diff --git a/Cargo.toml b/Cargo.toml
index 808ed57b16..30582f1570 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -47,6 +47,7 @@ substrate-subxt-proc-macro = { version = "0.9.0", path = "proc-macro" }
 async-std = { version = "=1.5.0", features = ["attributes"] }
 env_logger = "0.7.1"
 wabt = "0.9.2"
+wabt-sys = "=0.7.1" # pinned because 0.7.2 fails to compile
 frame-system = { version = "2.0.0-rc4", package = "frame-system" }
 pallet-balances = { version = "2.0.0-rc4", package = "pallet-balances" }
 sp-keyring = { version = "2.0.0-rc4", package = "sp-keyring" }
diff --git a/src/extra.rs b/src/extrinsic/extra.rs
similarity index 97%
rename from src/extra.rs
rename to src/extrinsic/extra.rs
index fa7ff54a55..f31cec25b8 100644
--- a/src/extra.rs
+++ b/src/extrinsic/extra.rs
@@ -28,11 +28,17 @@ use sp_runtime::{
     transaction_validity::TransactionValidityError,
 };
 
-use crate::frame::{
-    balances::Balances,
-    system::System,
+use crate::{
+    frame::{
+        balances::Balances,
+        system::System,
+    },
+    runtimes::Runtime,
 };
 
+/// Extra type.
+pub type Extra<T> = <<T as Runtime>::Extra as SignedExtra<T>>::Extra;
+
 /// SignedExtra checks copied from substrate, in order to remove requirement to implement
 /// substrate's `frame_system::Trait`
 
diff --git a/src/extrinsic/mod.rs b/src/extrinsic/mod.rs
new file mode 100644
index 0000000000..70b50c9a11
--- /dev/null
+++ b/src/extrinsic/mod.rs
@@ -0,0 +1,82 @@
+// Copyright 2019-2020 Parity Technologies (UK) Ltd.
+// This file is part of substrate-subxt.
+//
+// subxt is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// subxt is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with substrate-subxt.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Create signed or unsigned extrinsics.
+
+mod extra;
+mod signer;
+
+pub use self::{
+    extra::{
+        DefaultExtra,
+        Extra,
+        SignedExtra,
+    },
+    signer::{
+        PairSigner,
+        Signer,
+    },
+};
+
+use sp_runtime::traits::SignedExtension;
+use sp_version::RuntimeVersion;
+
+use crate::{
+    frame::system::System,
+    runtimes::Runtime,
+    Encoded,
+    Error,
+};
+
+/// UncheckedExtrinsic type.
+pub type UncheckedExtrinsic<T> = sp_runtime::generic::UncheckedExtrinsic<
+    <T as System>::Address,
+    Encoded,
+    <T as Runtime>::Signature,
+    Extra<T>,
+>;
+
+/// SignedPayload type.
+pub type SignedPayload<T> = sp_runtime::generic::SignedPayload<Encoded, Extra<T>>;
+
+/// Creates a signed extrinsic
+pub async fn create_signed<T>(
+    runtime_version: &RuntimeVersion,
+    genesis_hash: T::Hash,
+    nonce: T::Index,
+    call: Encoded,
+    signer: &(dyn Signer<T> + Send + Sync),
+) -> Result<UncheckedExtrinsic<T>, Error>
+where
+    T: Runtime,
+    <<T::Extra as SignedExtra<T>>::Extra as SignedExtension>::AdditionalSigned:
+        Send + Sync,
+{
+    let spec_version = runtime_version.spec_version;
+    let tx_version = runtime_version.transaction_version;
+    let extra: T::Extra = T::Extra::new(spec_version, tx_version, nonce, genesis_hash);
+    let payload = SignedPayload::<T>::new(call, extra.extra())?;
+    let signed = signer.sign(payload).await?;
+    Ok(signed)
+}
+
+/// Creates an unsigned extrinsic
+pub fn create_unsigned<T>(call: Encoded) -> UncheckedExtrinsic<T>
+where
+    T: Runtime,
+{
+    UncheckedExtrinsic::<T>::new_unsigned(call)
+}
diff --git a/src/signer.rs b/src/extrinsic/signer.rs
similarity index 96%
rename from src/signer.rs
rename to src/extrinsic/signer.rs
index ebbcd41654..13ff50a366 100644
--- a/src/signer.rs
+++ b/src/extrinsic/signer.rs
@@ -17,14 +17,12 @@
 //! A library to **sub**mit e**xt**rinsics to a
 //! [substrate](https://github.com/paritytech/substrate) node via RPC.
 
-use crate::{
-    extra::SignedExtra,
-    runtimes::{
-        Runtime,
-        SignedPayload,
-        UncheckedExtrinsic,
-    },
+use super::{
+    SignedExtra,
+    SignedPayload,
+    UncheckedExtrinsic,
 };
+use crate::runtimes::Runtime;
 use codec::Encode;
 use sp_core::Pair;
 use sp_runtime::traits::{
diff --git a/src/frame/balances.rs b/src/frame/balances.rs
index bb1bdad498..4c210ce748 100644
--- a/src/frame/balances.rs
+++ b/src/frame/balances.rs
@@ -115,7 +115,7 @@ mod tests {
             RuntimeError,
         },
         events::EventsDecoder,
-        signer::{
+        extrinsic::{
             PairSigner,
             Signer,
         },
diff --git a/src/frame/sudo.rs b/src/frame/sudo.rs
index 541a923bfc..8efb336b7d 100644
--- a/src/frame/sudo.rs
+++ b/src/frame/sudo.rs
@@ -44,8 +44,8 @@ mod tests {
     use super::*;
     use crate::{
         error::Error,
+        extrinsic::PairSigner,
         frame::balances::TransferCall,
-        signer::PairSigner,
         tests::{
             test_client,
             TestRuntime,
diff --git a/src/lib.rs b/src/lib.rs
index 23927e7df3..c833c93228 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -60,17 +60,16 @@ use sp_core::{
     Bytes,
 };
 pub use sp_runtime::traits::SignedExtension;
-use sp_version::RuntimeVersion;
+pub use sp_version::RuntimeVersion;
 use std::marker::PhantomData;
 
 mod error;
 mod events;
-mod extra;
+pub mod extrinsic;
 mod frame;
 mod metadata;
 mod rpc;
 mod runtimes;
-mod signer;
 mod subscription;
 
 pub use crate::{
@@ -79,7 +78,12 @@ pub use crate::{
         EventsDecoder,
         RawEvent,
     },
-    extra::*,
+    extrinsic::{
+        PairSigner,
+        SignedExtra,
+        Signer,
+        UncheckedExtrinsic,
+    },
     frame::*,
     metadata::{
         Metadata,
@@ -90,7 +94,6 @@ pub use crate::{
         ExtrinsicSuccess,
     },
     runtimes::*,
-    signer::*,
     subscription::*,
     substrate_subxt_proc_macro::*,
 };
@@ -311,49 +314,13 @@ impl<T: Runtime> Client<T> {
             .and_then(|module| module.call(C::FUNCTION, call))?)
     }
 
-    /// Creates an payload for an extrinsic.
-    ///
-    /// If `nonce` is `None` the nonce will be fetched from the chain.
-    pub async fn create_payload<C: Call<T>>(
-        &self,
-        call: C,
-        account_id: &<T as System>::AccountId,
-        nonce: Option<T::Index>,
-    ) -> Result<SignedPayload<T>, Error>
-    where
-        <<T::Extra as SignedExtra<T>>::Extra as SignedExtension>::AdditionalSigned:
-            Send + Sync,
-    {
-        let account_nonce = if let Some(nonce) = nonce {
-            nonce
-        } else {
-            self.account(account_id, None).await?.nonce
-        };
-        let spec_version = self.runtime_version.spec_version;
-        let tx_version = self.runtime_version.transaction_version;
-        let genesis_hash = self.genesis_hash;
-        let call = self.encode(call)?;
-        let extra: T::Extra =
-            T::Extra::new(spec_version, tx_version, account_nonce, genesis_hash);
-        let raw_payload = SignedPayload::<T>::new(call, extra.extra())?;
-        Ok(raw_payload)
-    }
-
     /// Creates an unsigned extrinsic.
-    pub async fn create_unsigned<C: Call<T> + Send + Sync>(
+    pub fn create_unsigned<C: Call<T> + Send + Sync>(
         &self,
         call: C,
-        account_id: &<T as System>::AccountId,
-        nonce: Option<T::Index>,
-    ) -> Result<UncheckedExtrinsic<T>, Error>
-    where
-        <<T::Extra as SignedExtra<T>>::Extra as SignedExtension>::AdditionalSigned:
-            Send + Sync,
-    {
-        let payload = self.create_payload(call, account_id, nonce).await?;
-        let (call, _, _) = payload.deconstruct();
-        let unsigned = UncheckedExtrinsic::<T>::new_unsigned(call);
-        Ok(unsigned)
+    ) -> Result<UncheckedExtrinsic<T>, Error> {
+        let call = self.encode(call)?;
+        Ok(extrinsic::create_unsigned::<T>(call))
     }
 
     /// Creates a signed extrinsic.
@@ -366,10 +333,20 @@ impl<T: Runtime> Client<T> {
         <<T::Extra as SignedExtra<T>>::Extra as SignedExtension>::AdditionalSigned:
             Send + Sync,
     {
-        let payload = self
-            .create_payload(call, signer.account_id(), signer.nonce())
-            .await?;
-        let signed = signer.sign(payload).await?;
+        let account_nonce = if let Some(nonce) = signer.nonce() {
+            nonce
+        } else {
+            self.account(signer.account_id(), None).await?.nonce
+        };
+        let call = self.encode(call)?;
+        let signed = extrinsic::create_signed(
+            &self.runtime_version,
+            self.genesis_hash,
+            account_nonce,
+            call,
+            signer,
+        )
+        .await?;
         Ok(signed)
     }
 
@@ -479,19 +456,11 @@ impl codec::Encode for Encoded {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use codec::Encode;
-    use sp_core::{
-        storage::{
-            well_known_keys,
-            StorageKey,
-        },
-        Pair,
-    };
-    use sp_keyring::{
-        AccountKeyring,
-        Ed25519Keyring,
+    use sp_core::storage::{
+        well_known_keys,
+        StorageKey,
     };
-    use sp_runtime::MultiSignature;
+    use sp_keyring::AccountKeyring;
     use substrate_subxt_client::{
         DatabaseConfig,
         KeystoreConfig,
@@ -640,47 +609,4 @@ mod tests {
         let mut blocks = client.subscribe_finalized_blocks().await.unwrap();
         blocks.next().await;
     }
-
-    #[async_std::test]
-    async fn test_create_raw_payload() {
-        let signer_pair = Ed25519Keyring::Alice.pair();
-        let signer_account_id = Ed25519Keyring::Alice.to_account_id();
-        let dest = AccountKeyring::Bob.to_account_id().into();
-
-        let (client, _) = test_client().await;
-
-        // create raw payload with AccoundId and sign it
-        let raw_payload = client
-            .create_payload(
-                balances::TransferCall {
-                    to: &dest,
-                    amount: 10_000,
-                },
-                &signer_account_id,
-                None,
-            )
-            .await
-            .unwrap();
-        let raw_signature = signer_pair.sign(raw_payload.encode().as_slice());
-        let raw_multisig = MultiSignature::from(raw_signature);
-
-        // create signature with Xtbuilder
-        let signer = PairSigner::new(Ed25519Keyring::Alice.pair());
-        let xt_multi_sig = client
-            .create_signed(
-                balances::TransferCall {
-                    to: &dest,
-                    amount: 10_000,
-                },
-                &signer,
-            )
-            .await
-            .unwrap()
-            .signature
-            .unwrap()
-            .1;
-
-        // compare signatures
-        assert_eq!(raw_multisig, xt_multi_sig);
-    }
 }
diff --git a/src/runtimes.rs b/src/runtimes.rs
index 0f23635158..13779d71b8 100644
--- a/src/runtimes.rs
+++ b/src/runtimes.rs
@@ -27,7 +27,7 @@ use sp_runtime::{
 };
 
 use crate::{
-    extra::{
+    extrinsic::{
         DefaultExtra,
         SignedExtra,
     },
@@ -40,7 +40,6 @@ use crate::{
         sudo::Sudo,
         system::System,
     },
-    Encoded,
 };
 
 /// Runtime trait.
@@ -51,20 +50,6 @@ pub trait Runtime: System + Sized + Send + Sync + 'static {
     type Extra: SignedExtra<Self> + Send + Sync + 'static;
 }
 
-/// Extra type.
-pub type Extra<T> = <<T as Runtime>::Extra as SignedExtra<T>>::Extra;
-
-/// UncheckedExtrinsic type.
-pub type UncheckedExtrinsic<T> = sp_runtime::generic::UncheckedExtrinsic<
-    <T as System>::Address,
-    Encoded,
-    <T as Runtime>::Signature,
-    Extra<T>,
->;
-
-/// SignedPayload type.
-pub type SignedPayload<T> = sp_runtime::generic::SignedPayload<Encoded, Extra<T>>;
-
 /// Concrete type definitions compatible with those in the default substrate `node_runtime`
 ///
 /// # Note