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

# Hook Extensions

> Create server-side event hooks

Hooks allow you to execute custom code in response to Directus events.

## Creating a Hook

```bash theme={null}
npm init directus-extension
# Select "hook" as the extension type
```

## Hook Structure

```typescript theme={null}
import { defineHook } from '@directus/extensions-sdk';

export default defineHook(({ filter, action }, { services, getSchema }) => {
  // Filter hook - modify data before it's processed
  filter('items.create', async (input, meta, context) => {
    if (meta.collection === 'articles') {
      input.slug = input.title.toLowerCase().replace(/\s+/g, '-');
    }
    return input;
  });

  // Action hook - execute after an action completes
  action('items.create', async (meta, context) => {
    if (meta.collection === 'articles') {
      console.log('Article created:', meta.key);
    }
  });
});
```

## Event Types

### Item Events

* `items.create`
* `items.update`
* `items.delete`
* `items.promote`
* `items.sort`

### Authentication Events

* `auth.login`
* `auth.create`
* `auth.update`

### Server Events

* `server.start`
* `server.stop`

### Request Events

* `request`
* `response`

## Filter Hooks

Modify data before it's processed:

```typescript theme={null}
filter('items.create', (input, meta) => {
  // Modify input
  input.created_at = new Date();
  return input;
});
```

## Action Hooks

Execute code after an action:

```typescript theme={null}
action('items.create', async (meta, context) => {
  const { ItemsService } = context.services;
  const schema = await context.getSchema();
  
  const itemsService = new ItemsService('logs', { schema });
  await itemsService.createOne({
    action: 'create',
    collection: meta.collection,
    item: meta.key,
  });
});
```

## Context

Hooks receive context with:

```typescript theme={null}
interface Context {
  services: Services;
  getSchema: () => Promise<Schema>;
  database: Knex;
  accountability: Accountability | null;
}
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Operations" icon="diagram-project" href="/extensions/operations">
    Create flow operations
  </Card>

  <Card title="Endpoints" icon="code" href="/extensions/endpoints">
    Create API endpoints
  </Card>
</CardGroup>