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

# Overview

> Personal hierarchical bookmark system for saving entities

## What Are Collections?

Collections are a personal bookmarking system built into Replyke. Each authenticated user has a private library of named folders — called collections — where they can save entities for later reference.

Collections are hierarchical: every user starts with a root collection and can create unlimited sub-collections nested inside it or inside each other.

<Note>Collections are private. They belong to and are only visible to the user who created them.</Note>

## How It Works

1. **Root collection** — automatically created the first time a user accesses their collections. Acts as the top-level folder and cannot be renamed or deleted.
2. **Sub-collections** — folders created inside the root or inside other sub-collections. Can be renamed and deleted.
3. **Entities** — saved into the current collection. The same entity can appear in multiple collections.

## Hooks

<CardGroup cols={2}>
  <Card title="useCollections" href="/hooks/collections/use-collections">
    Navigate the collection hierarchy and perform CRUD operations on the current collection context.
  </Card>

  <Card title="useCollectionsActions" href="/hooks/collections/use-collections-actions">
    Lower-level actions for fetching, creating, updating, and deleting collections.
  </Card>

  <Card title="useCollectionEntitiesWrapper" href="/hooks/collections/use-collection-entities-wrapper">
    Fetch paginated entities saved in a specific collection with sort and load-more support.
  </Card>
</CardGroup>

<Note>
  To check whether a specific entity is saved in any of the user's collections, see [useIsEntitySaved](/hooks/entities/use-is-entity-saved) in the entities section.
</Note>

## Data Model

See [Collection](/data-models/collection) for the full field reference.