# Comments

> For the complete machine-readable documentation index, see [llms.txt](https://apidocs.chargebee.com/llms.txt).


Comments are additional information that you can add to your resources. Comments can be added to provide context for any operation that was performed.

When you make an API call on any resource eg., Subscriptions -> Change term end, you can add more context to that operation by calling the comments API as a follow up call.

Besides the user generated comments, Chargebee also generates "System" comments when a change for a resource happens at the backend. These comments are all read-only.

## Sample Comment

```json
{
  "added_by": "full_access_key_v1",
  "created_at": 1517505963,
  "entity_id": "__test__KyVnHhSBWm65N2rx",
  "entity_type": "subscription",
  "id": "cmt___test__KyVnHhSBWm69N2s4",
  "notes": "This is a test comment",
  "object": "comment",
  "type": "user"
}
```

## Comments attributes

## Input Parameters

- `id` (required, string, max chars=40)
  Unique identifier for the comment.

- `entity_type` (required, enumerated string)
  Type of the entity this comment generated for
  Possible enum values:
    - `customer`
      Entity that represents a customer
    - `subscription`
      Entity that represents a subscription of a customer
    - `invoice`
      Invoice description
    - `quote`
      Entity that represents a quote
    - `credit_note`
      Credit note description
    - `transaction`
      Entity that represents a transaction.
    - `plan`
      Entity that represents a subscription plan
    - `addon`
      Entity that represents an addon
    - `coupon`
      Entity that represents a discount coupon
    - `order`
      Entity that represents an order
    - `business_entity`
      Entity that represents item of type business entity

- `added_by` (optional, string, max chars=100)
  The user who created the comment. If created via API, this contains the name given for the API key used.

- `notes` (required, string, max chars=1000)
  Actual notes for the comment.

- `created_at` (required, timestamp(UTC) in seconds)
  The time at which this comment was created

- `type` (required, enumerated string, default=user)
  Type of comment this is.
  Possible enum values:
    - `user`
      Comment generated by user either via API or Admin console.
    - `system`
      Comment generated by Chargebee when any backend changes happen for an entity

- `entity_id` (required, string, max chars=100)
  Unique identifier of the entity.

- `business_entity_id` (optional, string, max chars=50)
  The ID of the business entity created for the site. For Product Catalog 1.0, all the site data is tied to this business entity.
  
  **Note** [Multiple Business Entities](/docs/api/business_entities) is a feature available only on Product Catalog 2.0.