diff --git a/apps/web/src/lib/kiloclaw/sandbox-id.ts b/apps/web/src/lib/kiloclaw/sandbox-id.ts
deleted file mode 100644
index 17040adf7d..0000000000
--- a/apps/web/src/lib/kiloclaw/sandbox-id.ts
+++ /dev/null
@@ -1,52 +0,0 @@
-/**
- * Derive a deterministic sandbox ID from a user ID.
- *
- * Identical logic to kiloclaw/src/auth/sandbox-id.ts — base64url encoding
- * of the UTF-8 bytes of the userId. Used by the Next.js backend to
- * pre-generate sandbox_id when inserting the instance row into Postgres.
- *
- * Must stay in sync with the worker's sandboxIdFromUserId.
- */
-
-const MAX_SANDBOX_ID_LENGTH = 63;
-
-function bytesToBase64url(bytes: Uint8Array): string {
-  const binString = Array.from(bytes, b => String.fromCodePoint(b)).join('');
-  return btoa(binString).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
-}
-
-export function sandboxIdFromUserId(userId: string): string {
-  const bytes = new TextEncoder().encode(userId);
-  const encoded = bytesToBase64url(bytes);
-  if (encoded.length > MAX_SANDBOX_ID_LENGTH) {
-    throw new Error(
-      `userId too long: encoded sandboxId would be ${encoded.length} chars (max ${MAX_SANDBOX_ID_LENGTH})`
-    );
-  }
-  return encoded;
-}
-
-// ─── Instance-scoped identity ───────────────────────────────────────
-// Canonical implementation lives in @kilocode/worker-utils/instance-id.
-// Inlined here because Next.js moduleResolution can't resolve the
-// worker-utils subpath export. Keep in sync with worker-utils/src/instance-id.ts.
-
-const UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/;
-
-export function isValidInstanceId(id: string): boolean {
-  return UUID_RE.test(id);
-}
-
-export function sandboxIdFromInstanceId(instanceId: string): string {
-  if (!isValidInstanceId(instanceId)) {
-    throw new Error('Invalid instanceId: must be a UUID');
-  }
-  const hex = instanceId.replace(/-/g, '');
-  const prefixed = `ki_${hex}`;
-  if (prefixed.length > MAX_SANDBOX_ID_LENGTH) {
-    throw new Error(
-      `instanceId too long: prefixed sandboxId would be ${prefixed.length} chars (max ${MAX_SANDBOX_ID_LENGTH})`
-    );
-  }
-  return prefixed;
-}
diff --git a/apps/web/src/routers/kiloclaw-billing-router.test.ts b/apps/web/src/routers/kiloclaw-billing-router.test.ts
index e2b207e2cf..718324f1be 100644
--- a/apps/web/src/routers/kiloclaw-billing-router.test.ts
+++ b/apps/web/src/routers/kiloclaw-billing-router.test.ts
@@ -29,7 +29,7 @@ import {
   user_affiliate_events,
 } from '@kilocode/db/schema';
 import { eq } from 'drizzle-orm';
-import { sandboxIdFromUserId } from '@/lib/kiloclaw/sandbox-id';
+import { sandboxIdFromUserId } from '@kilocode/worker-utils/sandbox-id';
 import { createOrganization } from '@/lib/organizations/organizations';
 import { insertTestUser } from '@/tests/helpers/user.helper';
 import type { User } from '@kilocode/db/schema';