diff --git a/codex/erasure/erasure.nim b/codex/erasure/erasure.nim
index 56e3e1cf..7cab5d42 100644
--- a/codex/erasure/erasure.nim
+++ b/codex/erasure/erasure.nim
@@ -322,7 +322,7 @@ proc encodeData(
           return failure("Unable to store block!")
         idx.inc(params.steps)
 
-    without tree =? CodexTree.init(cids[]), err:
+    without tree =? (await CodexTree.init(cids[])), err:
       return failure(err)
 
     without treeCid =? tree.rootCid, err:
@@ -441,7 +441,7 @@ proc decode*(
   finally:
     decoder.release()
 
-  without tree =? CodexTree.init(cids[0..<encoded.originalBlocksCount]), err:
+  without tree =? (await CodexTree.init(cids[0..<encoded.originalBlocksCount])), err:
     return failure(err)
 
   without treeCid =? tree.rootCid, err:
diff --git a/codex/merkletree/codex/codex.nim b/codex/merkletree/codex/codex.nim
index 974123f2..4855ed07 100644
--- a/codex/merkletree/codex/codex.nim
+++ b/codex/merkletree/codex/codex.nim
@@ -145,16 +145,18 @@ func compress*(
   mhash.coder(@x & @y & @[ key.byte ], digest)
   success digest
 
-func init*(
+proc init*(
   _: type CodexTree,
   mcodec: MultiCodec = Sha256HashCodec,
-  leaves: openArray[ByteHash]): ?!CodexTree =
+  leaves: seq[ByteHash]): Future[?!CodexTree] {.async.} =
 
   if leaves.len == 0:
     return failure "Empty leaves"
 
+  without mhash =? mcodec.mhash(), error:
+    return failure error
+
   let
-    mhash = ? mcodec.mhash()
     compressor = proc(x, y: seq[byte], key: ByteTreeKey): ?!ByteHash {.noSideEffect.} =
       compress(x, y, key, mhash)
     Zero: ByteHash = newSeq[byte](mhash.size)
@@ -165,33 +167,42 @@ func init*(
   var
     self = CodexTree(mcodec: mcodec, compress: compressor, zero: Zero)
 
-  self.layers = ? merkleTreeWorker(self, leaves, isBottomLayer = true)
+  without layers =? (await merkleTreeWorker(self, leaves, isBottomLayer = true)), error:
+    return failure error
+
+  self.layers = layers
   success self
 
-func init*(
+proc init*(
   _: type CodexTree,
-  leaves: openArray[MultiHash]): ?!CodexTree =
+  leaves: seq[MultiHash]): Future[?!CodexTree] {.async.} =
 
   if leaves.len == 0:
     return failure "Empty leaves"
 
   let
     mcodec = leaves[0].mcodec
-    leaves = leaves.mapIt( it.digestBytes )
+    leafBytes = leaves.mapIt( it.digestBytes )
 
-  CodexTree.init(mcodec, leaves)
+  await CodexTree.init(mcodec, leafBytes)
 
-func init*(
+proc init*(
   _: type CodexTree,
-  leaves: openArray[Cid]): ?!CodexTree =
+  leaves: seq[Cid]): Future[?!CodexTree] {.async.} =
+
   if leaves.len == 0:
     return failure "Empty leaves"
 
-  let
-    mcodec = (? leaves[0].mhash.mapFailure).mcodec
-    leaves = leaves.mapIt( (? it.mhash.mapFailure).digestBytes )
+  without mhash =? leaves[0].mhash.mapFailure, error:
+    return failure error
 
-  CodexTree.init(mcodec, leaves)
+  var hashes = newSeq[seq[byte]]()
+  for leaf in leaves:
+    without hash =? leaf.mhash.mapFailure, error:
+      return failure error
+    hashes.add(hash.digestBytes)
+
+  await CodexTree.init(mhash.mcodec, hashes)
 
 proc fromNodes*(
   _: type CodexTree,
diff --git a/codex/merkletree/merkletree.nim b/codex/merkletree/merkletree.nim
index 2f46b93d..1173bcc0 100644
--- a/codex/merkletree/merkletree.nim
+++ b/codex/merkletree/merkletree.nim
@@ -11,6 +11,7 @@
 
 import std/bitops
 
+import pkg/chronos
 import pkg/questionable/results
 
 import ../errors
@@ -120,10 +121,11 @@ func reconstructRoot*[H, K](proof: MerkleProof[H, K], leaf: H): ?!H =
 func verify*[H, K](proof: MerkleProof[H, K], leaf: H, root: H): ?!bool =
   success bool(root == ? proof.reconstructRoot(leaf))
 
-func merkleTreeWorker*[H, K](
+# TODO: replace with implementation in poseidon library plz
+proc merkleTreeWorker*[H, K](
   self: MerkleTree[H, K],
-  xs: openArray[H],
-  isBottomLayer: static bool): ?!seq[seq[H]] =
+  xs: seq[H],
+  isBottomLayer: static bool): Future[?!seq[seq[H]]] {.async.} =
 
   let a = low(xs)
   let b = high(xs)
@@ -145,9 +147,17 @@ func merkleTreeWorker*[H, K](
 
   for i in 0..<halfn:
     const key = when isBottomLayer: K.KeyBottomLayer else: K.KeyNone
-    ys[i] = ? self.compress( xs[a + 2 * i], xs[a + 2 * i + 1], key = key )
+    without y =? self.compress( xs[a + 2 * i], xs[a + 2 * i + 1], key = key ), err:
+      return failure err
+    ys[i] = y
+    # yield?
+    await sleepAsync(1.millis) # cooperative scheduling (may not be necessary)
   if isOdd:
     const key = when isBottomLayer: K.KeyOddAndBottomLayer else: K.KeyOdd
-    ys[halfn] = ? self.compress( xs[n], self.zero, key = key )
+    without y =? self.compress( xs[n], self.zero, key = key ), err:
+      return failure err
+    ys[halfn] = y
 
-  success @[ @xs ] & ? self.merkleTreeWorker(ys, isBottomLayer = false)
+  without v =? (await self.merkleTreeWorker(ys, isBottomLayer = false)), err:
+    return failure err
+  success @[ @xs ] & v
diff --git a/codex/merkletree/poseidon2.nim b/codex/merkletree/poseidon2.nim
index 2e56a4b9..bcbe98eb 100644
--- a/codex/merkletree/poseidon2.nim
+++ b/codex/merkletree/poseidon2.nim
@@ -11,6 +11,7 @@
 
 import std/sequtils
 
+import pkg/chronos
 import pkg/poseidon2
 import pkg/constantine/math/io/io_fields
 import pkg/constantine/platforms/abstractions
@@ -67,9 +68,9 @@ converter toKey*(key: PoseidonKeysEnum): Poseidon2Hash =
   of KeyOdd: KeyOddF
   of KeyOddAndBottomLayer: KeyOddAndBottomLayerF
 
-func init*(
+proc init*(
   _: type Poseidon2Tree,
-  leaves: openArray[Poseidon2Hash]): ?!Poseidon2Tree =
+  leaves: seq[Poseidon2Hash]): Future[?!Poseidon2Tree] {.async.} =
 
   if leaves.len == 0:
     return failure "Empty leaves"
@@ -83,12 +84,14 @@ func init*(
   var
     self = Poseidon2Tree(compress: compressor, zero: Poseidon2Zero)
 
-  self.layers = ? merkleTreeWorker(self, leaves, isBottomLayer = true)
+  without l =? (await merkleTreeWorker(self, leaves, isBottomLayer = true)), err:
+    return failure err
+  self.layers = l
   success self
 
-func init*(
+proc init*(
   _: type Poseidon2Tree,
-  leaves: openArray[array[31, byte]]): ?!Poseidon2Tree =
+  leaves: seq[array[31, byte]]): Future[?!Poseidon2Tree] {.async.} =
   Poseidon2Tree.init(
     leaves.mapIt( Poseidon2Hash.fromBytes(it) ))
 
diff --git a/codex/node.nim b/codex/node.nim
index 956acd49..ebda0359 100644
--- a/codex/node.nim
+++ b/codex/node.nim
@@ -339,7 +339,7 @@ proc store*(
   finally:
     await stream.close()
 
-  without tree =? CodexTree.init(cids), err:
+  without tree =? (await CodexTree.init(cids)), err:
     return failure(err)
 
   without treeCid =? tree.rootCid(CIDv1, dataCodec), err:
@@ -446,19 +446,23 @@ proc setupRequest(
       self.taskpool)
 
   without encoded =? (await erasure.encode(manifest, ecK, ecM)), error:
-    trace "Unable to erasure code dataset"
+    error "Unable to erasure code dataset"
     return failure(error)
 
   without builder =? Poseidon2Builder.new(self.networkStore.localStore, encoded), err:
-    trace "Unable to create slot builder"
+    error "Unable to create slot builder"
+    return failure(err)
+
+  if err =? (await builder.init()).errorOption:
+    error "Failed to initialize slot builder"
     return failure(err)
 
   without verifiable =? (await builder.buildManifest()), err:
-    trace "Unable to build verifiable manifest"
+    error "Unable to build verifiable manifest"
     return failure(err)
 
   without manifestBlk =? await self.storeManifest(verifiable), err:
-    trace "Unable to store verifiable manifest"
+    error "Unable to store verifiable manifest"
     return failure(err)
 
   let
@@ -550,17 +554,21 @@ proc onStore(
   trace "Received a request to store a slot"
 
   without cid =? Cid.init(request.content.cid).mapFailure, err:
-    trace "Unable to parse Cid", cid
+    error "Unable to parse Cid", cid
     return failure(err)
 
   without manifest =? (await self.fetchManifest(cid)), err:
-    trace "Unable to fetch manifest for cid", cid, err = err.msg
+    error "Unable to fetch manifest for cid", cid, err = err.msg
     return failure(err)
 
   without builder =? Poseidon2Builder.new(
     self.networkStore, manifest, manifest.verifiableStrategy
   ), err:
-    trace "Unable to create slots builder", err = err.msg
+    error "Unable to create slots builder", err = err.msg
+    return failure(err)
+
+  if err =? (await builder.init()).errorOption:
+    error "Failed to initialize slot builder"
     return failure(err)
 
   let
diff --git a/codex/slots/builder/builder.nim b/codex/slots/builder/builder.nim
index f999a514..8f9ec97a 100644
--- a/codex/slots/builder/builder.nim
+++ b/codex/slots/builder/builder.nim
@@ -161,8 +161,7 @@ proc buildBlockTree*[T, H](
   if blk.isEmpty:
     success (self.emptyBlock, self.emptyDigestTree)
   else:
-    without tree =?
-      T.digestTree(blk.data, self.cellSize.int), err:
+    without tree =? (await T.digestTree(blk.data, self.cellSize.int)), err:
       error "Failed to create digest for block", err = err.msg
       return failure(err)
 
@@ -213,7 +212,7 @@ proc buildSlotTree*[T, H](
     error "Failed to select slot blocks", err = err.msg
     return failure(err)
 
-  T.init(cellHashes)
+  await T.init(cellHashes)
 
 proc buildSlot*[T, H](
   self: SlotsBuilder[T, H],
@@ -251,8 +250,8 @@ proc buildSlot*[T, H](
 
   tree.root()
 
-func buildVerifyTree*[T, H](self: SlotsBuilder[T, H], slotRoots: openArray[H]): ?!T =
-  T.init(@slotRoots)
+proc buildVerifyTree*[T, H](self: SlotsBuilder[T, H], slotRoots: seq[H]): Future[?!T] {.async.} =
+  await T.init(@slotRoots)
 
 proc buildSlots*[T, H](self: SlotsBuilder[T, H]): Future[?!void] {.async.} =
   ## Build all slot trees and store them in the block store.
@@ -272,7 +271,7 @@ proc buildSlots*[T, H](self: SlotsBuilder[T, H]): Future[?!void] {.async.} =
           return failure(err)
         slotRoot
 
-  without tree =? self.buildVerifyTree(self.slotRoots) and root =? tree.root, err:
+  without tree =? (await self.buildVerifyTree(self.slotRoots)) and root =? tree.root, err:
     error "Failed to build slot roots tree", err = err.msg
     return failure(err)
 
@@ -305,6 +304,28 @@ proc buildManifest*[T, H](self: SlotsBuilder[T, H]): Future[?!Manifest] {.async.
     self.cellSize,
     self.strategy.strategyType)
 
+proc init*[T, H](self: SlotsBuilder[T, H]): Future[?!void] {.async.} =
+  without emptyTree =? (await T.digestTree(self.emptyBlock, self.cellSize.int)), err:
+    return failure err
+  self.emptyDigestTree = emptyTree
+
+  if self.manifest.verifiable:
+    without tree =? (await self.buildVerifyTree(self.slotRoots)), err:
+      return failure err
+
+    without verifyRoot =? tree.root, err:
+      return failure err
+
+    without expectedRoot =? self.manifest.verifyRoot.fromVerifyCid(), err:
+      return failure err
+
+    if verifyRoot != expectedRoot:
+      return failure "Existing slots root doesn't match reconstructed root."
+
+    self.verifiableTree = some tree
+
+  trace "Slots builder initialized"
+
 proc new*[T, H](
   _: type SlotsBuilder[T, H],
   store: BlockStore,
@@ -346,7 +367,7 @@ proc new*[T, H](
     numBlocksTotal      = numSlotBlocksTotal * manifest.numSlots          # number of blocks per slot
 
     emptyBlock          = newSeq[byte](manifest.blockSize.int)
-    emptyDigestTree     = ? T.digestTree(emptyBlock, cellSize.int)
+    # emptyDigestTree     = ? (waitFor T.digestTree(emptyBlock, cellSize.int))
 
     strategy = ? strategy.init(
       0,
@@ -372,24 +393,13 @@ proc new*[T, H](
       strategy: strategy,
       cellSize: cellSize,
       emptyBlock: emptyBlock,
-      numSlotBlocks: numSlotBlocksTotal,
-      emptyDigestTree: emptyDigestTree)
+      numSlotBlocks: numSlotBlocksTotal)
 
   if manifest.verifiable:
     if manifest.slotRoots.len == 0 or
       manifest.slotRoots.len != manifest.numSlots:
       return failure "Manifest is verifiable but slot roots are missing or invalid."
 
-    let
-      slotRoots = manifest.slotRoots.mapIt( (? it.fromSlotCid() ))
-      tree = ? self.buildVerifyTree(slotRoots)
-      expectedRoot = ? manifest.verifyRoot.fromVerifyCid()
-      verifyRoot = ? tree.root
-
-    if verifyRoot != expectedRoot:
-      return failure "Existing slots root doesn't match reconstructed root."
-
-    self.slotRoots = slotRoots
-    self.verifiableTree = some tree
+    self.slotRoots = self.manifest.slotRoots.mapIt( (? it.fromSlotCid() ))
 
   success self
diff --git a/codex/utils/poseidon2digest.nim b/codex/utils/poseidon2digest.nim
index efdb3c6a..2f251ab4 100644
--- a/codex/utils/poseidon2digest.nim
+++ b/codex/utils/poseidon2digest.nim
@@ -7,6 +7,7 @@
 ## This file may not be copied, modified, or distributed except according to
 ## those terms.
 
+import pkg/chronos
 import pkg/poseidon2
 import pkg/questionable/results
 import pkg/libp2p/multihash
@@ -32,10 +33,11 @@ func spongeDigest*(
 
   success Sponge.digest(bytes, rate)
 
-func digestTree*(
+# TODO: replace with poseidon2 library call plz
+proc digestTree*(
   _: type Poseidon2Tree,
-  bytes: openArray[byte],
-  chunkSize: int): ?!Poseidon2Tree =
+  bytes: seq[byte],
+  chunkSize: int): Future[?!Poseidon2Tree] {.async.} =
   ## Hashes chunks of data with a sponge of rate 2, and combines the
   ## resulting chunk hashes in a merkle root.
   ##
@@ -50,30 +52,34 @@ func digestTree*(
   while index < bytes.len:
     let start = index
     let finish = min(index + chunkSize, bytes.len)
-    let digest = ? Poseidon2Hash.spongeDigest(bytes.toOpenArray(start, finish - 1), 2)
+    without digest =? Poseidon2Hash.spongeDigest(bytes.toOpenArray(start, finish - 1), 2), err:
+      return failure err
     leaves.add(digest)
     index += chunkSize
-  return Poseidon2Tree.init(leaves)
+    await sleepAsync(1.millis) # cooperative scheduling (may not be necessary)
+  return await Poseidon2Tree.init(leaves)
 
-func digest*(
+proc digest*(
   _: type Poseidon2Tree,
-  bytes: openArray[byte],
-  chunkSize: int): ?!Poseidon2Hash =
+  bytes: seq[byte],
+  chunkSize: int): Future[?!Poseidon2Hash] {.async.} =
   ## Hashes chunks of data with a sponge of rate 2, and combines the
   ## resulting chunk hashes in a merkle root.
   ##
+  without tree =? (await Poseidon2Tree.digestTree(bytes, chunkSize)), err:
+    return failure err
 
-  (? Poseidon2Tree.digestTree(bytes, chunkSize)).root
+  tree.root
 
-func digestMhash*(
+proc digestMhash*(
   _: type Poseidon2Tree,
   bytes: openArray[byte],
-  chunkSize: int): ?!MultiHash =
+  chunkSize: int): Future[?!MultiHash] {.async.} =
   ## Hashes chunks of data with a sponge of rate 2 and
   ## returns the multihash of the root
   ##
 
-  let
-    hash = ? Poseidon2Tree.digest(bytes, chunkSize)
+  without hash =? (await Poseidon2Tree.digest(bytes, chunkSize)), err:
+    return failure err
 
   ? MultiHash.init(Pos2Bn128MrklCodec, hash).mapFailure