to identify users is with the `container` command. Just define the user as part of your configuration. We recommend identifying with an [SSO token](#sso) when possible as it circumvents any possibe edge cases (see above) that come with guest authentication.
```js
window.Frill('container', {
key: 'YOUR_SCRIPT_KEY',
user: {
email: 'email@domain.com',
name: 'my user', // optional
// You can also pass custom variables (attributes and companies) when identifying users
// attributes: { mrr: 100 },
// companies : [{ id: 'frill', name: "Frill.co" }] }
},
});
```
### `Frill('identify')`
If your app has client side authentication, you can identify the user using the `identify` command when they login. The `identify` command will identify the user for all active (and future) Widgets & Surveys.
```js
await window.Frill('identify', {
email: 'email@domain.com',
name: 'my user'
// You can pass custom variables here too...
// attributes: { mrr: 100 },
// companies : [{ id: 'frill', name: "Frill.co" }] }
});
```
If the user logs out, you should unidentify them:
```js
await window.Frill('unidentify');
```
### Single Sign On (SSO)
You can identify SSO users by passing a signed SSO JWT instead of user details. Your company does not need to enable SSO in the platform for this to work.
```typescript
window.Frill('container', {
key: 'YOUR_SCRIPT_KEY',
ssoToken: 'SSO_JWT_FROM_SERVER',
})
// Or with the identify command
await window.Frill('identify', { ssoToken: 'SSO_JWT_FROM_SERVER' });
```
[Check out this guide for more information on setting up SSO](https://developers.frill.co/single-sign-on/quick-start)
### Custom attributes
Custom attributes are a powerful way to segment your users inside of Frill. You can pass custom attributes when you identify users, just include an `attributes` and/or `companies` object alongside the user details.
{% hint style="info" %}
You must turn on the "**Allow custom attributes when identifying users with JS**" option from the Frill Script setup identification settings. If you're using SSO you will need to add the attributes as part of the token payload. [**Check out this guide**](https://help.frill.co/article/204-adding-custom-user-attributes-for-segmentation) for more information.
{% endhint %}
```typescript
await window.Frill('identify', {
email: 'email@domain.com',
name: 'my user'
attributes: { mrr: 100, job_title: 'CEO', free_user: false },
companies : [{ id: 'frill', name: "Frill.co" }] }
});
```
### iFrames
If you're loading your Widget in an iFrame you can still identify users (including SSO) by passing the user details as a query parameter.
#### **Guest users**
You can authenticate guest users by passing their details as the `user` query parameter. The object should be encoded and must have a valid email.
```javascript
// In javascript you would do
const user = encodeURIComponent(JSON.stringify({ name: 'Mitch Guest', email: 'mitch+guest@frill.co' }))
// And it should look like this
// %7B%22name%22%3A%22Mitch%20Guest%22%2C%22email%22%3A%22mitch%2Bguest%40frill.co%22%7D
```
```html
// Then load the Widget iframe
// It also works for Surveys
```
#### SSO users
To identify SSO users in an iFrame, pass your signed SSO JWT as the `ssoToken` query parameter.
```
// Then load the Widget iframe
// It also works for Surveys
```
[^1]: Your widget (or company) must have Guest or Anonymous authentication enabled for this to work.