# Authentication

This chapter describes various ways to authenticate to Continuwuity.

## Authentication flows

Continuwuity implements the following authentication flows:

- **OAuth login** (also known as **next-gen auth**): clients redirect the user to Continuwuity's login/signup page.
- **Legacy login** (also known as the **UIAA** framework): clients logs in/signs up directly to the server via its own UI.

Different sets of clients support different flows, but most clients are moving towards next-gen auth. One can set which login mode(s) are allowed via the `compatibility_mode` variable of the `[global.oauth]` config file section.

:::important Configure your client well-known for OAuth logins

To ensure OAuth logins work, Continuwuity must know the path from which its Client-Server API is being served from:

```toml
[global.well_known]
client = "https://matrix.example.com"
```

Refer to the [delegation](./guides/delegation) documentation for more details.

:::
{/* TODO: !important Annotation block for .well-known/matrix/client requirement */}

## Authentication sources

Continuwuity can read user authentication data from the following sources:

- **Internal database** - this is the default setup for Continuwuity. It allows for registration, email, and password reset self-service. See the [**internal authentication documentation**](./authentication/internal).
- **Delegated authentication** - in this mode, the server connects to an OpenID Connect identity provider for user authentication. See the [**delegated authentication documentation**](./authentication/oidc).