Action Libraries
Action libraries are reusable transaction flows to create complex transactions that invoke several services, therefore speeding up the transactions building process. They can be used in as many transactions as necessary.
For example, you can have a transaction that validates an OTP, validates user and password, verifies products and asks for a balance detail. Each operation can be turned into an action library that can be invoked every time you need it in a different transaction.
Within the Action Library tab ( > Libraries > Action libraries) you see a list of all the action libraries created within the branch you are working on. To find an action library, use the search bar and search by name or description.

From this page, you can create an action library, which redirects you to the transactions editor. Hovering over an action library on the list displays additional actions:
You can edit the action library.
Caution
Editing an action library that is in use might affect the transaction that is invoking it.
You can verify an action library's dependencies. By doing this, you can verify if that action library is being used in one or more transactions or action libraries in the environment. A modal shows the code, name and product of the transactions where the action library is being used.
You can duplicate the action library.
You can delete an action library that is not being used; that is, it does not have any dependencies that may affect the transaction's functionality.
When there is one or more users working on the same action library you are working on, you will see a user icon with the number of users present in that entity. Hover over the icon to see who that user is. This number and list of users is updated in real time.

Concurrent Editing
Verifying if someone else is working on your entities is useful to prevent concurrency issues, such as loss of updates, since saving changes when another user is still working on the entity will make them lose any changes made.
Read Create an Action Library to learn more about this process, or Action Libraries in the Transactions section to learn how to use your action libraries within a transaction.