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

# Change event limits

In addition to using Chronosphere Observability Platform, you can use the
[CreateEvent API](/tooling/api-info/data_definition/operations/CreateEvent)
to create change events. This API can ingest 300 change events per minute, per block
in a single tenant. The total request size must be less than 1 MB.

## Change event fields

The CreateEvent API accepts the following fields with the stated limits:

| Field            | Description                                                                            | Required | Validation                                                                                                                                                     | Configurable        | Failure |
| ---------------- | -------------------------------------------------------------------------------------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------- | ------- |
| `title`          | Brief description of the change event.                                                 | Yes      | Maximum of 100 characters.                                                                                                                                     | No                  | Error   |
| `source`         | Identifies where the data originated.                                                  | Yes      | Maximum of 50 characters.                                                                                                                                      | No                  | Error   |
| `category`       | Informs Observability Platform about the kind of change event.                         | Yes      | Must be one of:<br />`"alerts"`<br />`"broadcasts"`<br />`"chronosphere"`<br />`"deploys"`<br />`"feature_flags"`<br />`"infrastructure"`<br />`"third_party"` | Yes                 | Error   |
| `happened_at`    | Indicates when the change event occurred, which defaults to `now` if unset.            | No       | Must be a Unix epoch timestamp.<br /><br />Can be set only to 24 hours before or after the current time.                                                       | Yes, with a restart | Error   |
| `type`           | Differentiates change events within a particular `category` or `source`.               | Yes      | Maximum of 50 characters.                                                                                                                                      | No                  | Error   |
| `labels`         | Key values associated with a change event.                                             | No       | Maximum of 200 labels (key/value pairs) per event.<br /><br /> - Keys: Maximum of 500 characters.<br /> - Values: Maximum of 5,000 characters.                 | No                  | Error   |
| `payload_json`   | Payload associated with a change event.                                                | No       | Maximum of 100,000 characters.                                                                                                                                 | No                  | -       |
| `payload_object` | Payload associated with a change event, if the original event was in key/value format. | No       | Maximum of 100,000 characters.                                                                                                                                 | No                  | -       |