# Data sources

A data source is an essential part of every pipeline as it provides the input data that enters the pipeline and is passed to the modifiers. The data source of the current pipeline appears under the Data source section of the pipeline editor as depicted in this screenshot. Most of the time you will work with the data source type External file, which imports the input data for the pipeline from one or more files stored on your local computer or a remote machine.

Data source | Description
--- | ---
External file | Reads the simulation data from an external file.
Python script pro | Runs a user-defined Python script function to generate a dataset.
LAMMPS script pro | Runs a user-defined LAMMPS script to generate a dataset.