diff --git a/codex/sales.nim b/codex/sales.nim
index c81432ec..d8e8d3b0 100644
--- a/codex/sales.nim
+++ b/codex/sales.nim
@@ -153,7 +153,7 @@ proc load*(sales: Sales) {.async.} =
     agent.start(SaleUnknown())
     sales.agents.add agent
 
-proc onReservationAdded(sales: Sales, availability: Availability) {.async.} =
+proc onAvailabilityAdded(sales: Sales, availability: Availability) {.async.} =
   ## Query last 256 blocks for new requests, adding them to the queue. `push`
   ## checks for availability before adding to the queue. If processed, the
   ## sales agent will check if the slot is free.
@@ -384,9 +384,11 @@ proc startSlotQueue(sales: Sales) {.async.} =
 
   asyncSpawn slotQueue.start()
 
-  reservations.onReservationAdded =
-    proc(availability: Availability) {.async.} =
-      await sales.onReservationAdded(availability)
+  proc onAvailabilityAdded(availability: Availability) {.async.} =
+    await sales.onAvailabilityAdded(availability)
+
+  reservations.onAdded = onAvailabilityAdded
+  reservations.onMarkUnused = onAvailabilityAdded
 
 
 proc subscribe(sales: Sales) {.async.} =
diff --git a/codex/sales/reservations.nim b/codex/sales/reservations.nim
index e03f5dd8..09574baf 100644
--- a/codex/sales/reservations.nim
+++ b/codex/sales/reservations.nim
@@ -43,9 +43,10 @@ type
     used*: bool
   Reservations* = ref object
     repo: RepoStore
-    onReservationAdded: ?OnReservationAdded
+    onAdded: ?OnAvailabilityAdded
+    onMarkUnused: ?OnAvailabilityAdded
   GetNext* = proc(): Future[?Availability] {.upraises: [], gcsafe, closure.}
-  OnReservationAdded* = proc(availability: Availability): Future[void] {.upraises: [], gcsafe.}
+  OnAvailabilityAdded* = proc(availability: Availability): Future[void] {.upraises: [], gcsafe.}
   AvailabilityIter* = ref object
     finished*: bool
     next*: GetNext
@@ -111,9 +112,15 @@ proc readValue*[T: AvailabilityId](
   mixin readValue
   value = T reader.readValue(T.distinctBase)
 
-proc `onReservationAdded=`*(self: Reservations,
-                            onReservationAdded: OnReservationAdded) =
-  self.onReservationAdded = some onReservationAdded
+proc `onAdded=`*(self: Reservations,
+                            onAdded: OnAvailabilityAdded) =
+  self.onAdded = some onAdded
+
+proc `onMarkUnused=`*(
+  self: Reservations,
+  onMarkUnused: OnAvailabilityAdded
+) =
+  self.onMarkUnused = some onMarkUnused
 
 func key(id: AvailabilityId): ?!Key =
   (ReservationsKey / id.toArray.toHex)
@@ -217,13 +224,13 @@ proc reserve*(
 
     return failure(updateErr)
 
-  if onReservationAdded =? self.onReservationAdded:
+  if onAdded =? self.onAdded:
     try:
-      await onReservationAdded(availability)
+      await onAdded(availability)
     except CatchableError as e:
       # we don't have any insight into types of errors that `onProcessSlot` can
       # throw because it is caller-defined
-      warn "Unknown error during 'onReservationAdded' callback",
+      warn "Unknown error during 'onAdded' callback",
         availabilityId = availability.id, error = e.msg
 
   return success()
@@ -292,6 +299,13 @@ proc markUnused*(
   let r = await self.update(availability)
   if r.isOk:
     trace "availability marked unused", id = id.toArray.toHex
+
+    if onMarkedUnused =? self.onMarkUnused:
+      try:
+        await onMarkedUnused(availability)
+      except CatchableError as e:
+        warn "Unknown error during 'onMarkedUnused' callback",
+          availabilityId = availability.id, error = e.msg
   return r
 
 iterator items*(self: AvailabilityIter): Future[?Availability] =
diff --git a/tests/codex/sales/testreservations.nim b/tests/codex/sales/testreservations.nim
index db02d46d..4d177fbf 100644
--- a/tests/codex/sales/testreservations.nim
+++ b/tests/codex/sales/testreservations.nim
@@ -117,6 +117,25 @@ asyncchecksuite "Reservations module":
 
     check not available.used
 
+  test "onMarkedUnused called when availability marked unused":
+    var markedUnused: Availability
+    reservations.onMarkUnused = proc(a: Availability) {.async.} =
+      markedUnused = a
+
+    check isOk await reservations.reserve(availability)
+    check isOk await reservations.markUnused(availability.id)
+
+    check markedUnused == availability
+
+  test "onAdded called when availability is reserved":
+    var added: Availability
+    reservations.onAdded = proc(a: Availability) {.async.} =
+      added = a
+
+    check isOk await reservations.reserve(availability)
+
+    check added == availability
+
   test "used availability can be found":
     check isOk await reservations.reserve(availability)