# Send user ids for known users

> Attach your own user id to events from the browser and from your servers, so signed-in people are followed across days and devices.

Source: https://docs.bifrostorbit.com/insights/developers/known-users/

Known users let Insights Orbit follow a signed-in person across days and devices, for funnels across days and for retention. They come with the Enterprise plan, and an Admin switches them on per site under **Site settings**, **Known users**. Ids sent to a site without it are dropped. See [Known users](https://docs.bifrostorbit.com/insights/everyone/known-users/) for what it means for your organisation.

## From the browser

Add `data-known-users` to the script tag. Without it, `insights.identify` does nothing:

```html
<script defer data-site="SITE_KEY" data-known-users src="https://api.bifrostorbit.com/insights/v1/script.js"></script>
```

Once someone has signed in, pass their id:

```js
window.insights?.identify('customer-1042');
```

Every page view and event after that carries the id. Call `identify(null)` when they sign out.

- The script keeps the id in memory only, never in the browser's storage, so call `identify` on every page load while the person is signed in. On a website that changes pages without reloading, once per load is enough.
- Ids can be up to 128 characters. Use an id that means nothing outside your systems, such as a customer number, never an email address.
- If your code may run before the script has loaded, queue the call: `window.insights = window.insights || { q: [] }; window.insights.q.push(['identify', 'customer-1042'])`.

`CmsInsights` in the CMS Orbit SDKs has no option for `data-known-users`. Use your own script tag on websites that send user ids.

## From a server

Add `userId` to each event you send to the [server API](https://docs.bifrostorbit.com/insights/developers/server-api/):

```json
{ "site": "SITE_KEY", "events": [{ "id": "order-1042", "name": "Order paid", "userId": "customer-1042", "revenue": 1240, "currency": "EUR" }] }
```

A funnel counted by known users can then start with a page view in the browser and end with a payment your server confirmed.

## What is stored

Insights Orbit never stores the id. It keeps `person`, a scrambled form made with a key that belongs to your organisation, the same for every event of that person. The [raw event API](https://docs.bifrostorbit.com/insights/developers/raw-event-api/), [GraphQL](https://docs.bifrostorbit.com/insights/developers/graphql/) and the [S3 export](https://docs.bifrostorbit.com/insights/developers/s3-export/) give `person`, never the id.

Admins can download or erase one person's events under **Known users**, by the id your website sends.