# Get Started Learn what FusionAuth is and how to get started using it. > For the index of this section of the site, see [llms.txt](https://4002.18-224-161-104.sslip.io/docs/llms.txt) FusionAuth is a modern platform for Customer Identity and Access Management (CIAM). FusionAuth provides APIs and a responsive web user interface to support login, registration, localized email, multi-factor authentication, reporting and much more. If you're looking for employee login or a replacement for Active Directory - you may be in the wrong place. While FusionAuth can be used for nearly any application, we do not offer native desktop integration and replacing Active Directory is not on our roadmap. However, if you're looking for a solution to manage end users that can perform at scale, then keep reading. For a quick interactive introduction to FusionAuth, check out our [Get Started](https://4002.18-224-161-104.sslip.io/docs/get-started/start-here/step-1.md) guide. Here's a typical application login flow before FusionAuth: ```mermaid sequenceDiagram participant User participant App as Application User ->> App : View Homepage User ->> App : Click Login Link App ->> User : Show Login Form User ->> App : Fill Out and Submit Login Form App ->> App : Authenticates User App ->> User : Display User's Account or Other Info ``` Request flow during login before FusionAuth And here's the same application login flow after introducing FusionAuth: ```mermaid sequenceDiagram participant User participant App as Application participant FusionAuth User ->> App : View Homepage User ->> App : Click Login Link (to FusionAuth) User ->> FusionAuth : View Login Form FusionAuth ->> User : Show Login Form User ->> FusionAuth : Fill Out and Submit Login Form FusionAuth ->> FusionAuth : Authenticates User FusionAuth ->> User: Go to Redirect URI User ->> App: Request the Redirect URI App ->> FusionAuth : Is User Authenticated? FusionAuth ->> App : User is Authenticated App ->> User : Display User's Account or Other Info ``` Request flow during login after FusionAuth ## Core Concepts Legacy identity technologies have complex hierarchy and cryptic terminology like realms, principals, subjects and distinguished names. In order to simplify something perceived to be complex, the best approach is to go back to the basics, to the atomic elements and throw everything else away. When we built FusionAuth we took the back to basics approach. We identified two atomic elements of identify, Users and Applications. Everyone has Users, and Users need to be authenticated to Applications. For this reason FusionAuth is built upon four core elements: * Users - someone that can log into things * Applications - things that Users log into * Registrations - the connection between a User and an Application they have access to * Tenants - A way to logically isolate Applications, Users and Registrations ### Users A user is uniquely identified in any particular tenant by an email address or username. [Learn more.](https://4002.18-224-161-104.sslip.io/docs/get-started/core-concepts/types/users.md) ### Applications A FusionAuth Application represents an authenticated resource such as a web application, mobile application or any other application that requires authenticated users. A FusionAuth Application is defined by a name and a set of Roles. [Learn more.](https://4002.18-224-161-104.sslip.io/docs/get-started/core-concepts/types/applications.md) ### Registrations A User can be registered to one or more FusionAuth Applications. A User Registration can define one to many Application Roles. [Learn more.](https://4002.18-224-161-104.sslip.io/docs/get-started/core-concepts/types/registrations.md) ### Tenants Tenants are way to separate Users, Applications and Registrations into separate containers. Inside a Tenant, you can define any number of Users, Applications and Registrations. Across Tenants, you can define duplicate Applications, Users and Registrations. For example, you might have two Tenants and inside both Tenants you might have an Application named `Web Based Payroll` and a User with the email address `john@piedpiper.com`. Each of these Users might have a Registration to the `Web Based Payroll` Application. And finally, each of these Users might have different passwords and data. [Learn more.](https://4002.18-224-161-104.sslip.io/docs/get-started/core-concepts/types/tenants.md) ## Getting Started First you will need to install and configure FusionAuth before starting your integration. Here are some links to get you started: * [5-Minute Setup Guide](https://4002.18-224-161-104.sslip.io/docs/get-started/start-here/step-1.md) * [Register a User and Login](https://4002.18-224-161-104.sslip.io/docs/lifecycle/register-users/register-user-login-api.md) * [Self-service Registration](https://4002.18-224-161-104.sslip.io/docs/lifecycle/register-users/basic-registration-forms.md) * [Common Configuration](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install/setup.md) ### Install Options * [Docker](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install/docker.md) * [FastPath Install](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install/fusionauth-app.md) * [Package Installation](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install/fusionauth-app.md) * [All Options](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install.md) ### Create a User and call an API * [Register a User and Login](https://4002.18-224-161-104.sslip.io/docs/lifecycle/register-users/register-user-login-api.md) * [API Docs](https://4002.18-224-161-104.sslip.io/docs/apis.md) Related [Get Started Install with Docker Learn how to deploy and test FusionAuth using a Docker container.](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install/docker.md) [Extend Example Applications Learn about and download example application code for working with FusionAuth in many programming languages. quickstart](https://4002.18-224-161-104.sslip.io/docs/extend/examples/example-repos.md) [Get Started fusionauth-app Learn how to install the FusionAuth App bundle. install fusionauth](https://4002.18-224-161-104.sslip.io/docs/get-started/download-and-install/fusionauth-app.md) [Get Started Step 1 - Install FusionAuth Learn how to use FusionAuth by first installing it on your development machine. install fusionauth](https://4002.18-224-161-104.sslip.io/docs/get-started/start-here/step-1.md)