diff --git a/lib/core/src/Cardano/Wallet.hs b/lib/core/src/Cardano/Wallet.hs
index 4aca1c5722a..d70fa93dc3a 100644
--- a/lib/core/src/Cardano/Wallet.hs
+++ b/lib/core/src/Cardano/Wallet.hs
@@ -173,7 +173,8 @@ import qualified Data.Text.IO as TIO
 
 data WalletLayer s t = WalletLayer
     { createWallet
-        :: WalletId
+        :: (Show s, NFData s, IsOurs s, TxId t)
+        => WalletId
         -> WalletName
         -> s
         -> ExceptT ErrWalletAlreadyExists IO WalletId
@@ -218,7 +219,8 @@ data WalletLayer s t = WalletLayer
         -- apply remaining blocks until failure or, the target slot is reached.
 
     , listAddresses
-        :: WalletId
+        :: (IsOurs s, CompareDiscovery s, KnownAddresses s)
+        => WalletId
         -> ExceptT ErrNoSuchWallet IO [(Address, AddressState)]
         -- ^ List all addresses of a wallet with their metadata. Addresses
         -- are ordered from the most recently discovered to the oldest known.
@@ -234,7 +236,8 @@ data WalletLayer s t = WalletLayer
         -- sign) an actual transaction, have a look at 'signTx'.
 
     , signTx
-        :: WalletId
+        :: (Show s, NFData s, IsOwned s, GenChange s)
+        => WalletId
         -> Passphrase "encryption"
         -> CoinSelection
         -> ExceptT ErrSignTx IO (Tx, TxMeta, [TxWitness])
@@ -245,7 +248,8 @@ data WalletLayer s t = WalletLayer
         -- 'submitTx'.
 
     , submitTx
-        :: WalletId
+        :: (TxId t)
+        => WalletId
         -> (Tx, TxMeta, [TxWitness])
         -> ExceptT ErrSubmitTx IO ()
         -- ^ Broadcast a (signed) transaction to the network.
@@ -327,15 +331,7 @@ cancelWorker (WorkerRegistry mvar) wid =
 
 -- | Create a new instance of the wallet layer.
 newWalletLayer
-    :: forall s t.
-        ( IsOwned s
-        , GenChange s
-        , KnownAddresses s
-        , CompareDiscovery s
-        , NFData s
-        , Show s
-        , TxId t
-        )
+    :: forall s t. ()
     => DBLayer IO s t
     -> NetworkLayer t IO
     -> TransactionLayer t
@@ -362,7 +358,8 @@ newWalletLayer db nw tl = do
     ---------------------------------------------------------------------------}
 
     _createWallet
-        :: WalletId
+        :: (Show s, NFData s, IsOurs s, TxId t)
+        => WalletId
         -> WalletName
         -> s
         -> ExceptT ErrWalletAlreadyExists IO WalletId
@@ -532,7 +529,8 @@ newWalletLayer db nw tl = do
     -- This implementation is rather inneficient and not intented for frequent
     -- use, in particular for exchanges or "big-players".
     _listAddresses
-        :: WalletId
+        :: (IsOurs s, CompareDiscovery s, KnownAddresses s)
+        => WalletId
         -> ExceptT ErrNoSuchWallet IO [(Address, AddressState)]
     _listAddresses wid = do
         (s, txs) <- DB.withLock db $ (,)
@@ -573,7 +571,8 @@ newWalletLayer db nw tl = do
             adjustForFee feeOpts utxo' sel
 
     _signTx
-        :: WalletId
+        :: (Show s, NFData s, IsOwned s, GenChange s)
+        => WalletId
         -> Passphrase "encryption"
         -> CoinSelection
         -> ExceptT ErrSignTx IO (Tx, TxMeta, [TxWitness])
@@ -606,7 +605,8 @@ newWalletLayer db nw tl = do
                     throwE $ ErrSignTx e
 
     _submitTx
-        :: WalletId
+        :: (TxId t)
+        => WalletId
         -> (Tx, TxMeta, [TxWitness])
         -> ExceptT ErrSubmitTx IO ()
     _submitTx wid (tx, meta, wit) = do
diff --git a/lib/core/src/Cardano/Wallet/Api/Server.hs b/lib/core/src/Cardano/Wallet/Api/Server.hs
index 0d264098b5e..3d10673aceb 100644
--- a/lib/core/src/Cardano/Wallet/Api/Server.hs
+++ b/lib/core/src/Cardano/Wallet/Api/Server.hs
@@ -189,7 +189,10 @@ withListeningSocket mport = bracket acquire release
                                     Wallets
 -------------------------------------------------------------------------------}
 
-wallets :: KeyToAddress t => WalletLayer (SeqState t) t -> Server Wallets
+wallets
+    :: (TxId t, KeyToAddress t)
+    => WalletLayer (SeqState t) t
+    -> Server Wallets
 wallets w =
     deleteWallet w
     :<|> getWallet w
@@ -250,7 +253,7 @@ listWallets w = do
         mapM (getWalletWithCreationTime w) (ApiT <$> wids)
 
 postWallet
-    :: KeyToAddress t
+    :: (KeyToAddress t, TxId t)
     => WalletLayer (SeqState t) t
     -> WalletPostData
     -> Handler ApiWallet
@@ -295,11 +298,14 @@ putWalletPassphrase w (ApiT wid) body = do
                                     Addresses
 -------------------------------------------------------------------------------}
 
-addresses :: WalletLayer (SeqState t) t -> Server (Addresses t)
+addresses
+    :: KeyToAddress t
+    => WalletLayer (SeqState t) t
+    -> Server (Addresses t)
 addresses = listAddresses
 
 listAddresses
-    :: forall t. ()
+    :: forall t. (KeyToAddress t)
     => WalletLayer (SeqState t) t
     -> ApiT WalletId
     -> Maybe (ApiT AddressState)
@@ -318,11 +324,14 @@ listAddresses w (ApiT wid) stateFilter = do
                                     Transactions
 -------------------------------------------------------------------------------}
 
-transactions :: TxId t => WalletLayer (SeqState t) t -> Server (Transactions t)
+transactions
+    :: (TxId t, KeyToAddress t)
+    => WalletLayer (SeqState t) t
+    -> Server (Transactions t)
 transactions = createTransaction
 
 createTransaction
-    :: forall t. (TxId t)
+    :: forall t. (TxId t, KeyToAddress t)
     => WalletLayer (SeqState t) t
     -> ApiT WalletId
     -> PostTransactionData t