diff --git a/frontend/src/lib/api/endpoints/grants.ts b/frontend/src/lib/api/endpoints/grants.ts
index 6c880e8a..cc96c0e1 100644
--- a/frontend/src/lib/api/endpoints/grants.ts
+++ b/frontend/src/lib/api/endpoints/grants.ts
@@ -7,7 +7,9 @@ import type { ResourceBody, ResourcePage } from './resources';
 const JSON_HEADERS = { 'Content-Type': 'application/json' };
 
 export type SubjectType = 'user' | 'group' | 'email' | 'token';
-export type ShareRole = 'viewer' | 'editor' | 'admin';
+/** Roles the share UI exposes. The backend role enum also has `commenter` and
+ * `contributor`, which {@link displayRole} collapses to the nearest of these. */
+export type ShareRole = 'viewer' | 'editor' | 'owner';
 
 export interface GrantSubject {
 	type: SubjectType;
@@ -25,13 +27,17 @@ export type GrantSubjectInput =
 	| { type: 'token'; id: string }
 	| { type: 'email'; email: string };
 
-/** One grant carries a single permission; a subject's role is derived from all of theirs. */
+/**
+ * One role grant for a (subject, resource). Role-keyed since the role-grants
+ * migration: each row carries an explicit `role` (the backend enum, which may
+ * be `owner`/`editor`/`viewer`/`commenter`/`contributor`).
+ */
 export interface Grant {
 	id: string;
 	granted_at?: string;
 	granted_by?: string;
 	subject: GrantSubject;
-	permission: string;
+	role: string;
 	resource: { type: ItemType; id: string };
 	expires_at?: string | null;
 }
@@ -56,10 +62,16 @@ export interface CreateGrantResponse {
 	notification: NotifyOutcomeSet;
 }
 
-export function roleFromPermissions(perms: Iterable<string>): ShareRole {
-	const set = new Set(perms);
-	if (set.has('delete') || set.has('share')) return 'admin';
-	if (set.has('create') || set.has('update')) return 'editor';
+/**
+ * Map a backend role string to the role the UI exposes. The server may emit the
+ * full enum (`owner`/`editor`/`viewer`/`commenter`/`contributor`); the picker
+ * only shows Owner/Editor/Viewer, so collapse the two unexposed roles to their
+ * closest neighbour rather than render an unknown option.
+ */
+export function displayRole(role: string | undefined): ShareRole {
+	if (role === 'owner' || role === 'editor' || role === 'viewer') return role;
+	if (role === 'contributor') return 'editor';
+	if (role === 'commenter') return 'viewer';
 	return 'viewer';
 }
 
diff --git a/frontend/src/lib/components/ShareDialog.svelte b/frontend/src/lib/components/ShareDialog.svelte
index a054e141..8dbd6403 100644
--- a/frontend/src/lib/components/ShareDialog.svelte
+++ b/frontend/src/lib/components/ShareDialog.svelte
@@ -10,10 +10,10 @@
 	import {
 		createGrant,
 		expiryToIso,
+		displayRole,
 		fetchGrantsForResource,
 		notifyGrantRecipient,
 		revokeGrant,
-		roleFromPermissions,
 		updateGrantRole,
 		type Grant,
 		type GrantSubject,
@@ -51,11 +51,11 @@
 	let directoryAvailable = $state(true);
 
 	const ROLES: { v: ShareRole; l: string; icon: string }[] = [
-		{ v: 'admin', l: t('share.role.canManage', 'Can manage'), icon: 'crown' },
+		{ v: 'owner', l: t('share.role.canManage', 'Can manage'), icon: 'crown' },
 		{ v: 'editor', l: t('share.role.canEdit', 'Can edit'), icon: 'pencil-alt' },
 		{ v: 'viewer', l: t('share.role.canView', 'Can view'), icon: 'eye' }
 	];
-	const ROLE_ORDER: ShareRole[] = ['admin', 'editor', 'viewer'];
+	const ROLE_ORDER: ShareRole[] = ['owner', 'editor', 'viewer'];
 	function roleLabel(r: ShareRole): string {
 		return ROLES.find((x) => x.v === r)?.l ?? r;
 	}
@@ -89,13 +89,20 @@
 	function groupGrants(grants: Grant[]): Member[] {
 		const bySubject = new Map<
 			string,
-			{ subject: GrantSubject; perms: string[]; ids: string[]; expiry: string | null }
+			{ subject: GrantSubject; role: ShareRole; ids: string[]; expiry: string | null }
 		>();
 		for (const g of grants) {
 			if (g.subject.type === 'token') continue;
 			const key = `${g.subject.type}:${g.subject.id}`;
-			const entry = bySubject.get(key) ?? { subject: g.subject, perms: [], ids: [], expiry: null };
-			entry.perms.push(g.permission);
+			const entry = bySubject.get(key) ?? {
+				subject: g.subject,
+				role: 'viewer' as ShareRole,
+				ids: [],
+				expiry: null
+			};
+			// Role-grants emit one row per (subject, resource), so the row's role
+			// is the subject's role directly.
+			entry.role = displayRole(g.role);
 			entry.ids.push(g.id);
 			if (g.expires_at && !entry.expiry) entry.expiry = isoToDate(g.expires_at);
 			bySubject.set(key, entry);
@@ -103,7 +110,7 @@
 		return [...bySubject.values()].map((e) => ({
 			subject: e.subject,
 			recipient: resolveRecipient(e.subject.type as 'user' | 'group', e.subject.id),
-			role: roleFromPermissions(e.perms),
+			role: e.role,
 			grantIds: e.ids,
 			notifyGrantId: e.ids[0],
 			expiry: e.expiry,
diff --git a/frontend/src/routes/shared/+page.svelte b/frontend/src/routes/shared/+page.svelte
index a86ba371..d333ecb7 100644
--- a/frontend/src/routes/shared/+page.svelte
+++ b/frontend/src/routes/shared/+page.svelte
@@ -4,6 +4,7 @@
 	import { goto } from '$app/navigation';
 	import { onMount } from 'svelte';
 	import {
+		displayRole,
 		expiryToIso,
 		fetchMyShares,
 		notifyGrantRecipient,
@@ -33,12 +34,12 @@
 	];
 
 	const ROLES: { v: ShareRole; l: string; icon: string }[] = [
-		{ v: 'admin', l: t('share.role.canManage', 'Can manage'), icon: 'crown' },
+		{ v: 'owner', l: t('share.role.canManage', 'Can manage'), icon: 'crown' },
 		{ v: 'editor', l: t('share.role.canEdit', 'Can edit'), icon: 'pencil-alt' },
 		{ v: 'viewer', l: t('share.role.canView', 'Can view'), icon: 'eye' }
 	];
 	function roleMeta(r: string) {
-		return ROLES.find((x) => x.v === r) ?? ROLES[2];
+		return ROLES.find((x) => x.v === displayRole(r)) ?? ROLES[2];
 	}
 
 	let raw = $state<OutgoingGrantItem[]>([]);