In Angular, pipes are a way to transform data in the template before displaying it. Pipes take in data as input and output transformed data to the template. Pipes can be used to format strings, format dates, perform calculations, filter data, and more.

Pipes can be used with interpolation, property binding, and the async pipe. Pipes can also be chained together to perform multiple transformations on the data.

Angular provides several built-in pipes, including:

DatePipe: This pipe is used to format dates.

UpperCasePipe: This pipe is used to convert text to uppercase.

LowerCasePipe: This pipe is used to convert text to lowercase.

CurrencyPipe: This pipe is used to format currency values.

PercentPipe: This pipe is used to format percentage values.

SlicePipe: This pipe is used to select a subset of an array.

AsyncPipe: This pipe is used to subscribe to an Observable and return the latest value.

In addition to the built-in pipes, developers can create custom pipes by implementing the PipeTransform interface. Custom pipes can be used to perform any type of transformation on the data.

Pipes in Angular are a powerful feature that allows developers to easily format and transform data in the template. They help in creating a more user-friendly interface and reduce the amount of logic needed in the component.