diff --git a/codex/contracts/market.nim b/codex/contracts/market.nim
index c9a231d5..deba47d6 100644
--- a/codex/contracts/market.nim
+++ b/codex/contracts/market.nim
@@ -115,7 +115,9 @@ method fillSlot(market: OnChainMarket,
                 slotIndex: UInt256,
                 proof: seq[byte],
                 collateral: UInt256) {.async.} =
+  trace "approving funds", amount = collateral, slotIndex, requestId
   await market.approveFunds(collateral)
+  trace "filling slot", slotIndex, requestId
   await market.contract.fillSlot(requestId, slotIndex, proof)
 
 method freeSlot*(market: OnChainMarket, slotId: SlotId) {.async.} =
diff --git a/codex/sales/states/filling.nim b/codex/sales/states/filling.nim
index 045b482d..91faad2a 100644
--- a/codex/sales/states/filling.nim
+++ b/codex/sales/states/filling.nim
@@ -37,3 +37,4 @@ method run(state: SaleFilling, machine: Machine): Future[?State] {.async.} =
 
   debug "Filling slot", requestId = $data.requestId, slotIndex
   await market.fillSlot(data.requestId, slotIndex, state.proof, collateral)
+  debug "Waiting for slot filled event...", requestId = $data.requestId, slotIndex