diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+0.1.0 Enzo Haussecker <enzo@dfinity.org> Tue Jul 03 2018
+
+ * Abstract database to type class
+ * Implement radix tree construction via conduit
+ * Clean-up documentation
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,83 @@
+# dfinity-radix-tree: A generic data integrity layer.
+[![Build Status](https://travis-ci.org/dfinity-lab/hs-radix-tree.svg?branch=master)](https://travis-ci.org/dfinity-lab/hs-radix-tree)
+[![Hackage](https://img.shields.io/hackage/v/dfinity-radix-tree.svg)](https://hackage.haskell.org/package/dfinity-radix-tree)
+[![Dependencies](https://img.shields.io/hackage-deps/v/dfinity-radix-tree.svg)](http://packdeps.haskellers.com/feed?needle=dfinity-radix-tree)
+[![License: GPLv3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
+
+## Overview
+This library allows you to construct a [Merkle tree](https://en.wikipedia.org/wiki/Merkle_tree) on top of any underlying key–value database. It works by organizing your key–value pairs into a binary radix tree, which is well suited for storing large dictionaries of fairly random keys, and is optimized for storing keys of the same length.
+
+## Usage
+Define your database as an instance of the `RadixDatabase` type class. An instance for [LevelDB](http://hackage.haskell.org/package/leveldb-haskell) is already provided.
+```haskell
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+
+import Control.Monad.Trans.Resource
+import Database.LevelDB
+import Network.DFINITY.RadixTree
+
+instance MonadResource m => RadixDatabase (FilePath, Options) m DB where
+   create = uncurry open
+   load database = get database defaultReadOptions
+   store database = put database defaultWriteOptions
+```
+Create a `RadixTree` that is parameterized by your database. If you want to make things more explicit, then define some simple type aliases and wrapper functions.
+```haskell
+import Control.Monad.Trans.Resource
+import Data.ByteString
+import Database.LevelDB
+import Network.DFINITY.RadixTree
+
+type MerkleTree = RadixTree DB
+type MerkleRoot = RadixRoot
+
+createMerkleTree
+   :: MonadResource m
+   => FilePath -- Database.
+   -> Maybe MerkleRoot -- State root.
+   -> m MerkleTree
+createMerkleTree path root =
+   createRadixTree bloomSize cacheSize root (path, options)
+   where
+   bloomSize = 262144
+   cacheSize = 2048
+   options = defaultOptions {createIfMissing = True}
+
+insertMerkleTree
+   :: MonadResource m
+   => ByteString -- Key.
+   -> ByteString -- Value.
+   -> MerkleTree -- Tree.
+   -> m MerkleTree
+insertMerkleTree = insertRadixTree
+
+deleteMerkleTree
+   :: MonadResource m
+   => ByteString -- Key.
+   -> MerkleTree -- Tree.
+   -> m MerkleTree
+deleteMerkleTree = deleteRadixTree
+
+merkleizeMerkleTree
+   :: MonadResource m
+   => MerkleTree -- Tree.
+   -> m (MerkleRoot, MerkleTree)
+merkleizeMerkleTree = merkleizeRadixTree
+
+lookupMerkleTree
+   :: MonadResource m
+   => ByteString -- Key.
+   -> MerkleTree -- Tree.
+   -> m (Maybe (ByteString, MerkleTree))
+lookupMerkleTree = lookupMerkleizedRadixTree
+```
+Using the API above, we can perform operations on the tree as a proxy for the database and see that its contents is uniquely defined by its `MerkleRoot`.
+
+## Contribute
+
+Feel free to join in. All are welcome. Open an [issue](https://github.com/dfinity-lab/hs-radix-tree/issues)!
+
+## License
+
+GPLv3
diff --git a/benchmark/Main.hs b/benchmark/Main.hs
--- a/benchmark/Main.hs
+++ b/benchmark/Main.hs
@@ -2,59 +2,64 @@
 {-# LANGUAGE RecordWildCards #-}
 
 {-# OPTIONS -Wall #-}
+{-# OPTIONS -fno-cse #-}
 
 module Main where
 
 import Control.Monad (foldM)
 import Control.Monad.IO.Class (MonadIO(..))
-import Control.Monad.Trans.Resource (runResourceT)
-import Crypto.Hash.SHA256 (hash)
-import Data.ByteString.Char8 (ByteString, pack)
+import Control.Monad.Trans.Resource (MonadResource, runResourceT)
+import Crypto.Hash.SHA256 (hashlazy)
+import Data.ByteString.Builder (word32BE, toLazyByteString)
+import Data.ByteString.Char8 (ByteString)
 import Data.Default.Class (Default(..))
+import Data.Word (Word32)
+import Database.LevelDB (DB, Options(..))
 import System.Console.CmdArgs (Data, cmdArgs)
 
 import Network.DFINITY.RadixTree
 
 data Args
    = Args
-   { database :: FilePath
+   { path :: FilePath
    } deriving Data
 
 instance Default Args where
    def = Args "benchmark/benchmarkdb"
 
 step
-   :: MonadIO m
-   => (RadixTree -> ByteString -> m RadixTree)
-   -> RadixTree
-   -> Int
-   -> m RadixTree
-step action tree i =
+   :: MonadResource m
+   => (RadixTree DB -> ByteString -> m (RadixTree DB))
+   -> RadixTree DB
+   -> Word32
+   -> m (RadixTree DB)
+step action tree i = do
+   tree' <- action tree key
    if mod i 1000 == 0
-   then merkleizeRadixTree tree >>= flip action key . snd
-   else action tree key
-   where key = hash $ pack $ show i
+   then snd <$> merkleizeRadixTree tree'
+   else pure tree'
+   where key = hashlazy $ toLazyByteString $ word32BE i
 
 foldInsert
-   :: MonadIO m
-   => RadixTree
-   -> [Int]
-   -> m RadixTree
+   :: MonadResource m
+   => RadixTree DB
+   -> [Word32]
+   -> m (RadixTree DB)
 foldInsert = foldM $ step $ flip $ \ key -> insertRadixTree key key
 
 foldDelete
-   :: MonadIO m
-   => RadixTree
-   -> [Int]
-   -> m RadixTree
+   :: MonadResource m
+   => RadixTree DB
+   -> [Word32]
+   -> m (RadixTree DB)
 foldDelete = foldM $ step $ flip deleteRadixTree
 
 main :: IO ()
 main = do
    Args {..} <- cmdArgs def
    runResourceT $ do
-      tree <- createRadixTree 1048576 6144 database Nothing
-      tree' <- foldInsert tree keys
-      tree'' <- foldDelete tree' keys
+      let options = def {createIfMissing = True}
+      tree <- createRadixTree 262144 2048 Nothing (path, options)
+      tree' <- foldInsert tree [1..100000]
+      tree'' <- foldDelete tree' [1..100000]
       liftIO $ print $ isEmptyRadixTree tree''
-      where keys = [1..1000000]
diff --git a/benchmark/dfinity-radix-tree-benchmarks.svg b/benchmark/dfinity-radix-tree-benchmarks.svg
# file too large to diff: benchmark/dfinity-radix-tree-benchmarks.svg
diff --git a/dfinity-radix-tree.cabal b/dfinity-radix-tree.cabal
--- a/dfinity-radix-tree.cabal
+++ b/dfinity-radix-tree.cabal
@@ -1,19 +1,27 @@
-name:          dfinity-radix-tree
-version:       0.0.0
-synopsis:      A Merkleized key–value data store.
-description:   This library provides a simple data integrity layer for LevelDB.
-homepage:      https://github.com/dfinity-lab/hs-radix-tree
-license:       GPL-3
-license-file:  LICENSE
-author:        Enzo Haussecker <enzo@dfinity.org>
-maintainer:    DFINITY USA Research <team@dfinity.org>
-copyright:     2018 DFINITY Stiftung
-category:      Blockchain, DFINITY, Database
-build-type:    Simple
-cabal-version: >=1.10
+Name:               dfinity-radix-tree
+Version:            0.1.0
+Synopsis:           A generic data integrity layer.
+Description:
+   This library allows you to construct a Merkle tree on top of any underlying
+   key–value database. It works by organizing your key–value pairs into a binary
+   radix tree, which is well suited for storing large dictionaries of fairly
+   random keys, and is optimized for storing keys of the same length.
 
-library
-   build-depends:
+License:            GPL-3
+License-File:       LICENSE
+Category:           Blockchain, DFINITY, Database
+Copyright:          2018 DFINITY Stiftung
+Author:             Enzo Haussecker <enzo@dfinity.org>
+Maintainer:         DFINITY USA Research <team@dfinity.org>
+Homepage:           https://github.com/dfinity-lab/hs-radix-tree
+Bug-Reports:        https://github.com/dfinity-lab/hs-radix-tree/issues
+Tested-With:        GHC==8.4.3, GHC==8.2.2
+Build-Type:         Simple
+Cabal-Version:      >= 1.10
+Extra-Source-Files: CHANGELOG.md README.md
+
+Library
+   Build-Depends:
       BoundedChan,
       base >=4.10 && <5,
       base16-bytestring,
@@ -31,17 +39,17 @@
       resourcet,
       semigroups,
       serialise
-   default-language:
+   Default-Language:
       Haskell2010
-   exposed-modules:
+   Exposed-Modules:
       Network.DFINITY.RadixTree
-   ghc-options:
+   GHC-Options:
       -O2
       -Wall
       -fno-warn-missing-signatures
-   hs-source-dirs:
+   HS-Source-Dirs:
       src
-   other-modules:
+   Other-Modules:
       Network.DFINITY.RadixTree.Bits
       Network.DFINITY.RadixTree.Bloom
       Network.DFINITY.RadixTree.Lenses
@@ -50,8 +58,8 @@
       Network.DFINITY.RadixTree.Types
       Network.DFINITY.RadixTree.Utilities
 
-executable dfinity-radix-tree-unit-tests
-   build-depends:
+Executable dfinity-radix-tree-unit-tests
+   Build-Depends:
       aeson,
       base >=4.10 && <5,
       base16-bytestring,
@@ -59,35 +67,37 @@
       cmdargs,
       data-default-class,
       dfinity-radix-tree,
+      leveldb-haskell,
       resourcet,
       text,
       unordered-containers
-   default-language:
+   Default-Language:
       Haskell2010
-   ghc-options:
+   GHC-Options:
       -O2
       -Wall
-   hs-source-dirs:
+   HS-Source-Dirs:
       test
-   main-is:
+   Main-Is:
       Main.hs
 
-executable dfinity-radix-tree-benchmarks
-   build-depends:
+Executable dfinity-radix-tree-benchmarks
+   Build-Depends:
       base >=4.10 && <5,
       bytestring,
       cmdargs,
       cryptohash-sha256,
       data-default-class,
       dfinity-radix-tree,
+      leveldb-haskell,
       resourcet
-   default-language:
+   Default-Language:
       Haskell2010
-   ghc-options:
+   GHC-Options:
       -O2
       -Wall
       -rtsopts
-   hs-source-dirs:
+   HS-Source-Dirs:
       benchmark
-   main-is:
+   Main-Is:
       Main.hs
diff --git a/src/Network/DFINITY/RadixTree.hs b/src/Network/DFINITY/RadixTree.hs
--- a/src/Network/DFINITY/RadixTree.hs
+++ b/src/Network/DFINITY/RadixTree.hs
@@ -1,8 +1,9 @@
+{-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE RecordWildCards #-}
 
 {-# OPTIONS -Wall #-}
-{-# OPTIONS -fno-warn-incomplete-patterns #-}
+{-# OPTIONS -Werror=incomplete-patterns #-}
 
 -- |
 -- Module     : Network.DFINITY.RadixTree
@@ -11,11 +12,14 @@
 -- Maintainer : Enzo Haussecker <enzo@dfinity.org>
 -- Stability  : Stable
 --
--- A Merkleized key–value data store.
+-- A generic data integrity layer.
 module Network.DFINITY.RadixTree (
 
+   -- ** Class
+     RadixDatabase(..)
+
    -- ** Types
-     RadixRoot
+   , RadixRoot
    , RadixTree
    , RadixError(..)
 
@@ -42,6 +46,7 @@
 
    -- ** Stream
    , sourceMerkleizedRadixTree
+   , sinkMerkleizedRadixTree
 
    -- ** Debug
    , printMerkleizedRadixTree
@@ -49,27 +54,29 @@
 
    ) where
 
-import Codec.Serialise (deserialise)
+import Codec.Serialise (deserialise, deserialiseOrFail)
 import Control.Concurrent (forkIO, killThread)
-import Control.Concurrent.BoundedChan (BoundedChan, readChan)
+import Control.Concurrent.BoundedChan (BoundedChan, readChan, tryWriteChan)
 import Control.Concurrent.MVar (modifyMVar_, newMVar, readMVar)
 import Control.Exception (throw)
-import Control.Monad (forM_, forever, when)
+import Control.Monad (foldM, forM_, forever, void, when)
 import Control.Monad.IO.Class (MonadIO(..))
 import Control.Monad.Trans.Resource (MonadResource, ResourceT, allocate, release)
+import Crypto.Hash.SHA256 (hash)
 import Data.BloomFilter as Bloom (elem, insert, insertList)
 import Data.Bool (bool)
-import Data.ByteString.Char8 (ByteString)
+import Data.ByteString.Char8 as Byte (ByteString, take)
 import Data.ByteString.Lazy (fromStrict)
-import Data.ByteString.Short (fromShort)
-import Data.Conduit (Source, yield)
+import Data.ByteString.Short (fromShort, toShort)
+import Data.Conduit (ConduitM, await, yield)
 import Data.Default.Class (def)
+import Data.List as List (delete, foldl', null)
 import Data.List.NonEmpty (NonEmpty(..), fromList)
 import Data.LruCache as LRU (empty, insert, lookup)
-import Data.Map.Strict as Map (empty)
+import Data.Map.Strict as Map ((!), delete, empty, insert, keys, lookup, member, null, singleton)
 import Data.Maybe (fromJust, isJust, isNothing, listToMaybe)
 import Data.Tuple (swap)
-import Database.LevelDB (Options(..), defaultReadOptions, get, open)
+import Database.LevelDB (DB, Options)
 
 import Network.DFINITY.RadixTree.Bits
 import Network.DFINITY.RadixTree.Bloom
@@ -81,23 +88,23 @@
 -- |
 -- Create a radix tree.
 createRadixTree
-   :: MonadResource m
+   :: RadixDatabase config m database
    => Int -- ^ Bloom filter size in bits.
    -> Int -- ^ LRU cache size in items.
-   -> FilePath -- ^ LevelDB database.
-   -> Maybe RadixRoot -- ^ Last valid state root.
-   -> m RadixTree
+   -> Maybe RadixRoot -- ^ Previous state root.
+   -> config -- ^ Database configuration.
+   -> m (RadixTree database)
 {-# SPECIALISE createRadixTree
    :: Int
    -> Int
-   -> FilePath
    -> Maybe RadixRoot
-   -> ResourceT IO RadixTree #-}
-createRadixTree bloomSize cacheSize file checkpoint
+   -> (FilePath, Options)
+   -> ResourceT IO (RadixTree DB) #-}
+createRadixTree bloomSize cacheSize checkpoint config
    | bloomSize <= 0 = throw $ InvalidArgument "invalid Bloom filter size"
    | cacheSize <= 0 = throw $ InvalidArgument "invalid LRU cache size"
    | otherwise = do
-      database <- open file $ def {createIfMissing = True}
+      database <- create config
       (root, cache') <-
          case checkpoint of
             Nothing -> storeCold def cache database
@@ -112,16 +119,16 @@
       cache = LRU.empty cacheSize
 
 -- |
--- Create a radix subtree from a radix tree.
+-- Create a radix tree from a radix tree.
 subtreeRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => RadixRoot -- ^ State root.
-   -> RadixTree -- ^ Radix tree.
-   -> m RadixTree
+   -> RadixTree database -- ^ Radix tree.
+   -> m (RadixTree database)
 {-# SPECIALISE subtreeRadixTree
    :: RadixRoot
-   -> RadixTree
-   -> ResourceT IO RadixTree #-}
+   -> RadixTree DB
+   -> ResourceT IO (RadixTree DB) #-}
 subtreeRadixTree root RadixTree {..} = do
    result <- loadCold root cache _radixDatabase
    case result of
@@ -134,49 +141,49 @@
 -- |
 -- Check if a radix tree is empty.
 isEmptyRadixTree
-   :: RadixTree -- ^ Radix tree.
+   :: RadixTree database -- ^ Radix tree.
    -> Bool
-{-# INLINE isEmptyRadixTree #-}
+{-# INLINABLE isEmptyRadixTree #-}
 isEmptyRadixTree = (==) defaultRoot . _radixRoot
 
 -- |
 -- Check if a state root is valid.
 isValidRadixRoot
-   :: MonadIO m
+   :: RadixDatabase config m database
    => RadixRoot -- ^ State root.
-   -> RadixTree -- ^ Radix tree.
+   -> RadixTree database -- ^ Radix tree.
    -> m Bool
 {-# SPECIALISE isValidRadixRoot
    :: RadixRoot
-   -> RadixTree
+   -> RadixTree DB
    -> ResourceT IO Bool #-}
 isValidRadixRoot root RadixTree {..} =
-   isJust <$> get _radixDatabase defaultReadOptions key
+   isJust <$> load _radixDatabase key
    where
    key = fromShort root
 
 -- |
 -- Search for a value in a radix tree.
 searchRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => Bool -- ^ Overwrite state root?
-   -> (RadixTree -> m (Maybe (RadixBranch, RadixCache))) -- ^ Loading strategy.
+   -> (RadixTree database -> m (Maybe (RadixBranch, RadixCache))) -- ^ Loading strategy.
    -> ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
+   -> RadixTree database -- ^ Radix tree.
    -> m (Either RadixError RadixSearchResult)
 {-# SPECIALISE searchRadixTree
    :: Bool
-   -> (RadixTree -> ResourceT IO (Maybe (RadixBranch, RadixCache)))
+   -> (RadixTree DB -> ResourceT IO (Maybe (RadixBranch, RadixCache)))
    -> ByteString
-   -> RadixTree
+   -> RadixTree DB
    -> ResourceT IO (Either RadixError RadixSearchResult) #-}
-searchRadixTree flag load = \ key tree@RadixTree {..} -> do
+searchRadixTree flag strategy = \ key tree@RadixTree {..} -> do
    let key' = toBits key
    let tree' = tree `bool` setRoot _radixCheckpoint tree $ flag
    loop Nothing [] [] [] key' tree' where
    loop implicit branches roots prefixes key tree@RadixTree {..} = do
       -- Load the root branch.
-      result <- load tree
+      result <- strategy tree
       case result of
          Nothing -> pure $ Left $ StateRootDoesNotExist _radixRoot
          Just (branch@RadixBranch {..}, cache') -> do
@@ -191,10 +198,10 @@
             let prefixes' = prefix:prefixes
             let key' = drop n key
             -- Check the termination criteria.
-            let residue = not $ null overflow
+            let residue = not $ List.null overflow
             let bit = head key'
             let child = bool _radixLeft _radixRight bit
-            if null key' || residue || isNothing child
+            if List.null key' || residue || isNothing child
             then pure $ Right (fromList roots', fromList branches', fromList prefixes', overflow, key', cache')
             else do
                -- Recurse.
@@ -206,13 +213,13 @@
 -- |
 -- Search for a value in a Merkleized radix tree.
 searchMerkleizedRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
+   -> RadixTree database -- ^ Radix tree.
    -> m (Either RadixError RadixSearchResult)
 {-# SPECIALISE searchMerkleizedRadixTree
    :: ByteString
-   -> RadixTree
+   -> RadixTree DB
    -> ResourceT IO (Either RadixError RadixSearchResult) #-}
 searchMerkleizedRadixTree =
    searchRadixTree True $ \ RadixTree {..} ->
@@ -221,13 +228,13 @@
 -- |
 -- Search for a value in a non-Merkleized radix tree.
 searchNonMerkleizedRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
+   -> RadixTree database -- ^ Radix tree.
    -> m (Either RadixError RadixSearchResult)
 {-# SPECIALISE searchNonMerkleizedRadixTree
    :: ByteString
-   -> RadixTree
+   -> RadixTree DB
    -> ResourceT IO (Either RadixError RadixSearchResult) #-}
 searchNonMerkleizedRadixTree =
    searchRadixTree False $ \ RadixTree {..} ->
@@ -236,16 +243,16 @@
 -- |
 -- Insert a key and value into a radix tree.
 insertRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => ByteString -- ^ Key.
    -> ByteString -- ^ Value.
-   -> RadixTree -- ^ Radix tree.
-   -> m RadixTree
+   -> RadixTree database -- ^ Radix tree.
+   -> m (RadixTree database)
 {-# SPECIALISE insertRadixTree
    :: ByteString
    -> ByteString
-   -> RadixTree
-   -> ResourceT IO RadixTree #-}
+   -> RadixTree DB
+   -> ResourceT IO (RadixTree DB) #-}
 insertRadixTree key value tree =
    if isEmptyRadixTree tree
    then pure $ initializeRadixTree key value tree
@@ -264,9 +271,9 @@
 initializeRadixTree
    :: ByteString -- ^ Key.
    -> ByteString -- ^ Value.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE initializeRadixTree #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE initializeRadixTree #-}
 initializeRadixTree key value tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setRoot root tree
    where
@@ -280,9 +287,9 @@
 insertRadixTreeAt
    :: RadixSearchResult -- ^ Search result.
    -> ByteString -- ^ Value.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE insertRadixTreeAt #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE insertRadixTreeAt #-}
 insertRadixTreeAt (_:|roots, branch:|branches, prefix:|_, _, _, cache) value tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -297,9 +304,9 @@
 insertRadixTreeAfter
    :: RadixSearchResult -- ^ Search result.
    -> ByteString -- ^ Value.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE insertRadixTreeAfter #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE insertRadixTreeAfter #-}
 insertRadixTreeAfter (_:|roots, branch:|branches, prefix:|_, _, keyOverflow, cache) value tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -318,9 +325,9 @@
 insertRadixTreeBefore
    :: RadixSearchResult -- ^ Search result.
    -> ByteString -- ^ Value.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE insertRadixTreeBefore #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE insertRadixTreeBefore #-}
 insertRadixTreeBefore (_:|roots, branch:|branches, prefix:|_, prefixOverflow, _, cache) value tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -340,9 +347,9 @@
 insertRadixTreeBetween
    :: RadixSearchResult -- ^ Search result.
    -> ByteString -- ^ Value.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE insertRadixTreeBetween #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE insertRadixTreeBetween #-}
 insertRadixTreeBetween (_:|roots, branch:|branches, prefix:|_, prefixOverflow, keyOverflow, cache) value tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -365,14 +372,14 @@
 -- |
 -- Delete a value from a radix tree.
 deleteRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
-   -> m RadixTree
+   -> RadixTree database -- ^ Radix tree.
+   -> m (RadixTree database)
 {-# SPECIALISE deleteRadixTree
    :: ByteString
-   -> RadixTree
-   -> ResourceT IO RadixTree #-}
+   -> RadixTree DB
+   -> ResourceT IO (RadixTree DB) #-}
 deleteRadixTree key tree@RadixTree {..} =
    if isEmptyRadixTree tree
    then pure tree
@@ -417,9 +424,9 @@
 -- TODO (enzo): Documentation.
 deleteRadixTreeNoChildrenNoParent
    :: RadixSearchResult -- ^ Search result.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE deleteRadixTreeNoChildrenNoParent #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE deleteRadixTreeNoChildrenNoParent #-}
 deleteRadixTreeNoChildrenNoParent (_, _, _, _, _, cache) tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -430,9 +437,9 @@
 -- TODO (enzo): Documentation.
 deleteRadixTreeNoChildrenParentWithLeaf
    :: RadixSearchResult -- ^ Search result.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE deleteRadixTreeNoChildrenParentWithLeaf #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE deleteRadixTreeNoChildrenParentWithLeaf #-}
 deleteRadixTreeNoChildrenParentWithLeaf (_:|_:roots, _:|branch:branches, prefix:|prefixes, _, _, cache) tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -443,6 +450,8 @@
    bloom = flip insertList _radixBloom $ root':roots
    buffer = merkleSpoof root' parent $ storeHot root' branch' _radixBuffer
    state = bool _radixRoot root' $ isNothing parent
+deleteRadixTreeNoChildrenParentWithLeaf _ _ =
+   throw $ InvalidArgument "unknown parent"
 
 -- TODO (enzo): Documentation.
 deleteRadixTreeNoChildrenParentWithoutLeaf
@@ -450,9 +459,9 @@
    -> RadixBranch -- ^ Branch.
    -> RadixCache -- ^ Cache.
    -> Bool -- ^ Lineage.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE deleteRadixTreeNoChildrenParentWithoutLeaf #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE deleteRadixTreeNoChildrenParentWithoutLeaf #-}
 deleteRadixTreeNoChildrenParentWithoutLeaf (_:|_:roots, _:|_:branches, _:|prefixes, _, _, _) branch@RadixBranch {..} cache test tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -464,6 +473,8 @@
    bloom = flip insertList _radixBloom $ root':roots
    buffer = merkleSpoof root' parent $ storeHot root' branch' _radixBuffer
    state = bool _radixRoot root' $ isNothing parent
+deleteRadixTreeNoChildrenParentWithoutLeaf _ _ _ _ _ =
+   throw $ InvalidArgument "unknown parent"
 
 -- TODO (enzo): Documentation.
 deleteRadixTreeOneChild
@@ -471,9 +482,9 @@
    -> RadixBranch -- ^ Branch.
    -> RadixCache -- ^ Cache.
    -> Bool -- ^ Lineage.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE deleteRadixTreeOneChild #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE deleteRadixTreeOneChild #-}
 deleteRadixTreeOneChild (_:|roots, _:|branches, prefix:|_, _, _, _) branch@RadixBranch {..} cache test tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -483,15 +494,15 @@
    bits = prefix ++ test:maybe [] toBits _radixPrefix
    parent = listToMaybe $ zip3 roots branches prefix
    bloom = flip insertList _radixBloom $ root':roots
-   buffer =  merkleSpoof root' parent $ storeHot root' branch' _radixBuffer
+   buffer = merkleSpoof root' parent $ storeHot root' branch' _radixBuffer
    state = bool _radixRoot root' $ isNothing parent
 
 -- TODO (enzo): Documentation.
 deleteRadixTreeTwoChildren
    :: RadixSearchResult -- ^ Search result.
-   -> RadixTree -- ^ Radix tree.
-   -> RadixTree
-{-# INLINE deleteRadixTreeTwoChildren #-}
+   -> RadixTree database -- ^ Radix tree.
+   -> RadixTree database
+{-# INLINABLE deleteRadixTreeTwoChildren #-}
 deleteRadixTreeTwoChildren (_:|roots, branch:|branches, prefix:|_, _, _, cache) tree@RadixTree {..} =
    seq bloom $ setBloom bloom $ setBuffer buffer $ setCache cache $ setRoot state tree
    where
@@ -505,22 +516,22 @@
 -- |
 -- Lookup a value in a radix tree.
 lookupRadixTree
-   :: MonadIO m
-   => (ByteString -> RadixTree -> m (Either RadixError RadixSearchResult)) -- ^ Search algorithm.
+   :: RadixDatabase config m database
+   => (ByteString -> RadixTree database -> m (Either RadixError RadixSearchResult)) -- ^ Search algorithm.
    -> ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
-   -> m (Maybe (ByteString, RadixTree))
+   -> RadixTree database -- ^ Radix tree.
+   -> m (Maybe (ByteString, RadixTree database))
 {-# SPECIALISE lookupRadixTree
-   :: (ByteString -> RadixTree -> ResourceT IO (Either RadixError RadixSearchResult))
+   :: (ByteString -> RadixTree DB -> ResourceT IO (Either RadixError RadixSearchResult))
    -> ByteString
-   -> RadixTree
-   -> ResourceT IO (Maybe (ByteString, RadixTree)) #-}
+   -> RadixTree DB
+   -> ResourceT IO (Maybe (ByteString, RadixTree DB)) #-}
 lookupRadixTree search key tree = do
    found <- search key tree
    case found of
       Left err -> throw err
       Right (_, RadixBranch {..}:|_, _, prefixOverflow, keyOverflow, cache') ->
-         if not $ null prefixOverflow && null keyOverflow
+         if not $ List.null prefixOverflow && List.null keyOverflow
          then pure Nothing
          else pure $ do
             value <- _radixLeaf
@@ -530,27 +541,27 @@
 -- |
 -- Lookup a value in a Merkleized radix tree.
 lookupMerkleizedRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
-   -> m (Maybe (ByteString, RadixTree))
+   -> RadixTree database -- ^ Radix tree.
+   -> m (Maybe (ByteString, RadixTree database))
 {-# SPECIALISE lookupMerkleizedRadixTree
    :: ByteString
-   -> RadixTree
-   -> ResourceT IO (Maybe (ByteString, RadixTree)) #-}
+   -> RadixTree DB
+   -> ResourceT IO (Maybe (ByteString, RadixTree DB)) #-}
 lookupMerkleizedRadixTree = lookupRadixTree searchMerkleizedRadixTree
 
 -- |
 -- Lookup a value in a non-Merkleized radix tree.
 lookupNonMerkleizedRadixTree
-   :: MonadIO m
+   :: RadixDatabase config m database
    => ByteString -- ^ Key.
-   -> RadixTree -- ^ Radix tree.
-   -> m (Maybe (ByteString, RadixTree))
+   -> RadixTree database -- ^ Radix tree.
+   -> m (Maybe (ByteString, RadixTree database))
 {-# SPECIALISE lookupNonMerkleizedRadixTree
    :: ByteString
-   -> RadixTree
-   -> ResourceT IO (Maybe (ByteString, RadixTree)) #-}
+   -> RadixTree DB
+   -> ResourceT IO (Maybe (ByteString, RadixTree DB)) #-}
 lookupNonMerkleizedRadixTree = lookupRadixTree searchNonMerkleizedRadixTree
 
 -- |
@@ -560,7 +571,7 @@
    -> Maybe (RadixRoot, RadixBranch, Bool) -- ^ Parent.
    -> RadixBuffer -- ^ Buffer.
    -> RadixBuffer
-{-# INLINE merkleSpoof #-}
+{-# INLINABLE merkleSpoof #-}
 merkleSpoof mask = \ case
    Nothing -> id
    Just (root, branch, test) ->
@@ -569,12 +580,12 @@
 -- |
 -- Merkleize a radix tree. This will flush the buffer to disk.
 merkleizeRadixTree
-   :: MonadIO m
-   => RadixTree -- ^ Radix tree.
-   -> m (RadixRoot, RadixTree)
+   :: RadixDatabase config m database
+   => RadixTree database-- ^ Radix tree.
+   -> m (RadixRoot, RadixTree database)
 {-# SPECIALISE merkleizeRadixTree
-   :: RadixTree
-   -> ResourceT IO (RadixRoot, RadixTree) #-}
+   :: RadixTree DB
+   -> ResourceT IO (RadixRoot, RadixTree DB) #-}
 merkleizeRadixTree RadixTree {..} = do
    (root, cache) <- loop _radixRoot _radixCache
    let tree = RadixTree bloom _radixBloomSize Map.empty cache _radixCacheSize root _radixDatabase root
@@ -615,18 +626,19 @@
 -- Create a conduit from a Merkleized radix tree.
 sourceMerkleizedRadixTree
    :: MonadResource m
-   => [Bool] -- ^ Bit patten.
+   => RadixDatabase config (ConduitM () ByteString m) database
+   => [Bool] -- ^ Bit mask.
    -> Int -- ^ LRU cache size in items.
    -> BoundedChan RadixRoot -- ^ Terminal state root producer.
-   -> RadixTree -- ^ Radix tree.
-   -> Source m ByteString
+   -> RadixTree database -- ^ Radix tree.
+   -> ConduitM () ByteString m ()
 {-# SPECIALISE sourceMerkleizedRadixTree
    :: [Bool]
    -> Int
    -> BoundedChan RadixRoot
-   -> RadixTree
-   -> Source (ResourceT IO) ByteString #-}
-sourceMerkleizedRadixTree patten cacheSize chan
+   -> RadixTree DB
+   -> ConduitM () ByteString (ResourceT IO) () #-}
+sourceMerkleizedRadixTree mask cacheSize chan
    | cacheSize <= 0 = throw $ InvalidArgument "invalid LRU cache size"
    | otherwise = \ tree -> do
       cache <- liftIO $ newMVar $ LRU.empty cacheSize
@@ -643,35 +655,110 @@
          then pure ()
          else do
             let key = fromShort _radixCheckpoint
-            result <- get _radixDatabase defaultReadOptions key
+            result <- load _radixDatabase key
             case result of
                Nothing -> pure ()
                Just bytes -> do
                   let RadixBranch {..} = deserialise $ fromStrict bytes
-                  let success = all id $ zipWith (==) patten $ toBits $ fromShort _radixCheckpoint
+                  let success = all id $ zipWith (==) mask $ toBits $ fromShort _radixCheckpoint
                   when success $ yield bytes
                   forM_ [_radixLeft, _radixRight] $ \ case
                      Nothing -> pure ()
                      Just root -> loop cache `flip` roots' $ setCheckpoint root tree
 
 -- |
+-- Create a Merkleized radix tree from a conduit.
+sinkMerkleizedRadixTree
+   :: MonadResource m
+   => RadixDatabase config (ConduitM ByteString () m) database
+   => RadixRoot -- ^ Target state root.
+   -> BoundedChan RadixRoot -- ^ Terminal state root consumer.
+   -> RadixTree database -- ^ Radix tree.
+   -> ConduitM ByteString () m (Either [RadixRoot] (RadixTree database))
+{-# SPECIALISE sinkMerkleizedRadixTree
+   :: RadixRoot
+   -> BoundedChan RadixRoot
+   -> RadixTree DB
+   -> ConduitM ByteString () (ResourceT IO) (Either [RadixRoot] (RadixTree DB)) #-}
+sinkMerkleizedRadixTree checkpoint chan tree@RadixTree {..} =
+   loop1 Map.empty $ singleton checkpoint Nothing where
+   loop1 = \ buffer want ->
+      if Map.null want
+      then pure $ Right $ setCheckpoint checkpoint $ setRoot checkpoint tree
+      else await >>= \ case
+         Nothing -> pure $ Left $ keys want
+         Just bytes ->
+            case deserialiseOrFail $ fromStrict bytes of
+               Right RadixBranch {..} -> do
+                  let key = Byte.take 20 $ hash bytes
+                  let root = toShort key
+                  let wanted = member root want
+                  exists <- if wanted
+                     then pure False
+                     else isJust <$> load _radixDatabase key
+                  if exists
+                  then loop1 buffer $ Map.delete root want
+                  else do
+                     children <- foldM step [] $ maybe id (:) _radixLeft $ maybe id (:) _radixRight []
+                     let buffer' = Map.insert root (key, bytes, children) buffer
+                     if not wanted
+                     then loop1 buffer' want
+                     else loop3 buffer' `uncurry` loop2 buffer' (want, []) root
+               _ -> loop1 buffer want
+      where
+      step accum root = do
+         valid <- isValidRadixRoot root tree
+         if valid
+         then pure accum
+         else pure $ root:accum
+   loop2 buffer accum@(want, candidates) root =
+      case Map.lookup root buffer of
+         Nothing -> accum
+         Just (key, bytes, []) -> (want, (root, key, bytes):candidates)
+         Just (_, _, children) ->
+            let want' = foldr step want children
+            in foldl' (loop2 buffer) (want', candidates) children
+      where
+      step = flip Map.insert $ Just root
+   loop3 buffer want = \ case
+      [] -> loop1 buffer want
+      (root, key, bytes):candidates -> do
+         store _radixDatabase key bytes
+         let buffer' = Map.delete root buffer
+         case want ! root of
+            Nothing -> do
+               let want' = Map.delete root want
+               loop1 buffer' want'
+            Just root' -> do
+               let want' = Map.delete root want
+               let (key', bytes', siblings') = buffer ! root'
+               let children' = List.delete root siblings'
+               if List.null children'
+               then loop3 buffer' want' $ (root', key', bytes'):candidates
+               else do
+                  let buffer'' = Map.insert root' (key', bytes', children') buffer'
+                  liftIO $ void $ tryWriteChan chan root
+                  loop3 buffer'' want' candidates
+
+-- |
 -- Print a radix tree.
 printRadixTree
    :: MonadIO m
+   => RadixDatabase config m database
    => Bool -- ^ Overwrite state root?
-   -> (RadixTree -> m (Maybe (RadixBranch, RadixCache))) -- ^ Loading strategy.
-   -> RadixTree -- ^ Radix tree.
+   -> (RadixTree database -> m (Maybe (RadixBranch, RadixCache))) -- ^ Loading strategy.
+   -> RadixTree database -- ^ Radix tree.
    -> m ()
 {-# SPECIALISE printRadixTree
    :: Bool
-   -> (RadixTree -> ResourceT IO (Maybe (RadixBranch, RadixCache)))
-   -> RadixTree
+   -> (RadixTree DB -> ResourceT IO (Maybe (RadixBranch, RadixCache)))
+   -> RadixTree DB
    -> ResourceT IO () #-}
-printRadixTree flag load = \ tree@RadixTree {..} -> do
+printRadixTree flag strategy = \ tree@RadixTree {..} -> do
    let tree' = tree `bool` setRoot _radixCheckpoint tree $ flag
    loop tree' 0 where
    loop tree@RadixTree {..} i = do
-      result <- load tree
+      result <- strategy tree
       case fst <$> result of
          Nothing -> throw $ StateRootDoesNotExist _radixRoot
          Just branch@RadixBranch {..} -> do
@@ -686,10 +773,11 @@
 -- Print a Merkleized radix tree.
 printMerkleizedRadixTree
    :: MonadIO m
-   => RadixTree -- ^ Radix tree.
+   => RadixDatabase config m database
+   => RadixTree database -- ^ Radix tree.
    -> m ()
 {-# SPECIALISE printMerkleizedRadixTree
-   :: RadixTree
+   :: RadixTree DB
    -> ResourceT IO () #-}
 printMerkleizedRadixTree =
    printRadixTree True $ \ RadixTree {..} ->
@@ -699,10 +787,11 @@
 -- Print a non-Merkleized radix tree.
 printNonMerkleizedRadixTree
    :: MonadIO m
-   => RadixTree -- ^ Radix tree.
+   => RadixDatabase config m database
+   => RadixTree database -- ^ Radix tree.
    -> m ()
 {-# SPECIALISE printNonMerkleizedRadixTree
-   :: RadixTree
+   :: RadixTree DB
    -> ResourceT IO () #-}
 printNonMerkleizedRadixTree =
    printRadixTree False $ \ RadixTree {..} ->
diff --git a/src/Network/DFINITY/RadixTree/Lenses.hs b/src/Network/DFINITY/RadixTree/Lenses.hs
--- a/src/Network/DFINITY/RadixTree/Lenses.hs
+++ b/src/Network/DFINITY/RadixTree/Lenses.hs
@@ -56,19 +56,19 @@
 getLeaf :: RadixBranch -> Maybe ByteString
 getLeaf = view radixLeaf
 
-getBloom :: RadixTree -> RadixBloom
+getBloom :: RadixTree database -> RadixBloom
 getBloom = view radixBloom
 
-getBuffer :: RadixTree -> RadixBuffer
+getBuffer :: RadixTree database -> RadixBuffer
 getBuffer = view radixBuffer
 
-getCache :: RadixTree -> RadixCache
+getCache :: RadixTree database -> RadixCache
 getCache = view radixCache
 
-getCheckpoint :: RadixTree -> RadixRoot
+getCheckpoint :: RadixTree database -> RadixRoot
 getCheckpoint = view radixCheckpoint
 
-getRoot :: RadixTree -> RadixRoot
+getRoot :: RadixTree database -> RadixRoot
 getRoot = view radixRoot
 
 setPrefix :: Maybe RadixPrefix -> RadixBranch -> RadixBranch
@@ -89,17 +89,17 @@
 setLeaf :: Maybe ByteString -> RadixBranch -> RadixBranch
 setLeaf = set radixLeaf
 
-setBloom :: RadixBloom -> RadixTree -> RadixTree
+setBloom :: RadixBloom -> RadixTree database -> RadixTree database
 setBloom = set radixBloom
 
-setBuffer :: RadixBuffer -> RadixTree -> RadixTree
+setBuffer :: RadixBuffer -> RadixTree database -> RadixTree database
 setBuffer = set radixBuffer
 
-setCache :: RadixCache -> RadixTree -> RadixTree
+setCache :: RadixCache -> RadixTree database -> RadixTree database
 setCache = set radixCache
 
-setCheckpoint :: RadixRoot -> RadixTree -> RadixTree
+setCheckpoint :: RadixRoot -> RadixTree database -> RadixTree database
 setCheckpoint = set radixCheckpoint
 
-setRoot :: RadixRoot -> RadixTree -> RadixTree
+setRoot :: RadixRoot -> RadixTree database -> RadixTree database
 setRoot = set radixRoot
diff --git a/src/Network/DFINITY/RadixTree/Memory.hs b/src/Network/DFINITY/RadixTree/Memory.hs
--- a/src/Network/DFINITY/RadixTree/Memory.hs
+++ b/src/Network/DFINITY/RadixTree/Memory.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE RecordWildCards #-}
-
 {-# OPTIONS -Wall #-}
 
 module Network.DFINITY.RadixTree.Memory
@@ -10,42 +8,53 @@
    ) where
 
 import Codec.Serialise (deserialise, serialise)
-import Control.Monad.IO.Class (MonadIO)
+import Control.Monad.Trans.Resource (ResourceT)
 import Crypto.Hash.SHA256 (hash)
 import Data.ByteString.Char8 as Byte (take)
 import Data.ByteString.Lazy (fromStrict, toStrict)
 import Data.ByteString.Short (fromShort, toShort)
 import Data.LruCache as LRU (insert, lookup)
 import Data.Map.Strict as Map (insert, lookup)
-import Database.LevelDB (defaultReadOptions, defaultWriteOptions, get, put)
+import Database.LevelDB (DB)
 
 import Network.DFINITY.RadixTree.Types
 
 loadHot
-   :: MonadIO m
-   => RadixRoot -- ^ State root.
-   -> RadixBuffer -- ^ Buffer.
-   -> RadixCache -- ^ Cache.
-   -> RadixDatabase -- ^ Database.
+   :: RadixDatabase config m database
+   => RadixRoot
+   -> RadixBuffer
+   -> RadixCache
+   -> database
    -> m (Maybe (RadixBranch, RadixCache))
+{-# SPECIALISE loadHot
+   :: RadixRoot
+   -> RadixBuffer
+   -> RadixCache
+   -> DB
+   -> ResourceT IO (Maybe (RadixBranch, RadixCache)) #-}
 loadHot root buffer cache database =
    case Map.lookup root buffer of
       Just branch -> pure $ Just (branch, cache)
       Nothing -> loadCold root cache database
 
 loadCold
-   :: MonadIO m
-   => RadixRoot -- ^ State root.
-   -> RadixCache -- ^ Cache.
-   -> RadixDatabase -- ^ Database.
+   :: RadixDatabase config m database
+   => RadixRoot
+   -> RadixCache
+   -> database
    -> m (Maybe (RadixBranch, RadixCache))
+{-# SPECIALISE loadCold
+   :: RadixRoot
+   -> RadixCache
+   -> DB
+   -> ResourceT IO (Maybe (RadixBranch, RadixCache)) #-}
 loadCold root cache database =
    case LRU.lookup root cache of
       Just (branch, cache') ->
          seq cache' $ seq branch $ pure $ Just (branch, cache')
       Nothing -> do
          let key = fromShort root
-         result <- get database defaultReadOptions key
+         result <- load database key
          case result of
             Just bytes -> do
                let branch = deserialise $ fromStrict bytes
@@ -54,20 +63,25 @@
             Nothing -> pure $ Nothing
 
 storeHot
-   :: RadixRoot -- ^ State root.
-   -> RadixBranch -- ^ Branch.
-   -> RadixBuffer -- ^ Buffer.
+   :: RadixRoot
+   -> RadixBranch
    -> RadixBuffer
+   -> RadixBuffer
 storeHot = Map.insert
 
 storeCold
-   :: MonadIO m
-   => RadixBranch -- ^ Branch.
-   -> RadixCache -- ^ Cache.
-   -> RadixDatabase -- ^ Database.
+   :: RadixDatabase config m database
+   => RadixBranch
+   -> RadixCache
+   -> database
    -> m (RadixRoot, RadixCache)
+{-# SPECIALISE storeCold
+   :: RadixBranch
+   -> RadixCache
+   -> DB
+   -> ResourceT IO (RadixRoot, RadixCache) #-}
 storeCold branch cache database = do
-   put database defaultWriteOptions key bytes
+   store database key bytes
    seq cache' $ pure (root, cache')
    where
    bytes = toStrict $ serialise branch
diff --git a/src/Network/DFINITY/RadixTree/Types.hs b/src/Network/DFINITY/RadixTree/Types.hs
--- a/src/Network/DFINITY/RadixTree/Types.hs
+++ b/src/Network/DFINITY/RadixTree/Types.hs
@@ -1,4 +1,7 @@
 {-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE RecordWildCards #-}
 
 {-# OPTIONS -Wall #-}
@@ -8,7 +11,7 @@
    , RadixBranch(..)
    , RadixBuffer
    , RadixCache
-   , RadixDatabase
+   , RadixDatabase(..)
    , RadixError(..)
    , RadixPrefix(..)
    , RadixRoot
@@ -19,10 +22,11 @@
 import Codec.Serialise as CBOR (Serialise(..), serialise)
 import Codec.Serialise.Decoding (decodeBytes, decodeInt, decodeListLen)
 import Codec.Serialise.Encoding (encodeBytes, encodeInt, encodeListLen)
-import Crypto.Hash.SHA256 (hash)
 import Control.DeepSeq (NFData(..))
 import Control.Exception (Exception)
 import Control.Monad (void)
+import Control.Monad.Trans.Resource (MonadResource)
+import Crypto.Hash.SHA256 (hash)
 import Data.BloomFilter (Bloom)
 import Data.Bool (bool)
 import Data.ByteString.Base16 as Base16 (encode)
@@ -36,7 +40,7 @@
 import Data.Map.Strict (Map)
 import Data.Maybe (isJust)
 import Data.Monoid ((<>))
-import Database.LevelDB (DB)
+import Database.LevelDB (DB, Options, defaultReadOptions, defaultWriteOptions, get, open, put)
 import Text.Printf (printf)
 
 import Network.DFINITY.RadixTree.Bits
@@ -100,8 +104,16 @@
 
 type RadixCache = LruCache RadixRoot RadixBranch
 
-type RadixDatabase = DB
+class Monad m => RadixDatabase config m database | database -> config where
+   create :: config -> m database
+   load :: database -> ByteString -> m (Maybe ByteString)
+   store :: database -> ByteString -> ByteString -> m ()
 
+instance MonadResource m => RadixDatabase (FilePath, Options) m DB where
+   create = uncurry open
+   load database = get database defaultReadOptions
+   store database = put database defaultWriteOptions
+
 data RadixError
    = InvalidArgument String
    | StateRootDoesNotExist RadixRoot
@@ -147,7 +159,7 @@
 
 type RadixSearchResult = (NonEmpty RadixRoot, NonEmpty RadixBranch, NonEmpty [Bool], [Bool], [Bool], RadixCache)
 
-data RadixTree
+data RadixTree database
    = RadixTree
    { _radixBloom :: RadixBloom
    , _radixBloomSize :: Int
@@ -155,6 +167,6 @@
    , _radixCache :: RadixCache
    , _radixCacheSize :: Int
    , _radixCheckpoint :: RadixRoot
-   , _radixDatabase :: RadixDatabase
+   , _radixDatabase :: database
    , _radixRoot :: RadixRoot
    }
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -10,7 +10,7 @@
 
 import Control.Monad (foldM_, mzero)
 import Control.Monad.IO.Class (MonadIO(..))
-import Control.Monad.Trans.Resource (runResourceT)
+import Control.Monad.Trans.Resource (MonadResource, runResourceT)
 import Data.Aeson (FromJSON(..), Object, Value(..), eitherDecode)
 import Data.ByteString.Base16 (decode, encode)
 import Data.ByteString.Char8 (ByteString, unpack)
@@ -20,19 +20,20 @@
 import Data.HashMap.Strict as Map (elems, lookup)
 import Data.Text as Text (Text, drop)
 import Data.Text.Encoding (encodeUtf8)
+import Database.LevelDB (DB, Options(..))
 import System.Console.CmdArgs (Data, cmdArgs)
 
 import Network.DFINITY.RadixTree
 
 data Args
    = Args
-   { database :: FilePath
-   , file :: FilePath
+   { json :: FilePath
+   , path :: FilePath
    , test :: String
    } deriving Data
 
 instance Default Args where
-   def = Args "test/testdb" "test/tests.json" "*"
+   def = Args "test/tests.json" "test/testdb" "*"
 
 data Op
    = Insert ByteString ByteString
@@ -53,7 +54,9 @@
       Merkleize value -> "Merkleize" ++ pretty value
       where pretty = mappend " 0x" . unpack . encode
 
-parse :: Object -> Maybe Op
+parse
+   :: Object
+   -> Maybe Op
 parse object = do
    op <- Map.lookup "op" object
    case op of
@@ -63,14 +66,21 @@
       "stateRoot" -> Merkleize <$> get "value" object
       _ -> Nothing
 
-get :: Text -> Object -> Maybe ByteString
+get
+   :: Text
+   -> Object
+   -> Maybe ByteString
 get key object = do
    value <- Map.lookup key object
    case value of
       String text -> Just $ fst $ decode $ encodeUtf8 $ Text.drop 2 text
       _ -> Nothing
 
-step :: MonadIO m => RadixTree -> Op -> m RadixTree
+step
+   :: MonadResource m
+   => RadixTree DB
+   -> Op
+   -> m (RadixTree DB)
 step tree op = do
    liftIO $ print op
    case op of
@@ -109,11 +119,12 @@
 main :: IO ()
 main = do
    Args {..} <- cmdArgs def
-   contents <- Lazy.readFile file
+   contents <- Lazy.readFile json
    case eitherDecode contents of
       Left err -> fail err
       Right vctors -> runResourceT $ do
-         tree <- createRadixTree 100 100 database Nothing
+         let options = def {createIfMissing = True}
+         tree <- createRadixTree 262144 2048 Nothing (path, options)
          if test == "*"
          then foldM_ step tree `mapM_` elems vctors
          else case Map.lookup test vctors of