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

> ## Agent Instructions
> API requests use the base URL https://api.unusualwhales.com and require a bearer token in the `Authorization` header (`Authorization: Bearer <API_KEY>`). Create and manage API tokens at https://unusualwhales.com/dashboard/api.
> For live market data inside an AI tool, use the Unusual Whales MCP server at https://unusualwhales.com/public-api/mcp.
> Instructions for agents using Unusual Whales tools: https://unusualwhales.com/skill.md

# FlexOption.ExerciseStyle

> When the contract can be exercised.

Enum
values**2**
used by[FlexOption](/docs/kafka/types/FlexOption.md)

**Proto definition**

```protobuf schema.proto theme={null}
enum FlexOption.ExerciseStyle {
  AMERICAN = 0;
  EUROPEAN = 1;
}
```

## Values

The number on the right of each row is the protobuf enum number.

AMERICAN
0

Can be exercised on any business day through expiration.

EUROPEAN
1

Can be exercised only on the expiration date.