diff --git a/shared/database/src/schema.ts b/shared/database/src/schema.ts
index 7a9bfc5..5fd485d 100644
--- a/shared/database/src/schema.ts
+++ b/shared/database/src/schema.ts
@@ -550,7 +550,7 @@ export const anonymous_devices = pgTable(
   'anonymous_devices',
   {
     id: serial('id').primaryKey(),
-    deviceId: varchar('device_id', { length: 255 }).notNull().unique(),
+    deviceId: varchar('device_id', { length: 255 }).notNull(),
     createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
     lastSeenAt: timestamp('last_seen_at', { withTimezone: true }).notNull().defaultNow(),
     blocked: boolean('blocked').notNull().default(false),
diff --git a/tests/unit/database/schema.anonymous-devices.test.ts b/tests/unit/database/schema.anonymous-devices.test.ts
new file mode 100644
index 0000000..ca630d9
--- /dev/null
+++ b/tests/unit/database/schema.anonymous-devices.test.ts
@@ -0,0 +1,22 @@
+import { getTableConfig } from 'drizzle-orm/pg-core';
+import { anonymous_devices } from '../../../shared/database/src/schema';
+
+describe('anonymous_devices schema', () => {
+  it('should have exactly one uniqueness constraint on device_id', () => {
+    const config = getTableConfig(anonymous_devices);
+    const col = anonymous_devices.deviceId;
+
+    let uniqueCount = 0;
+
+    // .unique() on the column sets isUnique at the column level
+    if (col.isUnique) uniqueCount++;
+
+    // uniqueIndex() in the table's third argument appears in config.indexes
+    const uniqueIndexesOnDeviceId = config.indexes.filter(
+      (idx) => idx.config.unique && idx.config.columns.some((c) => 'name' in c && c.name === 'device_id')
+    );
+    uniqueCount += uniqueIndexesOnDeviceId.length;
+
+    expect(uniqueCount).toBe(1);
+  });
+});