The Optimizely Profile Store API is separated from the [Tracking API](🔗) so that it has independent processing loads.
Optimizely ships the API with [Swagger](🔗) documentation. Append **/swagger** to the root URL to access swagger documentation and test functionality. However, not all APIs are available for testing in production.
Tracking is based on the following concepts:
**[Track events](🔗)** – Data about user behaviors that the installed Optimizely Tracking package automatically collects, such as visiting a page, clicking a link, and so on. From time-to-time, track event analyzes and consolidates the data into a profile.
**[Profiles](🔗)** – Data about a site visitor or customer aggregate of track events in a scope. You can view profile data in Optimizely Visitor Intelligence or with the Profile Store API.
**[Segments](🔗)** – A collection of profiles that match a conditions (using filter or query), such as visitors that previously responded to a campaign.
**[Scope](🔗)** – Scope is a way of grouping Profile Store data to separate user interaction tracking based on for example brands or markets.
You can use `
HttpClient` or a third-party REST client combined with a JSON library, to make calls to the Profile Store API.
Use the Authorization header for authentication with a value in the following format: `
epi-single key;` it contains the subscription key that is passed to the API with each request.