# Terminology

App Integrations has a few terms that an app developer has to be familiar with. Most of the App Integration terms are very common English words or computing terms that have a specific meaning with the App Integration systems.

This section lists the most common terms along with what they mean in the App Integration echo system.

## Interpolations

Interpolation refers to embedding expressions into marked up text. By default, interpolation uses the curly braces `{` and `}` as delimiters. The value to be put into the interpolatable string is taken from the [session](https://docs.chatlayer.ai/support/glossary) in chatlayer. Let us consider the following session exists in a specific conversation in chatlayer.


```json
    {
        "id": "someId",  
        "foo": "barz",
        "baz": "base",
        "userName": "test-username"
    }
```

Then if we find the text `Welcome to chatlayer {userName}`. Then the text that will be shown is `Welcome to chatlayer test-username`.