# effects

{% tabs %}
{% tab title="overmind/effects.ts" %}

```typescript
import { User, Item } from './state'

export const api = {
  async getUser(): Promise<User> {
    const response = await fetch('/user')

    return response.json()
  },
  async getItem(id: number): Promise<Item> {
    const response = await fetch(`/items/${id}`)

    return response.json()
  }
}
```

{% endtab %}
{% endtabs %}

Effects is really just about exposing existing libraries or create your own APIs for doing side effects. When these effects are attached to the application they will be tracked by the devtools giving you additional debugging information. By “injecting” the effects this way also open up for better testability of your logic.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://overmindjs.org/v23/api-1/effects.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.