# Concepts

Here we explain concepts in the context of wallets and how things are interconnected.

## How the types of pass classes are organized

Or how stereotype and pass types are organized and define the data models of the pass classes.

```{todo}
Define term stereotype - but not as glossary term only, better at own or at a concept page!
What is the difference to a pass type?
```

## How wallet apps, wallet providers, and host card emulation are connected

```{todo}
Distinguish between the Wallet Apps, the Wallet Pass APIs and the HCE/ OEM passes. Refine the section above. We may need an own section explaining the universe we are addressing here.
```