> For the complete documentation index, see [llms.txt](https://docs.langstack.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.langstack.com/welcome/get-started/learn-langstack/introduction-to-etl-pipeline/shared-variables-for-etl-pipeline.md).

# Shared variables for ETL pipeline

When an ETL pipeline is created, a shared variable “StartupParameters” of the data type “List” is created by default. \
This variable may be used to take a value from the user on the ETL pipeline Run, and, based on the input, perform specific actions to a record before running the ETL pipeline.

<figure><img src="https://media.langstack.com/documentation/media/images/code/training_manual/chapter_9/ch9etlsharedvars.png" alt=""><figcaption></figcaption></figure>