diff --git a/AccessQueueService/Data/TakeANumberAccessQueueRepo.cs b/AccessQueueService/Data/TakeANumberAccessQueueRepo.cs
index f86c22d..ad45a83 100644
--- a/AccessQueueService/Data/TakeANumberAccessQueueRepo.cs
+++ b/AccessQueueService/Data/TakeANumberAccessQueueRepo.cs
@@ -156,7 +156,7 @@ namespace AccessQueueService.Data
             foreach (var queueItem in state.AccessQueue)
             {
                 _queueNumbers.Add(queueItem.Value.UserId, queueItem.Key);
-                _nextUnusedTicket = Math.Max(_nextUnusedTicket, queueItem.Key);
+                _nextUnusedTicket = Math.Max(_nextUnusedTicket, queueItem.Key + 1);
                 _nowServing = Math.Min(_nowServing, queueItem.Key);
             }
 
diff --git a/AccessQueueServiceTests/AccessQueueRepoTests.cs b/AccessQueueServiceTests/AccessQueueRepoTests.cs
index f80a9a3..3f56f1a 100644
--- a/AccessQueueServiceTests/AccessQueueRepoTests.cs
+++ b/AccessQueueServiceTests/AccessQueueRepoTests.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using System.Text.Json;
 using System.Threading.Tasks;
 using AccessQueueService.Data;
 using AccessQueueService.Models;
@@ -235,5 +236,50 @@ namespace AccessQueueServiceTests
             Assert.Equal(0, _repo.GetRequestsAhead("first"));
             Assert.Equal(2, _repo.GetRequestsAhead("third"));
         }
+
+        [Fact]
+        public void ToState_ReturnsAccurateJson()
+        {
+            var ticketWithAccess = new AccessTicket { UserId = "access", ExpiresOn = DateTime.UtcNow.AddMinutes(1), LastActive = DateTime.UtcNow };
+            var ticketWithoutAccess = new AccessTicket { UserId = "noAccess", LastActive = DateTime.UtcNow };
+
+            _repo.UpsertTicket(ticketWithAccess);
+            _repo.Enqueue(ticketWithoutAccess);
+
+            string stateJson = _repo.ToState();
+            var state = JsonSerializer.Deserialize<TakeANumberAccessQueueRepoState>(stateJson);
+
+            Assert.NotNull(state?.AccessQueue);
+            Assert.NotNull(state?.AccessTickets);
+            Assert.Single(state!.AccessTickets);
+            Assert.Single(state!.AccessQueue);
+
+            Assert.Equal(ticketWithAccess.UserId, state.AccessTickets.First().Key);
+            Assert.Equal(ticketWithAccess.ExpiresOn, state.AccessTickets.First().Value.ExpiresOn);
+            Assert.Equal(ticketWithAccess.LastActive, state.AccessTickets.First().Value.LastActive);
+
+            Assert.Equal(ticketWithoutAccess.UserId, state.AccessQueue.First().Value.UserId);
+            Assert.Equal(ticketWithoutAccess.LastActive, state.AccessQueue.First().Value.LastActive);
+        }
+
+        [Fact]
+        public void FromState_DeserializesJsonCorrectly()
+        {
+            var ticketWithAccess = new AccessTicket { UserId = "access", ExpiresOn = DateTime.UtcNow.AddMinutes(1), LastActive = DateTime.UtcNow };
+            var ticketWithoutAccess = new AccessTicket { UserId = "noAccess", LastActive = DateTime.UtcNow };
+
+            _repo.UpsertTicket(ticketWithAccess);
+            _repo.Enqueue(ticketWithoutAccess);
+
+            string stateJson = _repo.ToState();
+            var deserializedRepo = TakeANumberAccessQueueRepo.FromState(stateJson);
+
+            Assert.Equal(1, deserializedRepo.GetUnexpiredTicketsCount());
+            Assert.Equal(1, deserializedRepo.GetQueueCount());
+
+            Assert.Equal(deserializedRepo.GetTicket("access")!.ExpiresOn, ticketWithAccess.ExpiresOn);
+            Assert.Null(deserializedRepo.GetTicket("noAccess"));
+            Assert.Equal(0, deserializedRepo.GetRequestsAhead("noAccess"));
+        }
     }
 }