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

# Apply Event

> Confidence has the concept of applying a flag, this means marking the flag as used by a user.

Confidence automatically generate Apply Events, which you can use out-of-the-box to create [Assignment Tables](/docs/how-to-guides/create-assignment-table).

## On-Access Apply

Client-Side SDKs automatically emit `apply` events to the Confidence backend once applications read a flag or a flag's property. This allows Confidence to track who was exposed to what variant and when.

<Note>
  The `apply` event is only generated for flags that are successfully evaluated (that is, default values returned due to errors don't generate `apply` events).
</Note>

<Note>
  The `apply` event reports which flag and variant the application read, but not which property the application has read from such variant's value.
</Note>

To avoid generating redundant data, as long as the flags' data returned from the backend for a user remains unchanged, only the first reading of flag's property generates an `apply` event.

The Mobile Providers (iOS and Android) stores `apply` events on disk until it can send them correctly, thus ensuring the apply data reaches the backend even if generated when there is no network available (assuming the device re-connects to the network before the user deletes the application).

## On-Resolve Apply

Server SDKs and Edge Resolvers generate `apply` data at resolve time. The SDKs then batch this data and send it to the Confidence backend in the background, on a cadence.

## Related Resources

<CardGroup cols={2}>
  <Card title="Confidence SDKs" href="/docs/sdks/introduction">
    Overview of available SDKs
  </Card>

  <Card title="Assignment Tables" href="/docs/metrics/assignment-tables">
    Configure assignment tracking
  </Card>

  <Card title="Create Assignment Table" href="/docs/how-to-guides/create-assignment-table">
    Set up assignment tables
  </Card>

  <Card title="Exposure" href="/docs/metrics/exposure">
    Understand experiment exposure
  </Card>
</CardGroup>