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

# Auto-Captured Fields

> Fields captured automatically by the Upstack Pixel — click IDs, UTMs, device info, geo, and context. Don't set these manually.

These fields are captured automatically by the Upstack Pixel and edge API. **Do not include them in your `track()` calls.**

## Click IDs

Click IDs are captured automatically from URL parameters and browser cookies. Each platform's click ID is stored along with a timestamp indicating when it was collected.

### Meta (Facebook/Instagram)

| Field    | Source        | Description                                                  |
| -------- | ------------- | ------------------------------------------------------------ |
| `fbc`    | `_fbc` cookie | Meta click ID cookie (contains `fbclid` from ad click URL)   |
| `fbp`    | `_fbp` cookie | Meta browser ID (first-party cookie for user identification) |
| `fbclid` | URL parameter | Meta click ID from ad click URL (raw parameter value)        |

### Google Ads

| Field    | Source        | Description                                          |
| -------- | ------------- | ---------------------------------------------------- |
| `gclid`  | URL parameter | Google click ID (standard web campaigns)             |
| `gbraid` | URL parameter | Google click ID for iOS App campaigns (privacy-safe) |
| `wbraid` | URL parameter | Google click ID for web-to-app measurement           |

### TikTok

| Field    | Source        | Description                                         |
| -------- | ------------- | --------------------------------------------------- |
| `ttclid` | URL parameter | TikTok click ID from ad click URL                   |
| `ttp`    | `_ttp` cookie | TikTok browser ID cookie (first-party pixel cookie) |

### Snapchat

| Field              | Source         | Description                           |
| ------------------ | -------------- | ------------------------------------- |
| `snapchatSCCid`    | URL parameter  | Snapchat click ID (`ScCid` parameter) |
| `snapchatSCCookie` | `_scid` cookie | Snapchat browser ID cookie            |

### Pinterest

| Field           | Source         | Description                                |
| --------------- | -------------- | ------------------------------------------ |
| `pinterestEpik` | `_epik` cookie | Pinterest click ID cookie (Enhanced Match) |

### AppLovin

| Field           | Source        | Description                                    |
| --------------- | ------------- | ---------------------------------------------- |
| `applovinAxwrt` | URL parameter | AppLovin attribution token (`axwrt` parameter) |
| `aleid`         | URL parameter | AppLovin click ID                              |

### Klaviyo

| Field        | Source        | Description                       |
| ------------ | ------------- | --------------------------------- |
| `kx`         | URL parameter | Klaviyo click ID from email links |
| `klaviyoCid` | URL parameter | Klaviyo campaign ID               |

### Sendlane

| Field         | Source        | Description                        |
| ------------- | ------------- | ---------------------------------- |
| `sendlaneCid` | URL parameter | Sendlane click ID from email links |

### Omnisend

| Field         | Source        | Description                        |
| ------------- | ------------- | ---------------------------------- |
| `omnisendCid` | URL parameter | Omnisend click ID from email links |

### Reddit

| Field        | Source             | Description                    |
| ------------ | ------------------ | ------------------------------ |
| `redditCid`  | URL parameter      | Reddit click ID from ad clicks |
| `redditUuid` | `_rdt_uuid` cookie | Reddit browser ID cookie       |

### Taboola

| Field   | Source        | Description                            |
| ------- | ------------- | -------------------------------------- |
| `tblci` | URL parameter | Taboola click ID from native ad clicks |

### Outbrain

| Field    | Source        | Description                             |
| -------- | ------------- | --------------------------------------- |
| `obclid` | URL parameter | Outbrain click ID from native ad clicks |

### NewsBreak

| Field    | Source        | Description                       |
| -------- | ------------- | --------------------------------- |
| `nbclid` | URL parameter | NewsBreak click ID from ad clicks |

### LinkedIn

| Field     | Source        | Description                                                 |
| --------- | ------------- | ----------------------------------------------------------- |
| `liFatId` | URL parameter | LinkedIn First-Party Ad Tracking ID (`li_fat_id` parameter) |

### Microsoft Advertising (Bing)

| Field     | Source        | Description                    |
| --------- | ------------- | ------------------------------ |
| `msclkid` | URL parameter | Microsoft Advertising click ID |

***

## UTM Parameters

Captured automatically from URL query string parameters:

| Field          | Description                                               |
| -------------- | --------------------------------------------------------- |
| `utm_source`   | Traffic source (e.g., `google`, `facebook`, `newsletter`) |
| `utm_medium`   | Marketing medium (e.g., `cpc`, `email`, `social`)         |
| `utm_campaign` | Campaign name or identifier                               |
| `utm_content`  | Ad or link variant for A/B testing                        |
| `utm_term`     | Paid search keyword                                       |

***

## Page Context

Captured automatically from the browser on every event:

| Field      | Description                                    |
| ---------- | ---------------------------------------------- |
| `host`     | Hostname of the page (e.g., `www.example.com`) |
| `path`     | URL path (e.g., `/products/widget`)            |
| `referrer` | Full referrer URL                              |
| `search`   | Query string (e.g., `?utm_source=google`)      |
| `title`    | Page title from `document.title`               |
| `url`      | Full page URL where the event fired            |

***

## Viewport & Device

Captured from the browser at page load:

| Field               | Description                                                  |
| ------------------- | ------------------------------------------------------------ |
| `viewportWidth`     | Browser viewport width in CSS pixels                         |
| `viewportHeight`    | Browser viewport height in CSS pixels                        |
| `pageHeight`        | Total scrollable page height in CSS pixels                   |
| `devicePixelRatio`  | Device pixel ratio (e.g., `2` for Retina displays)           |
| `device_type`       | Detected device type: `"mobile"`, `"desktop"`, or `"tablet"` |
| `client_user_agent` | Browser user agent string                                    |

***

## Browser Settings

| Field             | Description                                 |
| ----------------- | ------------------------------------------- |
| `locale`          | Browser locale (e.g., `en-US`)              |
| `timezone`        | Browser timezone (e.g., `America/New_York`) |
| `adBlockDetected` | `true` if an ad blocker was detected        |

***

## Geographic Data (from Cloudflare)

Captured server-side from Cloudflare's edge network:

| Field         | Description                                        |
| ------------- | -------------------------------------------------- |
| `country`     | ISO 3166-1 alpha-2 country code (e.g., `US`, `GB`) |
| `region`      | State/province name (e.g., `Texas`, `California`)  |
| `regionCode`  | ISO 3166-2 region code (e.g., `TX`, `CA`)          |
| `city`        | City name (e.g., `Austin`, `San Francisco`)        |
| `postalCode`  | Postal/zip code (e.g., `78701`)                    |
| `latitude`    | Latitude coordinate                                |
| `longitude`   | Longitude coordinate                               |
| `continent`   | Continent code (e.g., `NA`, `EU`, `AS`)            |
| `isEUCountry` | `"1"` if the country is in the EU                  |
| `timezone`    | IANA timezone (e.g., `America/Chicago`)            |

***

## Network Info (from Cloudflare)

| Field               | Description                                           |
| ------------------- | ----------------------------------------------------- |
| `asn`               | Autonomous System Number                              |
| `asOrganization`    | Organization that owns the ASN (e.g., `Google Cloud`) |
| `isBot`             | `true` if Cloudflare detects the request as a bot     |
| `client_ip_address` | Visitor's IP address (captured server-side)           |

***

## Session & Event Metadata

| Field              | Description                       |
| ------------------ | --------------------------------- |
| `event_id`         | Unique event ID for deduplication |
| `event_time`       | Timestamp (ISO 8601, UTC)         |
| `event_source_url` | Full URL where the event fired    |
| `session_id`       | Upstack session identifier        |
| `pixel_id`         | Your Upstack Pixel ID             |