# Variables

Variables are a super-power of Octopus. They’re usually a high-risk deployment task, but Octopus makes it easy to manage and apply the correct values during a deployment. Using variables in Octopus, you can use the same deployment process across your environments and eliminate hard-coded configuration settings.

:::figure
![Adding a variable](/docs/img/projects/variables/images/project-variables.png)
:::

Octopus can manage simple values, secrets, and accounts as variables.

You can scope variables by:
- Environments
- Deployment target tags
- Deployment targets
- Deployment processes and steps
- Channels

Common examples include setting a different database connection string for each tenant or applying different logging levels by environment.

## Variable Sets

It's common to have variables that you need to use across multiple projects. Variable Sets make it possible to define a variable once and use it in many projects in the same space.  This is far simpler than duplicating a value in multiple projects.

You can scope variable sets to:
- Environments
- Deployment target tags
- Deployment targets

Each time you add a variable, consider whether you should place it in a variable set so all projects can share it.

## Learn more

- [Getting started with variables](/docs/projects/variables/getting-started)
- [Variable substitutions](/docs/projects/variables/variable-substitutions)
- [Variable filters](/docs/projects/variables/variable-filters)
- [System variables](/docs/projects/variables/system-variables)
- [Output variables](/docs/projects/variables/output-variables)
- [Prompted variables](/docs/projects/variables/prompted-variables)
- [Sensitive variables](/docs/projects/variables/sensitive-variables)