diff --git a/crates/blockifier/src/execution/contract_class.rs b/crates/blockifier/src/execution/contract_class.rs
index 4e182ed837..1e257619b7 100644
--- a/crates/blockifier/src/execution/contract_class.rs
+++ b/crates/blockifier/src/execution/contract_class.rs
@@ -56,6 +56,17 @@ pub enum ContractClass {
     V1(ContractClassV1),
 }
 
+impl TryFrom<starknet_api::contract_class::ContractClass> for ContractClass {
+    type Error = ProgramError;
+
+    fn try_from(
+        contract_class: starknet_api::contract_class::ContractClass,
+    ) -> Result<Self, Self::Error> {
+        let starknet_api::contract_class::ContractClass::V1(contract_class_v1) = contract_class;
+        Ok(ContractClass::V1(contract_class_v1.try_into()?))
+    }
+}
+
 impl ContractClass {
     pub fn constructor_selector(&self) -> Option<EntryPointSelector> {
         match self {
@@ -356,6 +367,18 @@ impl EntryPointV1 {
     }
 }
 
+impl TryFrom<starknet_api::contract_class::ContractClassV1> for ContractClassV1 {
+    type Error = ProgramError;
+
+    fn try_from(
+        contract_class: starknet_api::contract_class::ContractClassV1,
+    ) -> Result<Self, Self::Error> {
+        let starknet_api::contract_class::ContractClassV1::Casm(casm_contract_class) =
+            contract_class;
+        casm_contract_class.try_into()
+    }
+}
+
 impl TryFrom<CasmContractClass> for ContractClassV1 {
     type Error = ProgramError;
 
@@ -475,6 +498,21 @@ pub struct ClassInfo {
     abi_length: usize,
 }
 
+impl TryFrom<starknet_api::contract_class::ClassInfo> for ClassInfo {
+    type Error = ProgramError;
+
+    fn try_from(class_info: starknet_api::contract_class::ClassInfo) -> Result<Self, Self::Error> {
+        let starknet_api::contract_class::ClassInfo {
+            contract_class,
+            sierra_program_length,
+            abi_length,
+        } = class_info;
+
+        let contract_class: ContractClass = contract_class.try_into()?;
+        Ok(Self { contract_class, sierra_program_length, abi_length })
+    }
+}
+
 impl ClassInfo {
     pub fn bytecode_length(&self) -> usize {
         self.contract_class.bytecode_length()
diff --git a/crates/blockifier/src/transaction/errors.rs b/crates/blockifier/src/transaction/errors.rs
index 70b9fbe6ab..cbd9d38085 100644
--- a/crates/blockifier/src/transaction/errors.rs
+++ b/crates/blockifier/src/transaction/errors.rs
@@ -1,3 +1,4 @@
+use cairo_vm::types::errors::program_errors::ProgramError;
 use num_bigint::BigUint;
 use starknet_api::core::{ClassHash, ContractAddress, EntryPointSelector, Nonce};
 use starknet_api::transaction::{Fee, TransactionVersion};
@@ -109,6 +110,8 @@ pub enum TransactionExecutionError {
          not."
     )]
     InvalidSegmentStructure(usize, usize),
+    #[error(transparent)]
+    ProgramError(#[from] ProgramError),
 }
 
 #[derive(Debug, Error)]
diff --git a/crates/blockifier/src/transaction/transactions.rs b/crates/blockifier/src/transaction/transactions.rs
index 834660c740..8bdd466b50 100644
--- a/crates/blockifier/src/transaction/transactions.rs
+++ b/crates/blockifier/src/transaction/transactions.rs
@@ -135,6 +135,16 @@ pub struct DeclareTransaction {
     pub class_info: ClassInfo,
 }
 
+impl TryFrom<starknet_api::executable_transaction::DeclareTransaction> for DeclareTransaction {
+    type Error = TransactionExecutionError;
+
+    fn try_from(
+        declare_tx: starknet_api::executable_transaction::DeclareTransaction,
+    ) -> Result<Self, Self::Error> {
+        Self::new_from_executable_tx(declare_tx, false)
+    }
+}
+
 impl DeclareTransaction {
     fn create(
         declare_tx: starknet_api::transaction::DeclareTransaction,
@@ -163,6 +173,17 @@ impl DeclareTransaction {
         Self::create(declare_tx, tx_hash, class_info, true)
     }
 
+    fn new_from_executable_tx(
+        declare_tx: starknet_api::executable_transaction::DeclareTransaction,
+        only_query: bool,
+    ) -> Result<Self, TransactionExecutionError> {
+        let starknet_api::executable_transaction::DeclareTransaction { tx, tx_hash, class_info } =
+            declare_tx;
+        let class_info: ClassInfo = class_info.try_into()?;
+
+        Self::create(tx, tx_hash, class_info, only_query)
+    }
+
     implement_inner_tx_getter_calls!((class_hash, ClassHash), (signature, TransactionSignature));
 
     pub fn tx(&self) -> &starknet_api::transaction::DeclareTransaction {
diff --git a/crates/starknet_api/src/contract_class.rs b/crates/starknet_api/src/contract_class.rs
new file mode 100644
index 0000000000..8d9d1be4ec
--- /dev/null
+++ b/crates/starknet_api/src/contract_class.rs
@@ -0,0 +1,22 @@
+use cairo_lang_starknet_classes::casm_contract_class::CasmContractClass;
+
+/// Compiled contract class.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum ContractClass {
+    V1(ContractClassV1),
+}
+
+/// Compiled contract class variant for Cairo 1 contracts.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum ContractClassV1 {
+    Casm(CasmContractClass),
+}
+
+/// All relevant information about a declared contract class, including the compiled contract class
+/// and other parameters derived from the original declare transaction required for billing.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct ClassInfo {
+    pub contract_class: ContractClass,
+    pub sierra_program_length: usize,
+    pub abi_length: usize,
+}
diff --git a/crates/starknet_api/src/executable_transaction.rs b/crates/starknet_api/src/executable_transaction.rs
index 40ac70a97a..b7ebff021a 100644
--- a/crates/starknet_api/src/executable_transaction.rs
+++ b/crates/starknet_api/src/executable_transaction.rs
@@ -1,5 +1,5 @@
+use crate::contract_class::ClassInfo;
 use crate::core::{ContractAddress, Nonce};
-use crate::state::ContractClass;
 use crate::transaction::{Tip, TransactionHash};
 
 /// Represents a paid Starknet transaction.
@@ -73,11 +73,3 @@ pub struct InvokeTransaction {
     pub tx: crate::transaction::InvokeTransaction,
     pub tx_hash: TransactionHash,
 }
-
-#[derive(Clone, Debug, Eq, PartialEq)]
-pub struct ClassInfo {
-    // TODO: use compiled contract class.
-    pub contract_class: ContractClass,
-    pub sierra_program_length: usize,
-    pub abi_length: usize,
-}
diff --git a/crates/starknet_api/src/lib.rs b/crates/starknet_api/src/lib.rs
index 6e91d89ff0..0b335dcfc2 100644
--- a/crates/starknet_api/src/lib.rs
+++ b/crates/starknet_api/src/lib.rs
@@ -4,6 +4,7 @@
 
 pub mod block;
 pub mod block_hash;
+pub mod contract_class;
 pub mod core;
 pub mod crypto;
 pub mod data_availability;