> For the complete documentation index, see [llms.txt](https://docs.moojo.id/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.moojo.id/user-credentials/intro-to-credentials.md).

# Intro to credentials

### What is a credential?

A credential is a piece of user-related data that provides information about them. Credentials are private to the user; while you can freely add new credentials to any user, you cannot view credentials created by others.

Credentials are stored in the user’s **private vault**, encrypted**, secured, and fully owned by the user.** \
As an app or AI agent, you can [define your own credential scheme](/user-credentials/define-and-add-new-credentials.md), [assign credentials to users](/user-credentials/define-and-add-new-credentials.md#add-a-credential-to-a-user), and retrieve them as needed. However, to assess a user’s fit for a specific segment based on their credentials, you must calculate the fit score using the [dedicated API endpoint](/user-credentials/compute-user-fit-score.md).