diff --git a/crates/starknet-devnet-server/src/api/json_rpc/models.rs b/crates/starknet-devnet-server/src/api/json_rpc/models.rs
index 41a8ce526..8ed72934b 100644
--- a/crates/starknet-devnet-server/src/api/json_rpc/models.rs
+++ b/crates/starknet-devnet-server/src/api/json_rpc/models.rs
@@ -180,10 +180,12 @@ pub struct L1TransactionHashInput {
     pub transaction_hash: Hash256,
 }
 
+pub type SubscriptionId = u64;
+
 #[derive(Deserialize, Clone, Debug)]
 #[serde(deny_unknown_fields)]
 pub struct SubscriptionIdInput {
-    pub subscription_id: i64,
+    pub subscription_id: SubscriptionId,
 }
 
 #[derive(Deserialize, Clone, Debug)]
diff --git a/crates/starknet-devnet-server/src/subscribe.rs b/crates/starknet-devnet-server/src/subscribe.rs
index b136ac638..59ec6163f 100644
--- a/crates/starknet-devnet-server/src/subscribe.rs
+++ b/crates/starknet-devnet-server/src/subscribe.rs
@@ -15,12 +15,11 @@ use starknet_types::rpc::transactions::{TransactionStatus, TransactionWithHash};
 use tokio::sync::Mutex;
 
 use crate::api::json_rpc::error::ApiError;
+use crate::api::json_rpc::models::SubscriptionId;
 use crate::rpc_core::request::Id;
 
 pub type SocketId = u64;
 
-type SubscriptionId = i64;
-
 #[derive(Debug)]
 pub struct AddressFilter {
     address_container: Vec<ContractAddress>,
diff --git a/crates/starknet-devnet/tests/common/utils.rs b/crates/starknet-devnet/tests/common/utils.rs
index b2adae5e9..8ed41736a 100644
--- a/crates/starknet-devnet/tests/common/utils.rs
+++ b/crates/starknet-devnet/tests/common/utils.rs
@@ -434,13 +434,15 @@ pub async fn send_binary_rpc_via_ws(
     Ok(resp_body)
 }
 
+pub type SubscriptionId = u64;
+
 pub async fn subscribe(
     ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
     subscription_method: &str,
     params: serde_json::Value,
-) -> Result<i64, anyhow::Error> {
+) -> Result<SubscriptionId, anyhow::Error> {
     let subscription_confirmation = send_text_rpc_via_ws(ws, subscription_method, params).await?;
-    subscription_confirmation["result"].as_i64().ok_or(anyhow::Error::msg(format!(
+    subscription_confirmation["result"].as_u64().ok_or(anyhow::Error::msg(format!(
         "No ID in subscription response: {subscription_confirmation}"
     )))
 }
@@ -459,7 +461,7 @@ pub async fn receive_rpc_via_ws(
 pub async fn receive_notification(
     ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
     method: &str,
-    expected_subscription_id: i64,
+    expected_subscription_id: SubscriptionId,
 ) -> Result<serde_json::Value, anyhow::Error> {
     let mut notification = receive_rpc_via_ws(ws).await?;
     assert_eq!(notification["jsonrpc"], "2.0");
@@ -479,13 +481,13 @@ pub async fn assert_no_notifications(ws: &mut WebSocketStream<MaybeTlsStream<Tcp
 pub async fn subscribe_new_heads(
     ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
     block_specifier: serde_json::Value,
-) -> Result<i64, anyhow::Error> {
+) -> Result<SubscriptionId, anyhow::Error> {
     subscribe(ws, "starknet_subscribeNewHeads", block_specifier).await
 }
 
 pub async fn unsubscribe(
     ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
-    subscription_id: i64,
+    subscription_id: SubscriptionId,
 ) -> Result<serde_json::Value, anyhow::Error> {
     send_text_rpc_via_ws(ws, "starknet_unsubscribe", json!({ "subscription_id": subscription_id }))
         .await
diff --git a/crates/starknet-devnet/tests/test_subscription_to_blocks.rs b/crates/starknet-devnet/tests/test_subscription_to_blocks.rs
index c7dfa7a6a..d96a26fd8 100644
--- a/crates/starknet-devnet/tests/test_subscription_to_blocks.rs
+++ b/crates/starknet-devnet/tests/test_subscription_to_blocks.rs
@@ -15,11 +15,12 @@ mod block_subscription_support {
     use crate::common::background_devnet::BackgroundDevnet;
     use crate::common::utils::{
         assert_no_notifications, receive_notification, subscribe_new_heads, unsubscribe,
+        SubscriptionId,
     };
 
     async fn receive_block(
         ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
-        subscription_id: i64,
+        subscription_id: SubscriptionId,
     ) -> Result<serde_json::Value, anyhow::Error> {
         receive_notification(ws, "starknet_subscriptionNewHeads", subscription_id).await
     }
diff --git a/crates/starknet-devnet/tests/test_subscription_to_events.rs b/crates/starknet-devnet/tests/test_subscription_to_events.rs
index 819b80855..7ee720dd2 100644
--- a/crates/starknet-devnet/tests/test_subscription_to_events.rs
+++ b/crates/starknet-devnet/tests/test_subscription_to_events.rs
@@ -20,19 +20,19 @@ mod event_subscription_support {
     use crate::common::utils::{
         assert_no_notifications, declare_v3_deploy_v3,
         get_events_contract_in_sierra_and_compiled_class_hash, receive_notification,
-        receive_rpc_via_ws, subscribe, unsubscribe,
+        receive_rpc_via_ws, subscribe, unsubscribe, SubscriptionId,
     };
 
     async fn subscribe_events(
         ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
         params: serde_json::Value,
-    ) -> Result<i64, anyhow::Error> {
+    ) -> Result<SubscriptionId, anyhow::Error> {
         subscribe(ws, "starknet_subscribeEvents", params).await
     }
 
     async fn receive_event(
         ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
-        subscription_id: i64,
+        subscription_id: SubscriptionId,
     ) -> Result<serde_json::Value, anyhow::Error> {
         receive_notification(ws, "starknet_subscriptionEvents", subscription_id).await
     }
diff --git a/crates/starknet-devnet/tests/test_subscription_to_pending_txs.rs b/crates/starknet-devnet/tests/test_subscription_to_pending_txs.rs
index 1fc55b1d6..d5702a1e5 100644
--- a/crates/starknet-devnet/tests/test_subscription_to_pending_txs.rs
+++ b/crates/starknet-devnet/tests/test_subscription_to_pending_txs.rs
@@ -17,13 +17,13 @@ mod pending_transactions_subscription_support {
     use crate::common::utils::{
         assert_no_notifications, declare_v3_deploy_v3,
         get_simple_contract_in_sierra_and_compiled_class_hash, receive_rpc_via_ws, subscribe,
-        unsubscribe,
+        unsubscribe, SubscriptionId,
     };
 
     async fn subscribe_pending_txs(
         ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
         params: serde_json::Value,
-    ) -> Result<i64, anyhow::Error> {
+    ) -> Result<SubscriptionId, anyhow::Error> {
         subscribe(ws, "starknet_subscribePendingTransactions", params).await
     }
 
diff --git a/crates/starknet-devnet/tests/test_subscription_to_reorg.rs b/crates/starknet-devnet/tests/test_subscription_to_reorg.rs
index 0735fac6d..d065c9551 100644
--- a/crates/starknet-devnet/tests/test_subscription_to_reorg.rs
+++ b/crates/starknet-devnet/tests/test_subscription_to_reorg.rs
@@ -99,7 +99,7 @@ mod reorg_subscription_support {
             // was received per subscription_id, we extract the IDs from notifications, store them
             // in a set, and later assert equality with the set of expected subscription IDs.
             let notification_id =
-                notification["params"]["subscription_id"].take().as_i64().unwrap();
+                notification["params"]["subscription_id"].take().as_u64().unwrap();
             notification_ids.insert(notification_id);
 
             assert_eq!(
diff --git a/crates/starknet-devnet/tests/test_subscription_to_tx_status.rs b/crates/starknet-devnet/tests/test_subscription_to_tx_status.rs
index b247419c6..d4eef8c51 100644
--- a/crates/starknet-devnet/tests/test_subscription_to_tx_status.rs
+++ b/crates/starknet-devnet/tests/test_subscription_to_tx_status.rs
@@ -10,13 +10,14 @@ mod tx_status_subscription_support {
     use crate::common::background_devnet::BackgroundDevnet;
     use crate::common::utils::{
         assert_no_notifications, receive_rpc_via_ws, subscribe, subscribe_new_heads, unsubscribe,
+        SubscriptionId,
     };
 
     async fn subscribe_tx_status(
         ws: &mut WebSocketStream<MaybeTlsStream<TcpStream>>,
         tx_hash: &Felt,
         block_id: Option<BlockId>,
-    ) -> Result<i64, anyhow::Error> {
+    ) -> Result<SubscriptionId, anyhow::Error> {
         let mut params = json!({ "transaction_hash": tx_hash });
 
         if let Some(block_id) = block_id {
@@ -38,7 +39,7 @@ mod tx_status_subscription_support {
     fn assert_successful_mint_notification(
         notification: serde_json::Value,
         tx_hash: Felt,
-        subscription_id: i64,
+        subscription_id: SubscriptionId,
     ) {
         assert_eq!(
             notification,