diff --git a/frontend/auth/App.vue b/frontend/auth/App.vue
index 3933b54..73f50f0 100644
--- a/frontend/auth/App.vue
+++ b/frontend/auth/App.vue
@@ -37,11 +37,13 @@ function normalizeHost(raw) {
 }
 
 /**
- * Host mode is active when an auth_host is configured AND the current host differs from it.
+ * Host mode is active when an own_auth_host is configured AND the current host differs from it.
  * In host mode, we show a limited profile view with logout and link to full profile.
+ * own_auth_host (not auth_host) is used so that realms sharing another realm's auth host
+ * still serve the full profile on their own hosts.
  */
 const isHostMode = computed(() => {
-  const authHost = store.settings?.auth_host
+  const authHost = store.settings?.own_auth_host
   if (!authHost) return false
   const currentHost = normalizeHost(window.location.host)
   const configuredHost = normalizeHost(authHost)
@@ -99,7 +101,7 @@ onMounted(async () => {
   if (rpName) {
     // In host mode, show "account summary" style title
     // Settings are loaded but isHostMode depends on them, so check here
-    const authHost = store.settings?.auth_host
+    const authHost = store.settings?.own_auth_host
     const inHostMode = authHost && normalizeHost(window.location.host) !== normalizeHost(authHost)
     document.title = inHostMode ? `${rpName} · Account summary` : rpName
   }
diff --git a/frontend/auth/admin/AdminApp.vue b/frontend/auth/admin/AdminApp.vue
index 8b1949a..f0fc8f0 100644
--- a/frontend/auth/admin/AdminApp.vue
+++ b/frontend/auth/admin/AdminApp.vue
@@ -28,6 +28,7 @@ const error = ref(null)
 const orgs = ref([])
 const permissions = ref([])
 const oidcClients = ref([])
+const realms = ref([])
 const currentOrgId = ref(null) // UUID of selected org for detail view
 const currentUserId = ref(null) // UUID for user detail view
 const currentOidcId = ref(null) // UUID for OIDC client detail view
@@ -174,6 +175,16 @@ async function loadAdminData() {
   oidcClients.value = Object.entries(data.oidc_clients).map(([uuid, c]) => ({ uuid, ...c }))
 }
 
+// Realm list is master-admin only; callers guard on isMasterAdmin
+async function loadRealms() {
+  try {
+    realms.value = await apiJson('/auth/api/admin/realms/')
+  } catch (e) {
+    console.warn('Unable to load realms', e)
+    realms.value = []
+  }
+}
+
 // Helper to get users for a role as sorted array of [uuid, user]
 function roleUsers(org, roleUuid) {
   return Object.entries(org.users)
@@ -207,6 +218,7 @@ function clearSensitiveState() {
   orgs.value = []
   permissions.value = []
   oidcClients.value = []
+  realms.value = []
   userDetail.value = null
   editingOidcClient.value = null
   authenticated.value = false
@@ -236,6 +248,7 @@ async function load() {
     await loadAdminData()
     // If we get here, user has admin access - now fetch user info for display
     await loadUserInfo()
+    if (isMasterAdmin.value) await loadRealms()
 
     if (!isMasterAdmin.value && isOrgAdmin.value && orgs.value.length === 1) {
       if (!window.location.hash || window.location.hash === '#overview') {
@@ -462,21 +475,41 @@ function createPermissionForClient(clientId) {
   openDialog('perm-create', { display_name: '', scope: '', domain: clientId })
 }
 
-async function openServerConfig() {
-  try {
-    const config = await apiJson('/auth/api/admin/server-config')
-    // Strip https:// scheme from stored origins and auth_host for editing
-    const origins = (config.origins || []).map(o => o.replace(/^https:\/\//, ''))
-    const auth_host = (config.auth_host || '').replace(/^https:\/\//, '')
-    openDialog('server-config', {
-      rp_name: config.rp_name || '',
-      auth_host,
-      origins,
-      originValidation: origins.map(() => null),
-    })
-  } catch (e) {
-    authStore.showMessage(e.message || 'Failed to load server configuration', 'error')
-  }
+function createRealm() {
+  openDialog('realm-edit', {
+    isNew: true,
+    rp_id: '',
+    rp_name: '',
+    auth_host: '',
+    origins: [],
+    originValidation: [],
+    authHostValidation: null,
+  })
+}
+
+function openRealm(realm) {
+  // Strip https:// scheme from stored origins and auth_host for editing
+  const origins = (realm.origins || []).map(o => o.replace(/^https:\/\//, ''))
+  openDialog('realm-edit', {
+    isNew: false,
+    rp_id: realm.rp_id,
+    rp_name: realm.rp_name || '',
+    auth_host: (realm.auth_host || '').replace(/^https:\/\//, ''),
+    origins,
+    originValidation: origins.map(() => null),
+    authHostValidation: null,
+  })
+}
+
+function deleteRealm(realm) {
+  openDialog('confirm', {
+    message: `Delete realm "${realm.rp_id}"? This is refused while any passkeys remain registered for it.`,
+    action: async () => {
+      await apiJson(`/auth/api/admin/realms/${realm.rp_id}`, { method: 'DELETE' })
+      authStore.showMessage(`Realm "${realm.rp_id}" deleted.`, 'success', 2500)
+      await loadRealms()
+    }
+  })
 }
 
 function deleteOidcClient(client) {
@@ -900,25 +933,32 @@ async function submitDialog() {
           authStore.showMessage(e.message || `Failed to ${isNew ? 'create' : 'update'} OIDC client`, 'error')
         })
       return // Don't call closeDialog() again
-    } else if (t === 'server-config') {
-      const rp_name = dialog.value.data.rp_name?.trim() || ''
-      const auth_host = dialog.value.data.auth_host?.trim() || ''
+    } else if (t === 'realm-edit') {
+      const d = dialog.value.data
+      const rp_id = d.rp_id?.trim().toLowerCase()
+      if (!rp_id) throw new Error('RP ID (domain) required')
+      const rp_name = d.rp_name?.trim() || ''
+      const auth_host = d.auth_host?.trim() || ''
       // Origins are stored as-is (hostnames); backend normalizes with https://
-      const origins = dialog.value.data.origins
+      const origins = (d.origins || [])
         .map(o => o.trim())
         .filter(o => o)
 
       closeDialog()
-      apiJson('/auth/api/admin/server-config', { method: 'PATCH', body: { rp_name, auth_host, origins } })
+      const req = d.isNew
+        ? apiJson('/auth/api/admin/realms/', { method: 'POST', body: { rp_id, rp_name, auth_host, origins } })
+        : apiJson(`/auth/api/admin/realms/${rp_id}`, { method: 'PATCH', body: { rp_name, auth_host, origins } })
+      req
         .then(() => {
-          authStore.showMessage('Server configuration updated.', 'success', 2500)
+          authStore.showMessage(`Realm "${rp_id}" ${d.isNew ? 'created' : 'updated'}.`, 'success', 2500)
+          loadRealms()
           // Reload settings to reflect rp_name changes
-          authStore.loadSettings().then(() => {
+          authStore.loadSettings(true).then(() => {
             if (authStore.settings?.rp_name) document.title = authStore.settings.rp_name + ' Admin'
           })
         })
         .catch(e => {
-          authStore.showMessage(e.message || 'Failed to update server configuration', 'error')
+          authStore.showMessage(e.message || 'Failed to save realm', 'error')
         })
       return // Don't call closeDialog() again
     } else if (t === 'confirm') {
@@ -973,6 +1013,7 @@ async function submitDialog() {
                   :orgs="orgs"
                   :permissions="permissions"
                   :oidc-clients="oidcClients"
+                  :realms="realms"
                   :navigation-disabled="hasActiveModal"
                   :permission-summary="permissionSummary"
                   @create-org="createOrg"
@@ -986,7 +1027,9 @@ async function submitDialog() {
                   @create-oidc-client="createOidcClient"
                   @open-oidc-client="openOidcClient"
                   @delete-oidc-client="deleteOidcClient"
-                  @open-server-config="openServerConfig"
+                  @create-realm="createRealm"
+                  @open-realm="openRealm"
+                  @delete-realm="deleteRealm"
                   @navigate-out="handlePanelNavigateOut"
                 />
 
@@ -1047,7 +1090,6 @@ async function submitDialog() {
     <AdminDialogs
       :dialog="dialog"
       :permission-id-pattern="PERMISSION_ID_PATTERN"
-      :settings="authStore.settings"
       @submit-dialog="submitDialog"
       @close-dialog="closeDialog"
       @reset-oidc-secret="resetOidcSecret"
diff --git a/frontend/src/admin/AdminDialogs.vue b/frontend/src/admin/AdminDialogs.vue
index fa588c1..b3658bb 100644
--- a/frontend/src/admin/AdminDialogs.vue
+++ b/frontend/src/admin/AdminDialogs.vue
@@ -6,32 +6,59 @@ import { useAuthStore } from '@/stores/auth'
 
 const props = defineProps({
   dialog: Object,
-  PERMISSION_ID_PATTERN: String,
-  settings: Object
+  PERMISSION_ID_PATTERN: String
 })
 
 const emit = defineEmits(['submitDialog', 'closeDialog', 'resetOidcSecret', 'createPermissionForClient'])
 
 const NAME_EDIT_TYPES = new Set(['org-update', 'role-update', 'user-update-name'])
 const NO_SUBMIT_TYPES = new Set([])
-const rpId = computed(() => props.settings?.rp_id || 'the configured domain')
 const discoveryUrl = computed(() => `${window.location.origin}/.well-known/openid-configuration`)
 
+// The rp-id of the realm being edited in the 'realm-edit' dialog
+const realmRpId = computed(() => props.dialog?.data?.rp_id || '')
+
 // Initialize validation properties
-if (props.dialog?.data && props.dialog.type === 'server-config') {
+if (props.dialog?.data && props.dialog.type === 'realm-edit') {
   if (!('authHostValidation' in props.dialog.data)) {
     props.dialog.data.authHostValidation = null
   }
+  if (!('originValidation' in props.dialog.data)) {
+    props.dialog.data.originValidation = (props.dialog.data.origins || []).map(() => null)
+  }
 }
 
+// Block submit on hard errors: malformed entries, auth-host outside the
+// rp-id domain, or validation still in flight. Connectivity and rp-id
+// mismatch results are warnings only (e.g. related origins hosted elsewhere,
+// or a new realm whose DNS is not routed to this instance yet).
 const isValidationInvalid = computed(() => {
-  if (props.dialog?.type !== 'server-config') return false
+  if (props.dialog?.type !== 'realm-edit') return false
   const d = props.dialog.data
-  if (d.authHostValidation?.startsWith('invalid') || d.authHostValidation === 'validating') return true
+  if (d.authHostValidation === 'invalid-domain' || d.authHostValidation === 'validating') return true
   if (d.originValidation?.some(v => v === 'invalid' || v === 'validating')) return true
+  if (props.dialog.type === 'realm-edit' && d.isNew && !isWellFormedDomain(d.rp_id || '')) return true
   return false
 })
 
+// Well-known URL that must list any related (non-subdomain) origins.
+// Browsers always fetch it from the rp-id domain, never the auth host.
+const wellKnownUrl = computed(() => {
+  const host = (props.dialog?.data?.rp_id || '').replace(/^https:\/\//, '').replace(/\/+$/, '')
+  return host ? `https://${host}/.well-known/webauthn` : ''
+})
+
+// Number of related (non-subdomain) origins in the realm dialog
+const relatedOriginCount = computed(() => {
+  const d = props.dialog?.data
+  if (!d?.origins) return 0
+  const id = realmRpId.value
+  return d.origins.filter(o => {
+    const h = originHostname(o)
+    return h && id && h !== id && !h.endsWith('.' + id)
+  }).length
+})
+
 // Copy-to-clipboard helper
 const authStore = useAuthStore()
 function copyText(value, label) {
@@ -43,7 +70,7 @@ function copyText(value, label) {
 function addOrigin() {
   const d = props.dialog?.data
   if (d) {
-    d.origins.push(rpId.value)
+    d.origins.push(realmRpId.value)
     d.originValidation.push(null)
     validateOrigin(d.origins[d.origins.length - 1], d.origins.length - 1)
   }
@@ -67,17 +94,32 @@ function focusOriginStart(e) {
   e.target.setSelectionRange(0, 0)
 }
 
-function validateOriginDomain(origin, rpId) {
-  if (!origin.trim()) return false
+function isWellFormedDomain(value) {
+  if (!value.trim()) return false
   try {
-    const url = origin.startsWith('http') ? new URL(origin) : new URL('https://' + origin)
-    const hostname = url.hostname
-    return hostname === rpId || hostname.endsWith('.' + rpId)
+    const url = value.startsWith('http') ? new URL(value) : new URL('https://' + value)
+    return url.hostname.includes('.') || url.hostname === 'localhost'
   } catch {
     return false
   }
 }
 
+function originHostname(origin) {
+  if (!origin.trim()) return null
+  try {
+    const url = origin.startsWith('http') ? new URL(origin) : new URL('https://' + origin)
+    return url.hostname || null
+  } catch {
+    return null
+  }
+}
+
+function isWithinDomain(origin, rpId) {
+  const hostname = originHostname(origin)
+  if (!hostname) return false
+  return hostname === rpId || hostname.endsWith('.' + rpId)
+}
+
 async function validateOriginConnectivity(origin, i) {
   const d = props.dialog?.data
   if (!d) return
@@ -90,22 +132,17 @@ async function validateOriginConnectivity(origin, i) {
       method: 'GET',
       headers: { 'Accept': 'application/json' }
     })
+    if (d.origins[i] !== origin) return // origin changed while validating
     if (response.ok) {
       const data = await response.json()
-      // Check if it returns valid settings (has rp_id and matches current rp_id)
-      const result = (data.rp_id && data.rp_id === rpId.value) ? 'valid' : 'invalid'
-      // Only update if the origin hasn't changed
-      if (d.origins[i] === origin) {
-        d.originValidation[i] = result
-      }
+      // Valid when the origin is served by this instance for the edited realm
+      d.originValidation[i] = (data.rp_id && data.rp_id === realmRpId.value) ? 'valid' : 'mismatch'
     } else {
-      if (d.origins[i] === origin) {
-        d.originValidation[i] = 'invalid'
-      }
+      d.originValidation[i] = 'unreachable'
     }
   } catch (e) {
     if (d.origins[i] === origin) {
-      d.originValidation[i] = 'invalid'
+      d.originValidation[i] = 'unreachable'
     }
   }
 }
@@ -114,8 +151,9 @@ function validateOrigin(origin, i) {
   const d = props.dialog?.data
   if (!d) return
 
-  const id = rpId.value
-  if (validateOriginDomain(origin, id)) {
+  // Related origins on unrelated domains are allowed (WebAuthn ROR), so any
+  // well-formed origin passes; connectivity is checked as a hint only.
+  if (originHostname(origin)) {
     validateOriginConnectivity(origin, i)
   } else {
     d.originValidation[i] = 'invalid'
@@ -134,22 +172,16 @@ async function validateAuthHostConnectivity(authHost) {
       method: 'GET',
       headers: { 'Accept': 'application/json' }
     })
+    if (d.auth_host !== authHost) return // auth_host changed while validating
     if (response.ok) {
       const data = await response.json()
-      // Check if it returns valid settings (has rp_id and matches current rp_id)
-      const result = (data.rp_id && data.rp_id === rpId.value) ? 'valid' : 'invalid'
-      // Only update if the auth_host hasn't changed
-      if (d.auth_host === authHost) {
-        d.authHostValidation = result
-      }
+      d.authHostValidation = (data.rp_id && data.rp_id === realmRpId.value) ? 'valid' : 'mismatch'
     } else {
-      if (d.auth_host === authHost) {
-        d.authHostValidation = 'invalid-connectivity'
-      }
+      d.authHostValidation = 'unreachable'
     }
   } catch (e) {
     if (d.auth_host === authHost) {
-      d.authHostValidation = 'invalid-connectivity'
+      d.authHostValidation = 'unreachable'
     }
   }
 }
@@ -157,12 +189,11 @@ async function validateAuthHostConnectivity(authHost) {
 function validateAuthHost() {
   const d = props.dialog?.data
   if (!d || !d.auth_host?.trim()) {
-    d.authHostValidation = null // Allow empty
+    if (d) d.authHostValidation = null // Allow empty
     return
   }
 
-  const id = rpId.value
-  if (validateOriginDomain(d.auth_host, id)) {
+  if (isWithinDomain(d.auth_host, realmRpId.value)) {
     validateAuthHostConnectivity(d.auth_host)
   } else {
     d.authHostValidation = 'invalid-domain'
@@ -181,7 +212,7 @@ function validateAuthHost() {
         <template v-else-if="dialog.type==='user-update-name'">Edit User Name</template>
         <template v-else-if="dialog.type==='perm-create' || dialog.type==='perm-display'">{{ dialog.type === 'perm-create' ? 'Create Permission' : 'Edit Permission' }}</template>
         <template v-else-if="dialog.type==='oidc-edit'">{{ dialog.data?.isNew ? 'New OIDC Client' : 'OIDC Client' }}</template>
-        <template v-else-if="dialog.type==='server-config'">Server Options</template>
+        <template v-else-if="dialog.type==='realm-edit'">{{ dialog.data?.isNew ? 'Add Realm' : 'Edit Realm' }}</template>
         <template v-else-if="dialog.type==='confirm'">Confirm</template>
       </h3>
       <form @submit.prevent="$emit('submitDialog')" class="modal-form">
@@ -239,21 +270,28 @@ function validateAuthHost() {
           <label>Domain Scope
             <input v-model="dialog.data.domain" data-form-type="other" />
           </label>
-          <p class="small muted">A domain ({{ rpId }} or subdomain) restricts this permission to that host. An OIDC client UUID sends it as a <em>groups</em> claim to that client.</p>
+          <p class="small muted">A domain restricts this permission to that host (any configured realm's rp-id or a subdomain of it). An OIDC client UUID sends it as a <em>groups</em> claim to that client.</p>
         </template>
-        <template v-else-if="dialog.type==='server-config'">
-          <label>Site Branding (rp-name)
-            <input v-model="dialog.data.rp_name" :placeholder="rpId" />
+        <template v-else-if="dialog.type==='realm-edit'">
+          <template v-if="dialog.data.isNew">
+            <label>RP ID (domain)
+              <input v-model="dialog.data.rp_id" placeholder="example.com" data-form-type="other" required />
+            </label>
+            <p class="small muted">The domain passkeys are registered for. Cannot be changed later.</p>
+          </template>
+          <p v-else class="small muted">Realm: <strong>{{ dialog.data.rp_id }}</strong></p>
+          <label>Display Name (rp-name)
+            <input v-model="dialog.data.rp_name" :placeholder="dialog.data.rp_id" />
           </label>
           <label>Dedicated Authentication Site (auth-host)
-            <input v-model="dialog.data.auth_host" @input="validateAuthHost()" :class="{ 'input-error': dialog.data.authHostValidation?.startsWith('invalid') }" />
+            <input v-model="dialog.data.auth_host" @input="validateAuthHost()" :class="{ 'input-error': dialog.data.authHostValidation === 'invalid-domain' }" />
           </label>
           <p v-if="dialog.data.authHostValidation === 'validating'" class="small muted">Validating...</p>
           <p v-else-if="dialog.data.authHostValidation === 'valid'" class="small muted">Valid</p>
-          <p v-else-if="dialog.data.authHostValidation === 'invalid-domain'" class="small muted">Invalid domain</p>
-          <p v-else-if="dialog.data.authHostValidation === 'invalid-connectivity'" class="small muted">Well-formed but unreachable</p>
-          <p v-else-if="dialog.data.authHostValidation === 'invalid'" class="small muted">Invalid configuration</p>
-          <p v-else-if="dialog.data.authHostValidation === 'invalid'" class="small muted">Enter {{ rpId }} or any subdomain of it.</p>
+          <p v-else-if="dialog.data.authHostValidation === 'invalid-domain'" class="small muted">Must be {{ dialog.data.rp_id }} or a subdomain of it.</p>
+          <p v-else-if="dialog.data.authHostValidation === 'unreachable'" class="small muted">Well-formed but unreachable — make sure it is routed to this instance.</p>
+          <p v-else-if="dialog.data.authHostValidation === 'mismatch'" class="small muted">Reachable, but does not serve this realm.</p>
+          <p v-else class="small muted">Optional. Leave empty to serve authentication on {{ dialog.data.rp_id }} itself.</p>
           <div class="origin-label">
             Allowed Origins
             <button type="button" class="icon-btn origin-add-btn" @click="addOrigin" aria-label="Add origin" title="Add origin">➕</button>
@@ -269,9 +307,18 @@ function validateAuthHost() {
               />
               <button type="button" class="icon-btn delete-icon" @click="removeOrigin(i)" aria-label="Remove origin" title="Remove origin">❌</button>
             </div>
+            <p v-if="dialog.data.originValidation.some(v => v === 'unreachable')" class="small muted">Some origins are unreachable — make sure they are routed to this instance, or host them externally.</p>
+            <p v-else-if="dialog.data.originValidation.some(v => v === 'mismatch')" class="small muted">Some origins are reachable but do not serve this realm.</p>
           </div>
-          <p v-if="!dialog.data.origins.length" class="small muted">{{ rpId }} and all subdomains allowed.</p>
-          <p v-else class="small muted">Only the above sites are allowed to authenticate.</p>
+          <p v-if="!dialog.data.origins.length" class="small muted">{{ dialog.data.rp_id }} and all subdomains allowed.</p>
+          <p v-else class="small muted">Only the above sites are allowed to authenticate. Origins on unrelated domains count as related origins (max 5 per realm).</p>
+          <template v-if="relatedOriginCount > 0">
+            <p class="small muted">
+              Related origins require the rp-id domain to list them at
+              <a :href="wellKnownUrl" target="_blank" rel="noopener noreferrer">{{ wellKnownUrl }}</a>
+              — this instance serves it automatically; copy it there if the main site is hosted elsewhere.
+            </p>
+          </template>
         </template>
         <template v-else-if="dialog.type==='confirm'">
           <p>{{ dialog.data.message }}</p>
diff --git a/frontend/src/admin/AdminOverview.vue b/frontend/src/admin/AdminOverview.vue
index e35a68f..876cce2 100644
--- a/frontend/src/admin/AdminOverview.vue
+++ b/frontend/src/admin/AdminOverview.vue
@@ -8,11 +8,12 @@ const props = defineProps({
   orgs: Array,
   permissions: Array,
   oidcClients: Array,
+  realms: Array,
   permissionSummary: Object,
   navigationDisabled: { type: Boolean, default: false }
 })
 
-const emit = defineEmits(['createOrg', 'openOrg', 'updateOrg', 'deleteOrg', 'toggleOrgPermission', 'openDialog', 'deletePermission', 'renamePermissionDisplay', 'createOidcClient', 'openOidcClient', 'deleteOidcClient', 'openServerConfig', 'navigateOut'])
+const emit = defineEmits(['createOrg', 'openOrg', 'updateOrg', 'deleteOrg', 'toggleOrgPermission', 'openDialog', 'deletePermission', 'renamePermissionDisplay', 'createOidcClient', 'openOidcClient', 'deleteOidcClient', 'createRealm', 'openRealm', 'deleteRealm', 'navigateOut'])
 
 // Template refs for navigation
 const orgActionsRef = ref(null)
@@ -425,14 +426,50 @@ defineExpose({ focusFirstElement })
     </table>
   </div>
 
-  <div v-if="isMasterAdmin" class="server-options-section">
+  <div v-if="isMasterAdmin" class="realms-section">
     <div class="section-header">
-      <h2>Server</h2>
+      <h2>Realms</h2>
       <p class="section-description">
-        Configure core server settings such as the display name, authentication host, and allowed origins.
+        Each realm is one passkey rp-id with its own display name, optional dedicated auth host, and allowed origins (including Related Origin Requests origins on unrelated domains). Changes apply immediately.
       </p>
     </div>
-    <button @click="$emit('openServerConfig')">⚙ Server Options</button>
+    <div class="section-actions">
+      <button @click="$emit('createRealm')">+ Add Realm</button>
+    </div>
+    <table class="org-table">
+      <thead>
+        <tr>
+          <th>Realm</th>
+          <th>Auth Host</th>
+          <th class="center">Origins</th>
+          <th class="center"></th>
+        </tr>
+      </thead>
+      <tbody>
+        <tr v-if="!realms || realms.length === 0">
+          <td colspan="4" class="center muted">No realms configured</td>
+        </tr>
+        <tr v-for="realm in realms" :key="realm.rp_id">
+          <td class="perm-name-cell">
+            <div class="perm-title">
+              <a :href="'#realm:' + realm.rp_id" @click.prevent="$emit('openRealm', realm)">{{ realm.rp_name || realm.rp_id }}</a>
+              <span v-if="realm.is_default" class="badge badge-current">Default</span>
+            </div>
+            <div class="perm-id-info">
+              <span class="id-text">{{ realm.rp_id }}</span>
+            </div>
+          </td>
+          <td class="realm-auth-host">
+            <span v-if="realm.effective_auth_host">{{ realm.effective_auth_host }}<span v-if="!realm.auth_host" class="muted"> (shared)</span></span>
+            <span v-else class="muted">—</span>
+          </td>
+          <td class="center">{{ realm.origins?.length || 0 }}</td>
+          <td class="center">
+            <button v-if="!realm.is_default" @click="$emit('deleteRealm', realm)" class="icon-btn delete-icon" aria-label="Delete realm" title="Delete realm">❌</button>
+          </td>
+        </tr>
+      </tbody>
+    </table>
   </div>
 </template>
 
@@ -459,7 +496,10 @@ defineExpose({ focusFirstElement })
 .oidc-clients-section .section-header { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: var(--space-md); }
 .client-groups { font-size: 0.85rem; color: var(--color-text-muted); max-width: 200px; font-family: var(--font-mono, monospace); }
 
-/* Server Options Section */
-.server-options-section { margin-top: var(--space-2xl); }
-.server-options-section .section-header { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: var(--space-md); }
+/* Realms Section */
+.realms-section { margin-top: var(--space-2xl); }
+.realms-section .section-header { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: var(--space-md); }
+.realms-section .section-actions { margin-bottom: var(--space-md); }
+.realm-auth-host { font-family: var(--font-mono, monospace); font-size: 0.85rem; }
+.realms-section .perm-title { display: flex; align-items: center; gap: 0.5rem; }
 </style>
diff --git a/frontend/src/assets/style.css b/frontend/src/assets/style.css
index 5f8d62d..435760a 100644
--- a/frontend/src/assets/style.css
+++ b/frontend/src/assets/style.css
@@ -804,6 +804,28 @@ th {
   border: 1px solid var(--color-border);
 }
 
+.badge-realm {
+  font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
+  font-size: 0.75rem;
+}
+
+.realm-enroll-notice {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  justify-content: space-between;
+  gap: 0.75rem;
+  padding: 0.75rem 1rem;
+  margin-bottom: 1rem;
+  border: 1px solid var(--color-accent);
+  border-radius: var(--radius-sm);
+  background: var(--color-surface-subtle);
+}
+
+.realm-enroll-notice p {
+  margin: 0;
+}
+
 
 .session-meta-info {
   font-size: 0.75rem;
diff --git a/frontend/src/components/CredentialList.vue b/frontend/src/components/CredentialList.vue
index 6c06315..945bff2 100644
--- a/frontend/src/components/CredentialList.vue
+++ b/frontend/src/components/CredentialList.vue
@@ -32,6 +32,7 @@
           </div>
           <h4 class="item-title">{{ getCredentialAuthName(credential) }}</h4>
           <div class="item-actions">
+            <span v-if="credential.rp_id && settings?.rp_id && credential.rp_id !== settings.rp_id" class="badge badge-realm" :title="`Passkey registered for ${credential.rp_id}`">{{ credential.rp_id }}</span>
             <span v-if="credential.is_current_session && !hoveredCredentialUuid && !hoveredSessionCredentialUuid" class="badge badge-current">Current</span>
             <span v-else-if="hoveredCredentialUuid === credential.credential" class="badge badge-current">Selected</span>
             <span v-else-if="hoveredSessionCredentialUuid === credential.credential" class="badge badge-current">Linked</span>
@@ -61,8 +62,13 @@
 </template>
 
 <script setup>
+import { onMounted, ref } from 'vue'
 import { formatDate } from '@/utils/helpers'
 import { navigateGrid, handleEscape, handleDeleteKey, getDirection } from '@/utils/keynav'
+import { getSettings } from '@/utils/settings'
+
+const settings = ref(null)
+onMounted(async () => { settings.value = await getSettings() })
 
 const props = defineProps({
   credentials: { type: Array, default: () => [] },
diff --git a/frontend/src/components/ProfileView.vue b/frontend/src/components/ProfileView.vue
index eecf57a..a007379 100644
--- a/frontend/src/components/ProfileView.vue
+++ b/frontend/src/components/ProfileView.vue
@@ -54,6 +54,10 @@
         <p class="section-description">Ideally have at least two passkeys in case you lose one. More than one user can be registered on the same device, giving you a choice at login. <a href="https://bitwarden.com/pricing/" target="_blank" rel="noopener noreferrer">Bitwarden</a> can sync one passkey to all your devices. Other secure options include <b>local passkeys</b>, as well as hardware keys such as <a href="https://www.yubico.com" target="_blank" rel="noopener noreferrer">YubiKey</a>. Cloud sync via Google, Microsoft or iCloud is discouraged.</p>
       </div>
       <div class="section-body">
+        <div v-if="missingRealmPasskey" class="realm-enroll-notice">
+          <p>You don't have a passkey for <strong>{{ rpName }}</strong> ({{ authStore.settings.rp_id }}) yet. Add one to log in here directly.</p>
+          <button @click="addNewCredential" class="btn-primary">Add Passkey for {{ authStore.settings.rp_id }}</button>
+        </div>
         <CredentialList
           ref="credentialList"
           :credentials="credentials"
@@ -410,6 +414,11 @@ const hasMultipleSessions = computed(() => Object.keys(sessions.value).length >
 const credentials = computed(() =>
   Object.entries(authStore.userInfo.credentials).map(([uuid, c]) => ({ ...c, credential: uuid }))
 )
+const missingRealmPasskey = computed(() => {
+  const rpId = authStore.settings?.rp_id
+  if (!rpId) return false
+  return !credentials.value.some(c => c.rp_id === rpId)
+})
 const useWideLayout = computed(() => {
   // Check if any single site has more than 8 sessions
   const groups = {}
diff --git a/frontend/src/components/RemoteAuthPermit.vue b/frontend/src/components/RemoteAuthPermit.vue
index b867aaa..a508237 100644
--- a/frontend/src/components/RemoteAuthPermit.vue
+++ b/frontend/src/components/RemoteAuthPermit.vue
@@ -53,6 +53,7 @@
       <!-- Device info display (shown when 3 words match a request) -->
       <div v-else-if="deviceInfo" class="device-info">
         <p class="device-permit-text">Permit {{ deviceInfo.action === 'register' ? 'registration' : 'login' }} to <strong>{{ deviceInfo.host }}</strong></p>
+        <p v-if="crossRealmNotice" class="device-meta realm-notice">on <strong>{{ deviceInfo.rp_name || deviceInfo.rp_id }}</strong><template v-if="deviceInfo.rp_name"> ({{ deviceInfo.rp_id }})</template></p>
         <p class="device-meta">{{ deviceInfo.user_agent_pretty || '—' }}</p>
 
         <p v-if="error" class="error-message">{{ error }}</p>
@@ -122,6 +123,13 @@ watch(deviceInfo, (newVal) => {
   emit('deviceInfoVisible', !!newVal)
 })
 
+const crossRealmNotice = computed(() => {
+  const info = deviceInfo.value
+  if (!info?.rp_id) return false
+  const ownRpId = settings.value?.rp_id
+  return ownRpId ? info.rp_id !== ownRpId : true
+})
+
 const hasInvalidWord = ref(false)
 const serverError = ref(false)
 const cursorPos = ref(0)
@@ -613,7 +621,9 @@ async function lookupDeviceInfo() {
         host: res.host,
         user_agent_pretty: res.user_agent_pretty,
         client_ip: res.client_ip,
-        action: res.action || 'login'
+        action: res.action || 'login',
+        rp_id: res.rp_id || null,
+        rp_name: res.rp_name || null
       }
       lastLookedUpCode = currentCode
       nextTick(() => { submitBtnRef.value?.focus() })
@@ -937,6 +947,12 @@ defineExpose({ reset, deny, code, handleInput, loading, error })
   font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
 }
 
+.realm-notice {
+  color: var(--color-text);
+  font-family: inherit;
+  font-size: 0.9rem;
+}
+
 .error-message {
   margin: 0.5rem 0 0;
   font-size: 0.875rem;
diff --git a/frontend/src/stores/auth.js b/frontend/src/stores/auth.js
index 2b2f56b..6b79c02 100644
--- a/frontend/src/stores/auth.js
+++ b/frontend/src/stores/auth.js
@@ -83,8 +83,8 @@ export const useAuthStore = defineStore('auth', {
       if (!this.userInfo) this.currentView = 'login'
       else this.currentView = 'profile'
     },
-    async loadSettings() {
-      this.settings = await getSettings()
+    async loadSettings(force = false) {
+      this.settings = await getSettings(force)
     },
     async loadUserInfo() {
       try {
diff --git a/frontend/src/utils/settings.js b/frontend/src/utils/settings.js
index 47cc3e8..ce26ea5 100644
--- a/frontend/src/utils/settings.js
+++ b/frontend/src/utils/settings.js
@@ -3,7 +3,8 @@ let _settings = null
 
 export function getSettingsCached() { return _settings }
 
-export async function getSettings() {
+export async function getSettings(force = false) {
+  if (force) { _settings = null; _settingsPromise = null }
   if (_settings) return _settings
   if (_settingsPromise) return _settingsPromise
   _settingsPromise = fetch('/auth/api/settings')