diff --git a/substrate/core/consensus/aura/primitives/src/lib.rs b/substrate/core/consensus/aura/primitives/src/lib.rs
index c37677283f..27f9a123bc 100644
--- a/substrate/core/consensus/aura/primitives/src/lib.rs
+++ b/substrate/core/consensus/aura/primitives/src/lib.rs
@@ -18,36 +18,16 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-/// The ApiIds for Aura authorship API.
-pub mod id {
-	use substrate_client::runtime_api::ApiId;
+use substrate_client::decl_runtime_apis;
 
-	/// ApiId for the AuraApi trait.
-	pub const AURA_API: ApiId = *b"aura_api";
-}
-
-/// Aura consensus environmental data. Useful for block-proposing code.
-pub struct AuraConsensusData {
-	/// The timestamp the block should be authored with.
-	pub timestamp: u64,
-	/// The slot number.
-	pub slot: u64,
-	/// The duration of the slot, in seconds.
-	pub slot_duration: u64,
-}
-
-/// Runtime-APIs
-pub mod api {
-	use substrate_client::decl_runtime_apis;
-	decl_runtime_apis! {
-		/// API necessary for block authorship with aura.
-		pub trait AuraApi {
-			/// Return the slot duration in seconds for Aura.
-			/// Currently, only the value provided by this type at genesis
-			/// will be used.
-			///
-			/// Dynamic slot duration may be supported in the future.
-			fn slot_duration() -> u64;
-		}
+decl_runtime_apis! {
+	/// API necessary for block authorship with aura.
+	pub trait AuraApi {
+		/// Return the slot duration in seconds for Aura.
+		/// Currently, only the value provided by this type at genesis
+		/// will be used.
+		///
+		/// Dynamic slot duration may be supported in the future.
+		fn slot_duration() -> u64;
 	}
 }
diff --git a/substrate/core/consensus/aura/src/lib.rs b/substrate/core/consensus/aura/src/lib.rs
index f3ab407dce..8030713e56 100644
--- a/substrate/core/consensus/aura/src/lib.rs
+++ b/substrate/core/consensus/aura/src/lib.rs
@@ -47,7 +47,6 @@ use inherents::{InherentDataProviders, InherentData, RuntimeString};
 
 use futures::{Stream, Future, IntoFuture, future::{self, Either}};
 use tokio::timer::Timeout;
-use api::AuraApi;
 use slots::Slots;
 use ::log::{warn, debug, log, info, trace};
 
@@ -632,6 +631,11 @@ impl SlotDuration {
 			}
 		}
 	}
+
+	/// Returns slot duration value.
+	pub fn get(&self) -> u64 {
+		self.0
+	}
 }
 
 /// Register the aura inherent data provider, if not registered already.
diff --git a/substrate/core/test-runtime/src/lib.rs b/substrate/core/test-runtime/src/lib.rs
index e60025de31..1fa263670a 100644
--- a/substrate/core/test-runtime/src/lib.rs
+++ b/substrate/core/test-runtime/src/lib.rs
@@ -67,7 +67,6 @@ pub use primitives::hash::H256;
 use primitives::{Ed25519AuthorityId, OpaqueMetadata};
 #[cfg(any(feature = "std", test))]
 use runtime_version::NativeVersion;
-use consensus_aura::api as aura_api;
 use inherents::{CheckInherentsResult, InherentData};
 
 /// Test runtime version.
@@ -278,7 +277,7 @@ impl_runtime_apis! {
 		}
 	}
 
-	impl aura_api::AuraApi<Block> for Runtime {
+	impl consensus_aura::AuraApi<Block> for Runtime {
 		fn slot_duration() -> u64 { 1 }
 	}
 }
diff --git a/substrate/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm b/substrate/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm
index edede7bdd5..16a56bcade 100644
Binary files a/substrate/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm and b/substrate/core/test-runtime/wasm/target/wasm32-unknown-unknown/release/substrate_test_runtime.compact.wasm differ
diff --git a/substrate/node/runtime/src/lib.rs b/substrate/node/runtime/src/lib.rs
index f25a46f267..1bc0b3d912 100644
--- a/substrate/node/runtime/src/lib.rs
+++ b/substrate/node/runtime/src/lib.rs
@@ -80,7 +80,6 @@ use council::seats as council_seats;
 #[cfg(any(feature = "std", test))]
 use version::NativeVersion;
 use substrate_primitives::OpaqueMetadata;
-use consensus_aura::api as aura_api;
 
 #[cfg(any(feature = "std", test))]
 pub use runtime_primitives::BuildStorage;
@@ -335,7 +334,7 @@ impl_runtime_apis! {
 		}
 	}
 
-	impl aura_api::AuraApi<Block> for Runtime {
+	impl consensus_aura::AuraApi<Block> for Runtime {
 		fn slot_duration() -> u64 {
 			Aura::slot_duration()
 		}
diff --git a/substrate/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm b/substrate/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm
index 25c28b6eb8..d8eedb7468 100644
Binary files a/substrate/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm and b/substrate/node/runtime/wasm/target/wasm32-unknown-unknown/release/node_runtime.compact.wasm differ