diff --git a/backend/src/routes/netup.ts b/backend/src/routes/netup.ts
index 0090e8a..3e7115e 100644
--- a/backend/src/routes/netup.ts
+++ b/backend/src/routes/netup.ts
@@ -318,7 +318,7 @@ const netup: FastifyPluginAsync = async (fastify) => {
       if (!room) return reply.code(404).send({ error: 'Room not found' })
 
       const result = await notifyNetupCheckinInternal(
-        hotelId, room_id, room.number, 'Тестовый гость', 'TEST-' + room.number,
+        hotelId, room_id, room.number, 'Тестовый гость', '99999999',
       )
       if (result.ok) return { ok: true, message: `Check-in отправлен в NetUP (номер ${result.netupRoom})` }
       return reply.code(502).send({ error: result.error ?? 'Ошибка' })
@@ -368,8 +368,10 @@ async function notifyNetupCheckinInternal(
   const url  = `${base}/mw/api/hotel-room/${encodeURIComponent(mapping.netup_room_number)}/check-in`
   const cred = Buffer.from(`${cfg.username}:${cfg.password}`).toString('base64')
 
-  // NetUP expects reservation_id as a string
-  const requestBody = { reservation_id: reservationId, name: guestName, language: language ?? cfg.default_language }
+  // NetUP expects reservation_id as a numeric string (parses with strconv.Atoi)
+  // Convert UUID to a stable numeric string by taking first 8 hex chars → decimal
+  const resIdStr = String(parseInt(reservationId.replace(/-/g, '').slice(0, 8), 16) % 100000000)
+  const requestBody = { reservation_id: resIdStr, name: guestName, language: language ?? cfg.default_language }
 
   try {
     const res = await fetch(url, {