diff --git a/SVSim.EmulatedEntrypoint/Controllers/SpotCardExchangeController.cs b/SVSim.EmulatedEntrypoint/Controllers/SpotCardExchangeController.cs
index d5d8ec9..c5be16e 100644
--- a/SVSim.EmulatedEntrypoint/Controllers/SpotCardExchangeController.cs
+++ b/SVSim.EmulatedEntrypoint/Controllers/SpotCardExchangeController.cs
@@ -4,6 +4,7 @@ using SVSim.Database;
 using SVSim.Database.Enums;
 using SVSim.Database.Models;
 using SVSim.Database.Services;
+using SVSim.Database.Services.Inventory;
 using SVSim.EmulatedEntrypoint.Models.Dtos;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Requests;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Requests.SpotCardExchange;
@@ -14,8 +15,7 @@ namespace SVSim.EmulatedEntrypoint.Controllers;
 /// <summary>
 /// /spot_card_exchange/* — trade spot points for individual cards from the rotating exchange
 /// pool. Spot points are earned from battles/missions (not implemented here — earners live in
-/// battle/mission finish reward emitters via <see cref="RewardGrantService"/> +
-/// <see cref="UserGoodsType.SpotCardPoint"/>).
+/// battle/mission finish reward emitters via <see cref="UserGoodsType.SpotCardPoint"/>).
 /// </summary>
 [Route("spot_card_exchange")]
 public class SpotCardExchangeController : SVSimController
@@ -28,16 +28,14 @@ public class SpotCardExchangeController : SVSimController
     private const int PreReleaseLimit = 2;
 
     private readonly SVSimDbContext _db;
-    private readonly RewardGrantService _rewards;
+    private readonly IInventoryService _inv;
     private readonly TimeProvider _time;
-    private readonly ICurrencySpendService _spend;
 
-    public SpotCardExchangeController(SVSimDbContext db, RewardGrantService rewards, TimeProvider time, ICurrencySpendService spend)
+    public SpotCardExchangeController(SVSimDbContext db, IInventoryService inv, TimeProvider time)
     {
         _db = db;
-        _rewards = rewards;
+        _inv = inv;
         _time = time;
-        _spend = spend;
     }
 
     [HttpPost("top")]
@@ -126,14 +124,14 @@ public class SpotCardExchangeController : SVSimController
                 return BadRequest(new { error = "pre_release_limit_reached" });
         }
 
-        var viewer = await LoadViewerGraphAsync(viewerId);
+        await using var tx = await _inv.BeginAsync(viewerId);
 
         var rewardList = new List<RewardListEntry>();
 
         // Debit spot points. Client-supplied exchange_point isn't authoritative — server uses
         // catalog price. Mirroring the build_deck/sleeve convention: post-state currency entry
         // first, then grants.
-        var spotRes = await _spend.TrySpendAsync(viewer, SpendCurrency.SpotPoint, entry.ExchangePoint);
+        var spotRes = await tx.TrySpendAsync(SpendCurrency.SpotPoint, entry.ExchangePoint);
         if (!spotRes.Success)
             return BadRequest(new { error = "insufficient_spot_points" });
         rewardList.Add(new RewardListEntry
@@ -143,8 +141,8 @@ public class SpotCardExchangeController : SVSimController
             RewardNum = checked((int)spotRes.PostStateTotal),
         });
 
-        // Grant the card itself via the existing card dispatcher (handles cosmetic cascade).
-        var granted = await _rewards.ApplyAsync(viewer, UserGoodsType.Card, entry.Id, 1);
+        // Grant the card itself via the inventory tx (handles cosmetic cascade).
+        var granted = await tx.GrantAsync(UserGoodsType.Card, entry.Id, 1);
         foreach (var g in granted)
         {
             rewardList.Add(new RewardListEntry
@@ -163,7 +161,7 @@ public class SpotCardExchangeController : SVSimController
             ExchangedAt = _time.GetUtcNow().UtcDateTime,
         });
 
-        await _db.SaveChangesAsync();
+        await tx.CommitAsync();
         return new SpotCardExchangeResponse { RewardList = rewardList };
     }
 
@@ -182,14 +180,4 @@ public class SpotCardExchangeController : SVSimController
         return 0;
     }
 
-    private Task<Viewer> LoadViewerGraphAsync(long viewerId) => _db.Viewers
-        .Include(v => v.Cards).ThenInclude(c => c.Card)
-        .Include(v => v.Sleeves)
-        .Include(v => v.Emblems)
-        .Include(v => v.LeaderSkins)
-        .Include(v => v.Degrees)
-        .Include(v => v.MyPageBackgrounds)
-        .Include(v => v.Items).ThenInclude(i => i.Item)
-        .AsSplitQuery()
-        .FirstAsync(v => v.Id == viewerId);
 }