diff --git a/app/cabinet/routes/landing.py b/app/cabinet/routes/landing.py
index 8ec7ba81..50168a2a 100644
--- a/app/cabinet/routes/landing.py
+++ b/app/cabinet/routes/landing.py
@@ -23,7 +23,7 @@ from app.services.guest_purchase_service import (
 )
 from app.services.payment_method_config_service import _get_method_defaults
 from app.services.payment_service import PaymentService
-from app.utils.cache import RateLimitCache
+from app.utils.cache import RateLimitCache, cache
 
 
 logger = structlog.get_logger(__name__)
@@ -128,6 +128,9 @@ class PurchaseRequest(BaseModel):
     gift_recipient_type: str | None = Field(default=None, pattern=r'^(email|telegram)$')
     gift_recipient_value: str | None = Field(default=None, max_length=255)
     gift_message: str | None = Field(default=None, max_length=1000)
+    yandex_cid: str | None = Field(default=None, max_length=128, pattern=r'^[A-Za-z0-9._:-]{4,128}$')
+    referrer: str | None = Field(default=None, max_length=500)
+    subid: str | None = Field(default=None, max_length=255)
 
     @model_validator(mode='after')
     def validate_contacts(self) -> 'PurchaseRequest':
@@ -654,6 +657,8 @@ async def create_landing_purchase(
         gift_recipient_type=body.gift_recipient_type,
         gift_recipient_value=body.gift_recipient_value,
         gift_message=body.gift_message,
+        subid=body.subid,
+        referrer=body.referrer,
         commit=False,
     )
 
@@ -706,6 +711,20 @@ async def create_landing_purchase(
     await db.commit()
     await db.refresh(purchase)
 
+    # Persist Yandex CID in cache so fulfill_purchase can link it to the user later
+    if body.yandex_cid and settings.YANDEX_OFFLINE_CONV_ENABLED:
+        try:
+            await cache.set(f'yacid:purchase:{purchase.token}', body.yandex_cid, expire=86400)
+        except Exception:
+            pass
+
+    # Persist subid in cache for S2S postback
+    if body.subid:
+        try:
+            await cache.set(f'subid:purchase:{purchase.token}', body.subid, expire=86400)
+        except Exception:
+            pass
+
     return PurchaseResponse(
         purchase_token=purchase.token,
         payment_url=payment_url,
diff --git a/app/services/guest_purchase_service.py b/app/services/guest_purchase_service.py
index d98ce0ac..dc33ac6a 100644
--- a/app/services/guest_purchase_service.py
+++ b/app/services/guest_purchase_service.py
@@ -145,6 +145,8 @@ async def create_purchase(
     gift_recipient_value: str | None = None,
     gift_message: str | None = None,
     source: str = 'landing',
+    subid: str | None = None,
+    referrer: str | None = None,
     buyer_user_id: int | None = None,
     commit: bool = True,
 ) -> GuestPurchase:
@@ -152,6 +154,8 @@ async def create_purchase(
     purchase = await create_guest_purchase(
         db,
         commit=commit,
+        subid=subid,
+        referrer=referrer,
         landing_id=landing.id if landing else None,
         tariff_id=tariff.id,
         period_days=period_days,
@@ -438,6 +442,20 @@ async def fulfill_purchase(
         purchase.status = GuestPurchaseStatus.DELIVERED.value
         purchase.user_id = user.id
         purchase.delivered_at = datetime.now(UTC)
+
+        # Extract subid from Redis cache (saved at purchase creation)
+        try:
+            from app.utils.cache import cache
+
+            _cached_subid = await cache.get(f'subid:purchase:{purchase.token}')
+            if _cached_subid:
+                purchase.subid = _cached_subid if isinstance(_cached_subid, str) else _cached_subid.decode()
+                from app.database.crud.yandex_client_id import upsert_subid
+
+                await upsert_subid(db, user.id, purchase.subid, source='landing')
+        except Exception:
+            pass
+
         if recipient_type == 'email' and not purchase.is_gift and is_new_account:
             purchase.auto_login_token = create_auto_login_token(user.id)
 
@@ -463,6 +481,55 @@ async def fulfill_purchase(
             except Exception:
                 logger.exception('Failed to create transaction for guest purchase', purchase_id=purchase.id)
 
+        # Save Yandex CID from Redis → DB (enables on_registration/on_purchase to use it)
+        try:
+            from app.services import yandex_offline_conv_service as yandex_conv
+            from app.utils.cache import cache
+
+            _cached_cid = await cache.get(f'yacid:purchase:{purchase.token}')
+            if _cached_cid:
+                await yandex_conv.store_cid(db, user.id, _cached_cid, source='landing')
+                await db.commit()
+        except Exception:
+            logger.debug('Failed to save CID from Redis')
+
+        # Registration event (new accounts only) + S2S postback
+        if is_new_account:
+            try:
+                from app.services import yandex_offline_conv_service as yandex_conv
+
+                await yandex_conv.on_registration(db, user.id)
+            except Exception:
+                logger.debug('Yandex on_registration hook error')
+
+            try:
+                from app.database.crud.yandex_client_id import get_subid
+                from app.services.s2s_postback_service import send_postback
+
+                _subid = purchase.subid or await get_subid(db, user.id)
+                if _subid:
+                    await send_postback('registration', _subid, user_id=user.id)
+            except Exception:
+                logger.debug('S2S postback registration hook error')
+
+        # Purchase event + S2S postback (always for paid purchases)
+        try:
+            from app.services import yandex_offline_conv_service as yandex_conv
+
+            await yandex_conv.on_purchase(db, user.id, purchase.amount_kopeks)
+        except Exception:
+            logger.debug('Yandex on_purchase hook error')
+
+        try:
+            from app.database.crud.yandex_client_id import get_subid
+            from app.services.s2s_postback_service import send_postback
+
+            _subid = purchase.subid or await get_subid(db, user.id)
+            if _subid:
+                await send_postback('purchase', _subid, amount=purchase.amount_kopeks / 100, user_id=user.id)
+        except Exception:
+            logger.debug('S2S postback purchase hook error')
+
         try:
             await send_guest_notification(
                 purchase,