# Discussions

A discussion is a container for a collection of individual [comments](/api/smartsheet/openapi/comments) within a single thread. A discussion can exist on a [row](/api/smartsheet/openapi/rows) or a [sheet](/api/smartsheet/openapi/sheets).

In the UI, Smartsheet creates a discussion to contain each top-level comment and subsequent replies into a single thread.

Using the API, you can only add a comment to a discussion. If the discussion doesn't already exist, you must create it first.
A discussion is a collection of one or more comments, each of which may contain attachments.

<h2>Discussion Attachments</h2>

For details about working with the attachments within a discussion, see [Attachments](/api/smartsheet/openapi/attachments).
<h2>Discussion Comments</h2>

For details about working with a discussion's comments, see [Comments](/api/smartsheet/openapi/comments).