These parameters may exist in all events.  


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Become familiar with the [event parameters which are denylisted](/docs/assets/events/introduction-to-events#denylist-of-event-parameters) by default for every workspace. These parameters are still available on the Raw data tab [in event details](/docs/crm/crm-profile#activity-list), if the data is available.

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## Base parameters

| Name | Type | Example | Description |
| --- | ---| --- | --- |
| action | string |`page.visit` | Type of the event. |
| ip | string | `13.93.68.194` | IP of the device that sent the event. |
| clientId  | integer | `5092159999` | Unique identifier of the profile. |
| eventUUID | string | `b26ba826-728d-46d2-8055-2c46ce9829f3` | Unique identifier of the event. |
| uuid | string | `e0097757-d1e2-44ac-ba3c-d97979a354c1` | UUID of the profile. When multiple profiles are merged into one, the old profiles are deleted, but their UUIDs are saved in the new profile. The profile UUIDs stored in pre-merge events are used to associate those events with the post-merge profile. |
| source | string | `WEB_DESKTOP` | The type of traffic source of the event. Possible values: `WEB_DESKTOP`, `MOBILEWEB`, `MOBILE_APP` |
| time | integer| `1669725368520` | Time when the event occurred, as a Unix timestamp including milliseconds. This is the time needed for [overwriting events](/developers/api/events/overwriting-events) (needs to be converted into ISO first). <ul><li>If the event didn't have a specified time when it was sent, `time` is the time when the event was received by Synerise</li><li>If the event had a future time specified when it was sent, that time is rejected and `time` is the time when the event was received by Synerise.</li></ul> |
| createDate | integer | `1669725368520` | Same as `time` |
| eventCreateTime | string | `2022-11-29T12:36:06.682Z` | Time when the event was received by Synerise. Does not exist in events generated by the system. |
| snr-original-time | string | `2048-10-05T15:25:06.459+02:00` | Original time that was sent with the event, even if it was rejected. Does not exist in events generated by the system. |
| label | string | `string` | This is a legacy parameter saved in raw data and some APIs/SDKs require sending it, but it's not saved into persistent storage. You can't use it in analytics. It may be removed in the future. |
| Custom parameters | any | `foo` | When importing events or sending them through the APIs/SDKs, you can add free-form custom parameters. They can also be added by [event enrichment](/docs/assets/events/adding-event-parameters#enriching-events-with-data-from-catalogs). |

## Parameters added by Web SDK

Some of the events may be sent from a website or an email by using the Synerise Web SDK. In those events, the following parameters may be added:

| Parameter | Type | Example | Description |
| --- | --- | --- | --- |
| tracker | string | `B264B70A-42D8-B6B7-13E5-ACAAAAAAA59` | Tracking code used to record this event |
| tablet | boolean | `true` | Informs if the event occurred on a tablet |
| mobile | boolean | `true` | `true` if the event occurred on a mobile device |
| URL/url | string | `https://www.shop.pl/gaming/consoles/worse-than-pc-256gb-white?gclid=EAIaIQobChMIo66d4564th547AYASAAEgI_MvD_BwE` | URL of the site where the event occurred |
| uri | string | `sub-domain.domain.com/path?gclid=EAIaIQobChMIo66d4564th547AYASAAEgI_MvD_BwE` | URI of the page where the event occurred |
| host | string | `sub-domain.domain.com` | Domain name or IP address of URL |
| location | string | `/eu-projects` | Resource location |
| ua.os.family | string | `Mac OS X` | Operating system of the source device |
| ua.os.major | string | `10` | Major version of the user's operating system |
| ua.os.minor | string | `12` | Minor operating system version number |
| ua.device.family | string | `Other` | The client device family |
| ua.device.brand | string | `Brandname` | Brand name of the device. Only sent by mobiles and tablets. |
| ua.device.model | string | `Model 8` | Model of the device. Only sent by mobiles and tablets. |
| userAgent | string | `Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko)` | Information about the User Agent |
| ua.major | string | `605` | Major UA version number |
| ua.minor | string | `15` | Minor UA version number |
| ua.patch | string | `15` | The patch version of the User Agent |

## Parameters added by Mobile SDK

If an event is sent by using [declarative tracking](/developers/mobile-sdk/event-tracking#declarative-tracking) or [predefined events](/developers/mobile-sdk/event-tracking#predefined-event-list) with the Mobile SDK, the `os` parameter is added. It informs about the operating system of the mobile device.