diff --git a/reference/nim/proof_input/src/json.nim b/reference/nim/proof_input/src/json.nim
index b3c2c2b..9057756 100644
--- a/reference/nim/proof_input/src/json.nim
+++ b/reference/nim/proof_input/src/json.nim
@@ -97,16 +97,16 @@ proc exportProofInput*(fname: string, prfInput: SlotProofInput) =
 
   h.writeLine("{")
   h.writeLine("  \"dataSetRoot\":      " & toQuotedDecimalF(prfInput.dataSetRoot) )
-  h.writeLine("  \"entropy\":          " & toQuotedDecimalF(prfInput.entropy ) )
-  h.writeLine("  \"nCellsPerSlot\":    " & $(prfInput.nCells) )
-  h.writeLine("  \"nSlotsPerDataSet\": " & $(prfInput.nSlots) )
-  h.writeLine("  \"slotIndex\":        " & $(prfInput.slotIndex) )
-  h.writeLine("  \"slotRoot\":         " & toQuotedDecimalF(prfInput.slotRoot) )
-  h.writeLine("  \"slotProof\":")
+  h.writeLine(", \"entropy\":          " & toQuotedDecimalF(prfInput.entropy ) )
+  h.writeLine(", \"nCellsPerSlot\":    " & $(prfInput.nCells) )
+  h.writeLine(", \"nSlotsPerDataSet\": " & $(prfInput.nSlots) )
+  h.writeLine(", \"slotIndex\":        " & $(prfInput.slotIndex) )
+  h.writeLine(", \"slotRoot\":         " & toQuotedDecimalF(prfInput.slotRoot) )
+  h.writeLine(", \"slotProof\":")
   writeSingleMerklePath(h, "    ", prfInput.slotProof )
-  h.writeLine("  \"cellData\":")
+  h.writeLine(", \"cellData\":")
   writeAllCellData(h, collect( newSeq , (for p in prfInput.proofInputs: p.cellData) ))
-  h.writeLine("  \"merklePaths\":")
+  h.writeLine(", \"merklePaths\":")
   writeAllMerklePaths(h, collect( newSeq , (for p in prfInput.proofInputs: p.merkleProof) ))
   h.writeLine("}")