> ## Documentation Index
> Fetch the complete documentation index at: https://www.activepieces.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# External Libraries

> Learn how to install and use external libraries.

The Activepieces repository is structured as a monorepo, employing Nx as its build tool.

To keep our main `package.json` as light as possible, we keep libraries that are only used for a piece in the piece `package.json` . This means when adding a new library you should navigate to the piece folder and install the library with our package manager `bun`

```bash theme={null}
cd packages/pieces/<piece-path> 
bun install --save <library-name>
```

* Import the library into your piece.

Guidelines:

* Make sure you are using well-maintained libraries.
* Ensure that the library size is not too large to avoid bloating the bundle size; this will make the piece load faster in the sandbox.

## Dependency Pinning

When pieces are built for publishing, all dependency versions — including **transitive dependencies** (dependencies of your dependencies) — are automatically pinned to the exact versions resolved in the monorepo's `bun.lock` file.

This means:

* You don't need to worry about manually pinning transitive dependency versions.
* The published piece will always install the same dependency tree that was tested during development.
* This protects against supply chain attacks where a compromised transitive dependency could be silently pulled in at install time.