# Core Features

- [Core API Overview](/v3/core-features/core-api-overview.md): Elements supports a wide variety of APIs that provide core functionality such as login, sessions, In-App Purchases, inventory management, and more.
- [Sessions](/v3/core-features/sessions.md): Elements utilizes Sessions in order for the client application to securely communicate with Elements APIs.
- [Applications](/v3/core-features/applications.md): Elements allows the creation of Applications in a multi-tenant format - a suite of applications that communicate with the database across a single shared instance.
- [Users and Profiles](/v3/core-features/users-and-profiles.md): Elements fully supports Users and Profiles that allow users of your application or game to store their profile data and access a network of applications from a single login profile.
- [Digital Goods](/v3/core-features/digital-goods.md): Elements fully supports Digital Goods, which are items that can be owned by users in their inventory or purchased with In-App Purchases, such as potions or gold coins in a video game.
- [Progress and Missions](/v3/core-features/progress-and-missions.md): Elements allows the creation of Missions, in which users can make progress that is tracked in their user profile.
- [Leaderboards](/v3/core-features/leaderboards.md): Elements facilitates the creation of Leaderboards that can track user rankings and scores.
- [Matchmaking](/v3/core-features/matchmaking.md): Elements supports matchmaking for online gaming, including one vs one or group matches with teams.
- [Followers](/v3/core-features/followers.md): Elements allows online User profiles to build a following, which is a more loosely defined relationship between two profiles than Friends.
- [Friends](/v3/core-features/friends.md): Elements supports the concept of Friends between two users, which establishes a relationship that offers more engagement, such as viewing Leaderboard rankings or viewing each other's profile details.
- [Reward Issuance](/v3/core-features/reward-issuance.md)
- [Save Data](/v3/core-features/save-data.md): Elements allows saving data associated with Users and Profiles with multiple options to prevent conflicts using version control.
- [Schemas and Metadata Specifications](/v3/core-features/schemas-and-metadata-specifications.md)
- [Queries](/v3/core-features/queries.md): How to Write Boolean-Style Queries in Elements
- [Base Query Syntax](/v3/core-features/queries/base-query-syntax.md): Base Query Syntax
- [Boolean Queries](/v3/core-features/queries/boolean-queries.md): Combining Base Queries to Form Complex Queries
- [Object Graph Navigation](/v3/core-features/queries/object-graph-navigation.md): Understanding Object Graphs
- [Advanced Operators](/v3/core-features/queries/advanced-operators.md): Use Extensions to find Advanced Mappings
- [.ref](/v3/core-features/queries/advanced-operators/.ref.md): Specifies and Object Reference
- [.name](/v3/core-features/queries/advanced-operators/.name.md): Specifies an Object by Name
- [Custom Code](/v3/core-features/custom-code.md): Deploy custom code to your instance of Elements.
- [Element Structure](/v3/core-features/custom-code/element-structure.md): Here's where you learn to develop your first Element.
- [RESTful APIs](/v3/core-features/custom-code/restful-apis.md): How to build RESTful APIs in Elements
- [Websockets](/v3/core-features/custom-code/websockets.md): How to build Websocket APIs in Elements
- [Auth Schemes](/v3/core-features/auth-schemes.md)
- [OIDC](/v3/core-features/auth-schemes/oidc.md)
- [OAuth2](/v3/core-features/auth-schemes/oauth2.md): When creating a new Session, you have the option to authenticate using a predefined OAuth2 Auth Scheme.