diff --git a/src/data/database.ts b/src/data/database.ts
index d2d0462..78a721a 100644
--- a/src/data/database.ts
+++ b/src/data/database.ts
@@ -182,12 +182,37 @@ function initTables(db: Database.Database): void {
   `);
 }
 
+/**
+ * One-time backfill: existing `member` users created before the
+ * account-permissions feature are granted full access (all 5 capabilities +
+ * the `bots.all` marker), exactly once per database. Admins are skipped (they
+ * bypass permission checks). New members created after this runs are not
+ * affected — they get the basic tier via POST /api/users. A marker row in
+ * `schema_meta` makes this idempotent.
+ */
+export function backfillMemberPermissions(db: Database.Database): void {
+  db.exec(`CREATE TABLE IF NOT EXISTS schema_meta (key TEXT PRIMARY KEY, value TEXT)`);
+  const done = db.prepare("SELECT value FROM schema_meta WHERE key = 'perm_backfill_done'").get();
+  if (done) return;
+  const members = db.prepare("SELECT id FROM users WHERE role = 'member'").all() as { id: string }[];
+  const insCap = db.prepare("INSERT OR IGNORE INTO user_permissions (userId, permission) VALUES (?, ?)");
+  const tokens = ["player.control", "player.queue", "bot.manage", "platform.auth", "quality", "bots.all"];
+  const tx = db.transaction(() => {
+    for (const m of members) {
+      for (const t of tokens) insCap.run(m.id, t);
+    }
+    db.prepare("INSERT INTO schema_meta (key, value) VALUES ('perm_backfill_done', ?)").run(String(members.length));
+  });
+  tx();
+}
+
 export function createDatabase(dbPath: string): BotDatabase {
   const db = new Database(dbPath);
   db.pragma("journal_mode = WAL");
   db.pragma("foreign_keys = ON");
   initTables(db);
   migrateSchema(db);
+  backfillMemberPermissions(db);
 
   const insertHistory = db.prepare(`
     INSERT INTO play_history (botId, songId, songName, artist, album, platform, coverUrl)
diff --git a/src/data/permissions-migration.test.ts b/src/data/permissions-migration.test.ts
new file mode 100644
index 0000000..d290ce1
--- /dev/null
+++ b/src/data/permissions-migration.test.ts
@@ -0,0 +1,58 @@
+import { describe, it, expect, afterEach } from "vitest";
+import fs from "node:fs";
+import path from "node:path";
+import os from "node:os";
+import { createDatabase, backfillMemberPermissions, type BotDatabase } from "./database.js";
+import { createPermissionStore, CAPABILITIES } from "./permissions.js";
+
+describe("backfillMemberPermissions", () => {
+  let dbFile: string;
+  let db: BotDatabase;
+  function fresh() {
+    dbFile = path.join(os.tmpdir(), `mig-${Date.now()}-${Math.random().toString(36).slice(2)}.db`);
+    db = createDatabase(dbFile);
+  }
+  afterEach(() => {
+    db.close();
+    for (const s of ["", "-wal", "-shm"]) {
+      try {
+        fs.rmSync(dbFile + s, { force: true });
+      } catch {}
+    }
+  });
+
+  it("grants existing members full access + bots.all, skips admins, once", () => {
+    fresh();
+    // simulate a pre-feature DB: clear the marker that createDatabase set, add users, no perm rows
+    db.db.prepare("DELETE FROM schema_meta WHERE key = 'perm_backfill_done'").run();
+    const now = Date.now();
+    const ins = db.db.prepare(
+      "INSERT INTO users (id,username,passwordHash,createdAt,updatedAt,role) VALUES (?,?,?,?,?,?)"
+    );
+    ins.run("m1", "mem", "x", now, now, "member");
+    ins.run("a1", "adm", "x", now, now, "admin");
+
+    backfillMemberPermissions(db.db);
+
+    const store = createPermissionStore(db.db);
+    expect(store.getCapabilities("m1").sort()).toEqual([...CAPABILITIES].sort());
+    expect(store.getBotAccess("m1")).toBe("all");
+    expect(store.getCapabilities("a1")).toEqual([]);
+    expect(store.getBotAccess("a1")).toEqual([]);
+  });
+
+  it("is idempotent — running again does not change or re-grant", () => {
+    fresh();
+    db.db.prepare("DELETE FROM schema_meta WHERE key = 'perm_backfill_done'").run();
+    const now = Date.now();
+    db.db
+      .prepare("INSERT INTO users (id,username,passwordHash,createdAt,updatedAt,role) VALUES (?,?,?,?,?,?)")
+      .run("m1", "mem", "x", now, now, "member");
+    backfillMemberPermissions(db.db);
+    // member restricted afterwards
+    createPermissionStore(db.db).setPermissions("m1", { capabilities: [], bots: [] });
+    // second run must NOT re-grant (marker present)
+    backfillMemberPermissions(db.db);
+    expect(createPermissionStore(db.db).getCapabilities("m1")).toEqual([]);
+  });
+});