> For the complete documentation index, see [llms.txt](https://docs.tonic.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tonic.ai/textual/entity-types/about-entity-types.md).

# About entity types

An entity type is a category of entity value. For example, the entity value John might be an example of the Given Name entity type.

Tonic Textual comes with a [built-in set of entity types that it always detects](/textual/entity-types/built-in-entity-types.md).

You can also configure custom entity types, which you can use to detect values that are not covered by the built-in entity types.

When you create a custom entity type, you can either:

* [Use regular expressions to identify matching values.](/textual/entity-types/entity-types-custom.md) You might create this type of custom entity when there are a limited number of values or the values follow specific formats that can easily be identified with a regular expression.
* [Define and train a model to identify matching values.](/textual/entity-types/entity-type-custom-model.md) Training a model is an iterative process that can take hours or days, depending on your data.\
  \
  You might create this type of custom entity when there are a large number of values that do not follow a specific format. The values need to be identified more by context.

You can also view this [video overview of entity types and entity type handling](https://youtu.be/05x8utCTYGY). 


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