# Tag Types

Tag management APIs are classified as the APIs for one-dimensional (1D) tags and the APIs for two-dimensional (2D) tags.

- A 1D tag contains a string. All APIs for 1D tags are native OpenStack APIs. For details, see section Tag Management.
- A 2D tag consists of a key and a value. All APIs for 2D tags are ECS APIs. For details, see this section.

- Use the APIs of the same type to add, delete, modify, or query tags.
- 2D tags are recommended.

Parent topic: Tag Management