> ## 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.

# Create Sub-Collection

> Create a new sub-collection inside an existing collection

Creates a new named sub-collection under the specified parent collection. Returns `400` if the parent collection does not exist.

## Path Parameters

<ParamField path="collectionId" type="string" required>
  The ID of the parent collection. Use the root collection's ID to create a top-level folder.
</ParamField>

## Body Parameters

<ParamField body="collectionName" type="string" required>
  The name for the new collection.
</ParamField>

## Response

Returns the newly created [Collection](/data-models/collection) object with `status 201`.

## Error Responses

<AccordionGroup>
  <Accordion title="Invalid Parent — 400 Bad Request">
    ```json theme={null}
    { "error": "Invalid parent collection ID for sub-collection", "code": "collection/invalid-parent" }
    ```
  </Accordion>

  <Accordion title="Server Error — 500">
    ```json theme={null}
    { "error": "Server error", "code": "collection/server-error" }
    ```
  </Accordion>
</AccordionGroup>