feat: Add docs for third party OIDC providers

docs/authentication/enterprise-connections/oidc/custom-provider.mdx

@@ -0,0 +1,61 @@
+---
+title: Add a custom OIDC Provider as an Enterprise Connection
+description: Learn how to integrate a custom OIDC provider with Clerk for Enterprise SSO.
+---
+<TutorialHero
+  beforeYouStart={[
+    {
+      title: "Add the Enhanced Authentication add-on to your Pro plan",
+      link: "/pricing",
+      icon: "plus-circle",
+    },
+    {
+      title: "Enable email address as an identifier for your app",
+      link: "/docs/authentication/configuration/sign-up-sign-in-options#identifiers",
+      icon: "key",
+    },
+  ]}
+>
+  - Use a third-party OIDC provider to authenticate users with Enterprise SSO
+</TutorialHero>
+<Steps>
+  ### Set up an Enterprise Connection in Clerk
+
+  To create an Enterprise connection in Clerk:
+
+  1. In the Clerk Dashboard, navigate to the [**SSO Connections**](https://dashboard.clerk.com/last-active?path=user-authentication/sso-connections) page.
+  1. Select **Add connection** and select **For specific domains**.
+  1. Under **Third party**, select **OIDC**.
+  1. Add the **Name** of the connection. 
+  1. Add the **Key** of the provider. This is the provider's unique identifier (cannot be changed after creation).
+  1. Add the **Specific Domain** that you want to allow this connection for. This is the domain of the users you want to allow to sign in to your application.
+  1. Select **Add connection**. You will be redirected to the connection's configuration page.
+
+  The next steps involve configuring both your Identity Provider (IdP) and Clerk. Keep both dashboards open as you'll need to reference them.
+
+  ### Configure your Identity Provider
+
+  If needed, create a new application in your IdP. Then, copy the **Authorized redirect URLs** from the connection's configuration page and add them to your IdP's whitelisted URLs.
+
+  ### Configure the connection
+
+  Locate your application's Client ID, Client Secret, and discovery endpoint in your IdP's settings. Copy these values to the **Identity Provider Configuration** section on the connection's configuration page.
+
+  Finally set up the minimum required scopes according to the provider's documentation. The most commonly used OIDC scopes are `openid`, `email`, and `profile`.
+
+  ### Attribute mapping (optional)
+
+  If your provider returns claims in a non-standard format, under **Attribute mapping**, configure the mapping to match your provider's claim format.
+
+  > [!CAUTION]
+  > OIDC Enterprise connections require the `email_verified` claim to verify email ownership.  For providers that don't return this claim, you can set a default value of true - but ensure you fully trust the Identity Provider before doing so to prevent exploits like [nOAuth](https://www.descope.com/blog/post/noauth).
+
+  ### Enable the connection for Clerk
+
+  To make the connection available for your users to authenticate with:
+
+  1. In the Clerk Dashboard, you should still have the connection's configuration page open. If not, navigate to the [**SSO Connections**](https://dashboard.clerk.com/last-active?path=user-authentication/sso-connections) page and select the connection.
+  1. Toggle on **Enable connection** and select **Save**.
+</Steps>
+
+

docs/authentication/enterprise-connections/overview.mdx

@@ -24,7 +24,11 @@ To configure subdomains for a SAML connection:
 > [!NOTE]
 > To enable the **Allow subdomains** option, your SAML connection domain must be an [eTLD+1](https://developer.mozilla.org/en-US/docs/Glossary/eTLD).
 
-## EASIE
+## OIDC
+
+Clerk also supports Enterprise SSO via the OpenID Connect (OIDC) protocol, either through [EASIE](#easie) or by [integrating with any OIDC-compatible provider](/docs/authentication/enterprise-connections/oidc/custom-provider).
+
+### EASIE
 
 [EASIE](https://easie.dev) SSO is a way for applications to provide enterprise-grade SSO through a multi-tenant OpenID provider. It is designed to be an easier alternative to SAML SSO.
 
@@ -33,15 +37,15 @@ The following IdPs are supported: Google Workspace and Microsoft Entra ID. For _
 - [Google](docs/authentication/social-connections/google)
 - [Microsoft](docs/authentication/social-connections/azure)
 
-### Automatic deprovisioning
+#### Automatic deprovisioning
 
 Clerk prevents users linked to deprovisioned accounts in the OpenID provider from accessing the app.
 
 Within 10 minutes of a user being removed from the OpenID provider (e.g. [suspendeded](https://support.google.com/a/answer/33312?hl=en) or [deleted](https://support.google.com/a/answer/33314?hl=en) via Google Workspace, or [deleted](https://learn.microsoft.com/en-us/entra/fundamentals/how-to-create-delete-users#delete-a-user) via Microsoft Entra), Clerk will recognize that the user has been deprovisioned and will revoke that user's existing sessions.
 
 It is ultimately the app's responsibility to handle this unauthenticated state and display something appropriate to the user. For example, Next.js apps using [`auth.protect()`](docs/references/nextjs/auth#auth-protect) will automatically redirect the user to the sign-in page.
 
-## SAML vs. EASIE
+### SAML vs. EASIE
 
 The primary security difference between EASIE SSO and SAML SSO is that EASIE depends on a multi-tenant identity provider, while SAML depends on a single-tenant identity provider. Relying on a multi-tenant provider **increases** the risk that a user from one tenant will mistakenly be granted access to the resources of another tenant. While Clerk implements [measures to address this risk](https://easie.dev/#mitigating-tenant-crossover-vulnerabilities), apps that require single-tenant IdPs should opt for SAML.
 

docs/manifest.json

@@ -579,6 +579,17 @@
                               }
                             ]
                           ]
+                        },
+                        {
+                          "title": "OIDC",
+                          "items": [
+                            [
+                              {
+                                "title": "Custom provider",
+                                "href": "/docs/authentication/enterprise-connections/oidc/custom-provider"
+                              }
+                            ]
+                          ]
                         }
                       ]
                     ]