diff --git a/CHANGELOG.md b/CHANGELOG.md
index c97de4b7..637b8c94 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,7 +13,7 @@ TODO: https://github.com/JohnXLivingston/peertube-plugin-livechat/issues/48
 
 * For anonymous users: new "log in using an external account" dialog, with following options:
   * remote Peertube account,
-  * #128: possibility to configure an OpenID Connect provider on the instance level.
+  * #128 (**Experimental Feature**): possibility to configure an OpenID Connect provider on the instance level.
 * #143: User colors: implementing [XEP-0392](https://xmpp.org/extensions/xep-0392.html) to have random colors on users nicknames
 * #330: Chat does no more use an iframe to display the chat besides the videos.
 * #330: Fullscreen chat: now uses a custom page (in other words: when opening the chat in a new tab, you will have the Peertube menu).
diff --git a/conversejs/builtin.ts b/conversejs/builtin.ts
index feeeb965..a7fd05dd 100644
--- a/conversejs/builtin.ts
+++ b/conversejs/builtin.ts
@@ -160,6 +160,7 @@ async function initConverse (
   // no viewer mode if authenticated.
   params.livechat_enable_viewer_mode = autoViewerMode && !isAuthenticated && !isRemoteWithNicknameSet
   params.livechat_external_auth_oidc_button_label = initConverseParams.externalAuthOIDC?.buttonLabel
+  params.livechat_external_auth_oidc_url = initConverseParams.externalAuthOIDC?.url
 
   if (chatIncludeMode === 'peertube-video') {
     params.livechat_mini_muc_head = true // we must replace the muc-head by the custom buttons toolbar.
diff --git a/conversejs/custom/templates/livechat-external-login-modal.js b/conversejs/custom/templates/livechat-external-login-modal.js
index b5a158c3..a2f935c3 100644
--- a/conversejs/custom/templates/livechat-external-login-modal.js
+++ b/conversejs/custom/templates/livechat-external-login-modal.js
@@ -9,14 +9,15 @@ export const tplExternalLoginModal = (el, o) => {
   const i18nRemotePeertubeUrl = __(LOC_login_remote_peertube_url)
   const i18nRemotePeertubeOpen = __('OK')
   const externalAuthOIDCButtonLabel = api.settings.get('livechat_external_auth_oidc_button_label')
+  const externalAuthOIDCUrl = api.settings.get('livechat_external_auth_oidc_url')
   return html`<div class="modal-body livechat-external-login-modal">
-    ${!externalAuthOIDCButtonLabel
+    ${!externalAuthOIDCButtonLabel || !externalAuthOIDCUrl
       ? ''
       : html`
         <div class="livechat-external-login-modal-external-auth-oidc">
           <button
             class="btn btn-primary"
-            @click=${() => console.log('ok, go')}
+            @click=${() => window.open(externalAuthOIDCUrl)}
           >
             ${externalAuthOIDCButtonLabel}
           </button>
diff --git a/conversejs/lib/plugins/livechat-specific.ts b/conversejs/lib/plugins/livechat-specific.ts
index 8844b38e..5ff95bbb 100644
--- a/conversejs/lib/plugins/livechat-specific.ts
+++ b/conversejs/lib/plugins/livechat-specific.ts
@@ -37,7 +37,7 @@ export const livechatSpecificsPlugin = {
       for (const k of [
         'hide_muc_participants',
         'livechat_enable_viewer_mode',
-        'livechat_external_auth_oidc_button_label',
+        'livechat_external_auth_oidc_button_label', 'livechat_external_auth_oidc_url',
         'livechat_mini_muc_head'
       ]) {
         _converse.api.settings.set(k, params[k])
diff --git a/conversejs/lib/plugins/livechat-viewer-mode.ts b/conversejs/lib/plugins/livechat-viewer-mode.ts
index 1157a2b4..5d89977b 100644
--- a/conversejs/lib/plugins/livechat-viewer-mode.ts
+++ b/conversejs/lib/plugins/livechat-viewer-mode.ts
@@ -9,7 +9,8 @@ export const livechatViewerModePlugin = {
       livechat_enable_viewer_mode: false,
       livechat_peertube_video_original_url: undefined,
       livechat_peertube_video_uuid: undefined,
-      livechat_external_auth_oidc_button_label: undefined
+      livechat_external_auth_oidc_button_label: undefined,
+      livechat_external_auth_oidc_url: undefined
     })
 
     const originalGetDefaultMUCNickname = _converse.getDefaultMUCNickname
diff --git a/languages/en.yml b/languages/en.yml
index 59989015..a13ef52a 100644
--- a/languages/en.yml
+++ b/languages/en.yml
@@ -83,6 +83,9 @@ external_auth_custom_oidc_button_label_description: "This label will be displaye
 external_auth_custom_oidc_discovery_url_label: "Discovery URL"
 external_auth_custom_oidc_client_id_label: "Client ID"
 external_auth_custom_oidc_client_secret_label: "Client secret"
+external_auth_custom_oidc_redirect_uris_info_description: |
+  <strong>Callback/Redirect URI:</strong>
+  If you want to configure authorized redirection URI on the external Application, please add this url:
 
 chat_behaviour_description: "<h3>Chat behaviour</h3>"
 
diff --git a/server/lib/conversejs/params.ts b/server/lib/conversejs/params.ts
index 40702df3..71242bc6 100644
--- a/server/lib/conversejs/params.ts
+++ b/server/lib/conversejs/params.ts
@@ -77,13 +77,24 @@ async function getConverseJSParams (
     roomJID
   } = connectionInfos
 
-  const oidc = ExternalAuthOIDC.singleton()
-  // TODO:
-  const externalAuthOIDC = await oidc.isOk()
-    ? {
-        buttonLabel: oidc.getButtonLabel() ?? '???'
+  let externalAuthOIDC
+  if (userIsConnected !== true) {
+    try {
+      const oidc = ExternalAuthOIDC.singleton()
+      if (await oidc.isOk()) {
+        const authUrl = oidc.getAuthUrl()
+        const buttonLabel = oidc.getButtonLabel()
+        if (authUrl && buttonLabel) {
+          externalAuthOIDC = {
+            buttonLabel: buttonLabel,
+            url: authUrl
+          }
+        }
       }
-    : undefined
+    } catch (err) {
+      options.peertubeHelpers.logger.error(err)
+    }
+  }
 
   return {
     peertubeVideoOriginalUrl: roomInfos.video?.url,
diff --git a/server/lib/diagnostic/external-auth-custom-oidc.ts b/server/lib/diagnostic/external-auth-custom-oidc.ts
index 495120ed..e901c50a 100644
--- a/server/lib/diagnostic/external-auth-custom-oidc.ts
+++ b/server/lib/diagnostic/external-auth-custom-oidc.ts
@@ -41,9 +41,9 @@ export async function diagExternalAuthCustomOIDC (test: string, _options: Regist
   }
 
   const oidc = ExternalAuthOIDC.singleton()
-  const issuer = await oidc.loadIssuer()
-  if (issuer) {
-    result.messages.push('Discovery URL loaded: ' + JSON.stringify(issuer.metadata))
+  const oidcClient = await oidc.load()
+  if (oidcClient) {
+    result.messages.push('Discovery URL loaded: ' + JSON.stringify(oidcClient.issuer.metadata))
   } else {
     result.messages.push({
       level: 'error',
diff --git a/server/lib/external-auth/oidc.ts b/server/lib/external-auth/oidc.ts
index e394ff79..52b8692b 100644
--- a/server/lib/external-auth/oidc.ts
+++ b/server/lib/external-auth/oidc.ts
@@ -1,6 +1,8 @@
 import type { RegisterServerOptions } from '@peertube/peertube-types'
 import { URL } from 'url'
-import { Issuer } from 'openid-client'
+import { Issuer, BaseClient } from 'openid-client'
+import { getBaseRouterRoute } from '../helpers'
+import { canonicalizePluginUri } from '../uri/canonicalize'
 
 let singleton: ExternalAuthOIDC | undefined
 
@@ -13,8 +15,14 @@ class ExternalAuthOIDC {
   private readonly discoveryUrl: string | undefined
   private readonly clientId: string | undefined
   private readonly clientSecret: string | undefined
+  private readonly redirectUri: string
+
   private ok: boolean | undefined
+
   private issuer: Issuer | undefined | null
+  private client: BaseClient | undefined | null
+  private authorizationUrl: string | null
+
   protected readonly logger: {
     debug: (s: string) => void
     info: (s: string) => void
@@ -28,7 +36,8 @@ class ExternalAuthOIDC {
     buttonLabel: string | undefined,
     discoveryUrl: string | undefined,
     clientId: string | undefined,
-    clientSecret: string | undefined
+    clientSecret: string | undefined,
+    redirectUri: string
   ) {
     this.logger = {
       debug: (s) => logger.debug('[ExternalAuthOIDC] ' + s),
@@ -38,6 +47,8 @@ class ExternalAuthOIDC {
     }
 
     this.enabled = !!enabled
+    this.redirectUri = redirectUri
+    this.authorizationUrl = null
     if (this.enabled) {
       this.buttonLabel = buttonLabel
       this.discoveryUrl = discoveryUrl
@@ -55,6 +66,16 @@ class ExternalAuthOIDC {
     return !this.enabled
   }
 
+  /**
+   * Get the url to open for external authentication.
+   * Note: If the singleton is not loaded yet, returns null.
+   *   This means that the feature will only be available when the load as complete.
+   * @returns the url to open
+   */
+  getAuthUrl (): string | null {
+    return this.authorizationUrl ?? null
+  }
+
   /**
    * Get the button
    * @returns Button label
@@ -122,14 +143,21 @@ class ExternalAuthOIDC {
   }
 
   /**
-   * Ensure the issuer is loaded.
+   * Ensure the issuer is loaded, and the client instanciated.
    * @returns the issuer if enabled
    */
-  async loadIssuer (): Promise<Issuer | null> {
-    // this.issuer === null means we already tried, but it failed.
-    if (this.issuer !== undefined) { return this.issuer }
+  async load (): Promise<BaseClient | null> {
+    // this.client === null means we already tried, but it failed.
+    if (this.client !== undefined) { return this.client }
 
-    if (!await this.isOk()) { return null }
+    // First, reset the authentication url:
+    this.authorizationUrl = null
+
+    if (!await this.isOk()) {
+      this.issuer = null
+      this.client = null
+      return null
+    }
 
     try {
       this.issuer = await Issuer.discover(this.discoveryUrl as string)
@@ -137,8 +165,38 @@ class ExternalAuthOIDC {
     } catch (err) {
       this.logger.error(err as string)
       this.issuer = null
+      this.client = null
     }
-    return this.issuer
+
+    if (!this.issuer) {
+      this.client = null
+      return null
+    }
+
+    try {
+      this.client = new this.issuer.Client({
+        client_id: this.clientId as string,
+        client_secret: this.clientSecret as string,
+        redirect_uris: [this.redirectUri],
+        response_types: ['code']
+      })
+    } catch (err) {
+      this.logger.error(err as string)
+      this.client = null
+    }
+
+    if (!this.client) {
+      return null
+    }
+
+    try {
+      this.authorizationUrl = this.client.authorizationUrl()
+    } catch (err) {
+      this.logger.error(err as string)
+      this.authorizationUrl = null
+    }
+
+    return this.client
   }
 
   /**
@@ -167,7 +225,8 @@ class ExternalAuthOIDC {
       settings['external-auth-custom-oidc-button-label'] as string | undefined,
       settings['external-auth-custom-oidc-discovery-url'] as string | undefined,
       settings['external-auth-custom-oidc-client-id'] as string | undefined,
-      settings['external-auth-custom-oidc-client-secret'] as string | undefined
+      settings['external-auth-custom-oidc-client-secret'] as string | undefined,
+      ExternalAuthOIDC.redirectUri(options)
     )
 
     return singleton
@@ -183,6 +242,13 @@ class ExternalAuthOIDC {
     }
     return singleton
   }
+
+  public static redirectUri (options: RegisterServerOptions): string {
+    const path = getBaseRouterRoute(options) + 'oidc/cb'
+    return canonicalizePluginUri(options, path, {
+      removePluginVersion: true
+    })
+  }
 }
 
 export {
diff --git a/server/lib/settings.ts b/server/lib/settings.ts
index 99c72c8d..63912745 100644
--- a/server/lib/settings.ts
+++ b/server/lib/settings.ts
@@ -5,11 +5,13 @@ import { RoomChannel } from './room-channel'
 import { BotsCtl } from './bots/ctl'
 import { ExternalAuthOIDC } from './external-auth/oidc'
 import { loc } from './loc'
+const escapeHTML = require('escape-html')
 
 type AvatarSet = 'sepia' | 'cat' | 'bird' | 'fenec' | 'abstract' | 'legacy'
 
 async function initSettings (options: RegisterServerOptions): Promise<void> {
   const { peertubeHelpers, settingsManager } = options
+  const logger = peertubeHelpers.logger
 
   initImportantNotesSettings(options)
   initChatSettings(options)
@@ -21,6 +23,30 @@ async function initSettings (options: RegisterServerOptions): Promise<void> {
   initChatServerAdvancedSettings(options)
 
   await ExternalAuthOIDC.initSingleton(options)
+  const loadOidc = (): void => {
+    try {
+      const oidc = ExternalAuthOIDC.singleton()
+      oidc.isOk().then(
+        () => {
+          logger.info('Loading External Auth OIDC...')
+          oidc.load().then(
+            () => {
+              logger.info('External Auth OIDC loaded')
+            },
+            () => {
+              logger.error('Loading the External Auth OIDC failed')
+            }
+          )
+        },
+        () => {
+          logger.info('No valid External Auth OIDC, nothing loaded')
+        }
+      )
+    } catch (err) {
+      logger.error(err as string)
+    }
+  }
+  loadOidc() // we don't have to wait (can take time, it will do external http requests)
 
   let currentProsodyRoomtype = (await settingsManager.getSettings(['prosody-room-type']))['prosody-room-type']
 
@@ -30,6 +56,7 @@ async function initSettings (options: RegisterServerOptions): Promise<void> {
     // To avoid race condition, we will just stop and start the bots at every settings saving.
     await BotsCtl.destroySingleton()
     await BotsCtl.initSingleton(options)
+    loadOidc() // we don't have to wait (can take time, it will do external http requests)
 
     await ExternalAuthOIDC.initSingleton(options)
 
@@ -145,12 +172,21 @@ function initFederationSettings ({ registerSetting }: RegisterServerOptions): vo
  * Registers settings related to the "External Authentication" section.
  * @param param0 server options
  */
-function initExternalAuth ({ registerSetting }: RegisterServerOptions): void {
+function initExternalAuth (options: RegisterServerOptions): void {
+  const registerSetting = options.registerSetting
+
   registerSetting({
     type: 'html',
     private: true,
     descriptionHTML: loc('external_auth_description')
   })
+
+  registerSetting({
+    type: 'html',
+    private: true,
+    descriptionHTML: loc('experimental_warning')
+  })
+
   registerSetting({
     name: 'external-auth-custom-oidc',
     label: loc('external_auth_custom_oidc_label'),
@@ -159,6 +195,20 @@ function initExternalAuth ({ registerSetting }: RegisterServerOptions): void {
     default: false,
     private: true
   })
+
+  registerSetting({
+    type: 'html',
+    name: 'external-auth-custom-oidc-redirect-uris-info',
+    private: true,
+    descriptionHTML: loc('external_auth_custom_oidc_redirect_uris_info_description')
+  })
+  registerSetting({
+    type: 'html',
+    name: 'external-auth-custom-oidc-redirect-uris',
+    private: true,
+    descriptionHTML: `<ul><li>${escapeHTML(ExternalAuthOIDC.redirectUri(options)) as string}</li></ul>`
+  })
+
   registerSetting({
     name: 'external-auth-custom-oidc-button-label',
     label: loc('external_auth_custom_oidc_button_label_label'),
diff --git a/shared/lib/types.ts b/shared/lib/types.ts
index cf9473e3..6a109dbb 100644
--- a/shared/lib/types.ts
+++ b/shared/lib/types.ts
@@ -24,6 +24,7 @@ interface InitConverseJSParams {
   autofocus?: boolean
   externalAuthOIDC?: {
     buttonLabel: string
+    url: string
   }
 }