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

# Tags

> Read, add and remove visitor tags from a backend script — the same tags the Tag User and Has Tag funnel nodes use.

Tags mark a visitor so a later page or funnel step can branch on them: `seen_vsl`, `declined_upsell`, `vip`. Backend scripts get four functions for working with the same tags the [Tag User and Has Tag nodes](/funnels/page-events-nodes) set and read.

```javascript theme={null}
if (!hasTag('seen_offer')) {
  addTag('seen_offer', 10080); // 7 days
  setVariable('first_visit', true);
}
```

## `hasTag(name)`

Returns `true` if the visitor carries the tag, `false` otherwise. Finds tags set by the Tag User node, by `ef.addTag()` in the browser, and by `addTag()` below.

```javascript theme={null}
if (hasTag('vip')) {
  setVariable('discount', 20);
}
```

## `addTag(name, expirationMinutes?)`

Adds a tag. Returns `true` if it was added, `false` if the name was rejected or the per-execution cap was hit.

| Parameter           | Type   | Default | Description                                                                                   |
| ------------------- | ------ | ------- | --------------------------------------------------------------------------------------------- |
| `name`              | string | —       | Tag name. Letters, digits, `_`, `-`, `.`, `:`; max 120 characters                             |
| `expirationMinutes` | number | —       | Omit or pass `0` for a session tag; a positive number expires the tag after that many minutes |

```javascript theme={null}
addTag('abandoned_cart');           // until the browser session ends
addTag('trial_started', 10080);     // 7 days
addTag('promo_seen', 60);           // 1 hour
```

## `removeTag(name)`

Removes a tag. Returns `true` if the removal was queued, `false` if the name was rejected. Removing a tag the visitor does not have is not an error.

```javascript theme={null}
removeTag('abandoned_cart');
```

## `getTags()`

Returns an array of the visitor's tag names.

```javascript theme={null}
setVariable('tag_count', getTags().length);
```

<Note>
  `getTags()` lists tags written by `addTag()` and by `ef.addTag()` in the browser. Tags written by the **Tag User** node are stored under a bare cookie name that is indistinguishable from any other cookie, so they cannot be enumerated — `hasTag('name')` still finds them.
</Note>

## Reserved and invalid names

`addTag()` and `removeTag()` return `false` without doing anything when the name is empty, longer than 120 characters, contains characters that are not valid in a cookie name (spaces, `;`, `=`), or collides with a reserved cookie such as `hop`, `subid`, `aff` or the session cookie. This stops a tag from overwriting affiliate or session state.

```javascript theme={null}
addTag('hop');          // false — reserved
addTag('my tag');       // false — space is not a valid cookie-name character
addTag('cart_started'); // true
```

## A tag is visible immediately

A tag added by a backend script is visible to the rest of that same script, and to funnel nodes that run after it on the same request:

```javascript theme={null}
addTag('qualified');
hasTag('qualified'); // true — right away
```

<Warning>
  The **Tag User** node behaves differently: a tag it sets is only visible to a **Has Tag** node on the *next* request, not the one it was set on. If you need set-then-branch inside a single page load, set the tag with `addTag()` in a backend script rather than with a Tag User node.
</Warning>

## How tags are stored

Tags are plain, unencrypted cookies. Two naming conventions exist for historical reasons:

| Written by                  | Cookie name              |
| --------------------------- | ------------------------ |
| **Tag User** node (server)  | `vip`                    |
| `ef.addTag()` (browser)     | `tag_vip`                |
| `addTag()` (backend script) | both `vip` and `tag_vip` |

`addTag()` writes both names so a tag set from a backend script is visible everywhere — the Has Tag node, `ef.hasTag()` in the browser, and the `tags` array in Script Rules. `hasTag()` and `removeTag()` accept either spelling, so you do not have to think about which side set a tag.

<Warning>
  Because tags are unencrypted cookies, a visitor can add or remove their own tags from the browser console. Use them for funnel flow and personalization — never as the only gate on paid content, pricing, or anything else where forging a tag would cost you.
</Warning>

## Example: one-time offer

Show an offer once, then never again for 30 days.

```html theme={null}
<script scope="backend">
if (hasTag('flash_offer_seen')) {
  setVariable('show_offer', false);
} else {
  addTag('flash_offer_seen', 43200); // 30 days
  setVariable('show_offer', true);
}
</script>
```

## Example: clearing a tag after purchase

```html theme={null}
<script scope="backend">
if (is_customer && hasTag('abandoned_cart')) {
  removeTag('abandoned_cart');
  queue.cancel('abandon:' + customer.email);
}
</script>
```

See [Queue](/backend-scripts/queue) for the cancellation tag used here — that is a job-grouping label, unrelated to visitor tags.

## Limits

* **50** tag writes per script execution. `addTag()` and `removeTag()` return `false` past that.
* Each `addTag()` and `removeTag()` emits an `add-tag` / `remove-tag` tracking event, the same as the Tag User node and `ef.addTag()`.