diff --git a/src/SmartTransactionsController.ts b/src/SmartTransactionsController.ts
index 06fdd38..3f4bd60 100644
--- a/src/SmartTransactionsController.ts
+++ b/src/SmartTransactionsController.ts
@@ -288,6 +288,14 @@ export class SmartTransactionsController extends StaticIntervalPollingController
 
   #trace: TraceCallback;
 
+  #isStxMigrationFlagEnabled(flagName: string): boolean {
+    const flag = this.messenger.call('RemoteFeatureFlagController:getState')
+      ?.remoteFeatureFlags?.[flagName];
+    return Boolean(
+      flag && typeof flag === 'object' && 'value' in flag && flag.value,
+    );
+  }
+
   /**
    * Validates the smart transactions feature flags from the remote feature flag controller
    * and reports any validation errors to Sentry via ErrorReportingService.
@@ -818,9 +826,13 @@ export class SmartTransactionsController extends StaticIntervalPollingController
     });
 
     // Construct the URL and fetch the data
+    const useSentinelForBatchStatus = this.#isStxMigrationFlagEnabled(
+      'stxMigrationBatchStatus',
+    );
     const url = `${getAPIRequestURL(
       APIType.BATCH_STATUS,
       chainId,
+      useSentinelForBatchStatus,
     )}?${params.toString()}`;
     const data = (await this.#fetch(url)) as Record<
       string,
@@ -912,15 +924,21 @@ export class SmartTransactionsController extends StaticIntervalPollingController
       );
     }
     transactions.push(unsignedTradeTransactionWithNonce);
+    const useSentinelForGetFees = this.#isStxMigrationFlagEnabled(
+      'stxMigrationGetFees',
+    );
     const data = await this.#trace(
       { name: SmartTransactionsTraceName.GetFees },
       async () =>
-        await this.#fetch(getAPIRequestURL(APIType.GET_FEES, chainId), {
-          method: 'POST',
-          body: JSON.stringify({
-            txs: transactions,
-          }),
-        }),
+        await this.#fetch(
+          getAPIRequestURL(APIType.GET_FEES, chainId, useSentinelForGetFees),
+          {
+            method: 'POST',
+            body: JSON.stringify({
+              txs: transactions,
+            }),
+          },
+        ),
     );
     let approvalTxFees: IndividualTxFees | null;
     let tradeTxFees: IndividualTxFees | null;
@@ -977,11 +995,18 @@ export class SmartTransactionsController extends StaticIntervalPollingController
     const ethQuery = this.#getEthQuery({
       networkClientId: selectedNetworkClientId,
     });
+    const useSentinelForSubmitTransactions = this.#isStxMigrationFlagEnabled(
+      'stxMigrationSubmitTransactions',
+    );
     const data = await this.#trace(
       { name: SmartTransactionsTraceName.SubmitTransactions },
       async () =>
         await this.#fetch(
-          getAPIRequestURL(APIType.SUBMIT_TRANSACTIONS, chainId),
+          getAPIRequestURL(
+            APIType.SUBMIT_TRANSACTIONS,
+            chainId,
+            useSentinelForSubmitTransactions,
+          ),
           {
             method: 'POST',
             body: JSON.stringify({
@@ -1129,13 +1154,18 @@ export class SmartTransactionsController extends StaticIntervalPollingController
     } = {},
   ): Promise<void> {
     const chainId = this.#getChainId({ networkClientId });
+    const useSentinelForCancel =
+      this.#isStxMigrationFlagEnabled('stxMigrationCancel');
     await this.#trace(
       { name: SmartTransactionsTraceName.CancelTransaction },
       async () =>
-        await this.#fetch(getAPIRequestURL(APIType.CANCEL, chainId), {
-          method: 'POST',
-          body: JSON.stringify({ uuid }),
-        }),
+        await this.#fetch(
+          getAPIRequestURL(APIType.CANCEL, chainId, useSentinelForCancel),
+          {
+            method: 'POST',
+            body: JSON.stringify({ uuid }),
+          },
+        ),
     );
   }
 
diff --git a/src/utils.test.ts b/src/utils.test.ts
index 8ad50b2..db936b5 100644
--- a/src/utils.test.ts
+++ b/src/utils.test.ts
@@ -118,6 +118,123 @@ describe('src/utils.js', () => {
         `${SENTINEL_API_BASE_URL_MAP[baseChainIdDec]}/network`,
       );
     });
+
+    // Sentinel routing via useSentinel flag
+    describe('GET_FEES sentinel routing', () => {
+      it('returns a sentinel URL when useSentinel is true and chain is in SENTINEL_API_BASE_URL_MAP', () => {
+        expect(
+          utils.getAPIRequestURL(APIType.GET_FEES, ChainId.mainnet, true),
+        ).toBe(
+          `${SENTINEL_API_BASE_URL_MAP[ethereumChainIdDec]}/v1/networks/${ethereumChainIdDec}/getFees`,
+        );
+      });
+
+      it('returns the API_BASE_URL when useSentinel is false', () => {
+        expect(
+          utils.getAPIRequestURL(APIType.GET_FEES, ChainId.mainnet, false),
+        ).toBe(`${API_BASE_URL}/networks/${ethereumChainIdDec}/getFees`);
+      });
+
+      it('returns the API_BASE_URL when useSentinel is true but chain is not in SENTINEL_API_BASE_URL_MAP', () => {
+        const unsupportedChainId = '0x539'; // 1337 — local dev chain, not in map
+        const chainIdDec = parseInt(unsupportedChainId, 16);
+        expect(
+          utils.getAPIRequestURL(APIType.GET_FEES, unsupportedChainId, true),
+        ).toBe(`${API_BASE_URL}/networks/${chainIdDec}/getFees`);
+      });
+    });
+
+    describe('SUBMIT_TRANSACTIONS sentinel routing', () => {
+      it('returns a sentinel URL when useSentinel is true and chain is in SENTINEL_API_BASE_URL_MAP', () => {
+        expect(
+          utils.getAPIRequestURL(
+            APIType.SUBMIT_TRANSACTIONS,
+            ChainId.mainnet,
+            true,
+          ),
+        ).toBe(
+          `${SENTINEL_API_BASE_URL_MAP[ethereumChainIdDec]}/v1/networks/${ethereumChainIdDec}/submitTransactions?stxControllerVersion=${packageJson.version}`,
+        );
+      });
+
+      it('returns the API_BASE_URL when useSentinel is false', () => {
+        expect(
+          utils.getAPIRequestURL(
+            APIType.SUBMIT_TRANSACTIONS,
+            ChainId.mainnet,
+            false,
+          ),
+        ).toBe(
+          `${API_BASE_URL}/networks/${ethereumChainIdDec}/submitTransactions?stxControllerVersion=${packageJson.version}`,
+        );
+      });
+
+      it('returns the API_BASE_URL when useSentinel is true but chain is not in SENTINEL_API_BASE_URL_MAP', () => {
+        const unsupportedChainId = '0x539';
+        const chainIdDec = parseInt(unsupportedChainId, 16);
+        expect(
+          utils.getAPIRequestURL(
+            APIType.SUBMIT_TRANSACTIONS,
+            unsupportedChainId,
+            true,
+          ),
+        ).toBe(
+          `${API_BASE_URL}/networks/${chainIdDec}/submitTransactions?stxControllerVersion=${packageJson.version}`,
+        );
+      });
+    });
+
+    describe('CANCEL sentinel routing', () => {
+      it('returns a sentinel URL when useSentinel is true and chain is in SENTINEL_API_BASE_URL_MAP', () => {
+        expect(
+          utils.getAPIRequestURL(APIType.CANCEL, ChainId.mainnet, true),
+        ).toBe(
+          `${SENTINEL_API_BASE_URL_MAP[ethereumChainIdDec]}/v1/networks/${ethereumChainIdDec}/cancel`,
+        );
+      });
+
+      it('returns the API_BASE_URL when useSentinel is false', () => {
+        expect(
+          utils.getAPIRequestURL(APIType.CANCEL, ChainId.mainnet, false),
+        ).toBe(`${API_BASE_URL}/networks/${ethereumChainIdDec}/cancel`);
+      });
+
+      it('returns the API_BASE_URL when useSentinel is true but chain is not in SENTINEL_API_BASE_URL_MAP', () => {
+        const unsupportedChainId = '0x539';
+        const chainIdDec = parseInt(unsupportedChainId, 16);
+        expect(
+          utils.getAPIRequestURL(APIType.CANCEL, unsupportedChainId, true),
+        ).toBe(`${API_BASE_URL}/networks/${chainIdDec}/cancel`);
+      });
+    });
+
+    describe('BATCH_STATUS sentinel routing', () => {
+      it('returns a sentinel URL when useSentinel is true and chain is in SENTINEL_API_BASE_URL_MAP', () => {
+        expect(
+          utils.getAPIRequestURL(APIType.BATCH_STATUS, ChainId.mainnet, true),
+        ).toBe(
+          `${SENTINEL_API_BASE_URL_MAP[ethereumChainIdDec]}/v1/networks/${ethereumChainIdDec}/batchStatus`,
+        );
+      });
+
+      it('returns the API_BASE_URL when useSentinel is false', () => {
+        expect(
+          utils.getAPIRequestURL(APIType.BATCH_STATUS, ChainId.mainnet, false),
+        ).toBe(`${API_BASE_URL}/networks/${ethereumChainIdDec}/batchStatus`);
+      });
+
+      it('returns the API_BASE_URL when useSentinel is true but chain is not in SENTINEL_API_BASE_URL_MAP', () => {
+        const unsupportedChainId = '0x539';
+        const chainIdDec = parseInt(unsupportedChainId, 16);
+        expect(
+          utils.getAPIRequestURL(
+            APIType.BATCH_STATUS,
+            unsupportedChainId,
+            true,
+          ),
+        ).toBe(`${API_BASE_URL}/networks/${chainIdDec}/batchStatus`);
+      });
+    });
   });
 
   describe('isSmartTransactionStatusResolved', () => {
diff --git a/src/utils.ts b/src/utils.ts
index 92b4aee..2e2f61c 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -39,10 +39,17 @@ export const isSmartTransactionStatusResolved = (
 ) => stxStatus === 'uuid_not_found';
 
 // TODO use actual url once API is defined
-export function getAPIRequestURL(apiType: APIType, chainId: string): string {
+export function getAPIRequestURL(
+  apiType: APIType,
+  chainId: string,
+  useSentinel = false,
+): string {
   const chainIdDec = parseInt(chainId, 16);
   switch (apiType) {
     case APIType.GET_FEES: {
+      if (useSentinel && SENTINEL_API_BASE_URL_MAP[chainIdDec]) {
+        return `${SENTINEL_API_BASE_URL_MAP[chainIdDec]}/v1/networks/${chainIdDec}/getFees`;
+      }
       return `${API_BASE_URL}/networks/${chainIdDec}/getFees`;
     }
 
@@ -51,14 +58,23 @@ export function getAPIRequestURL(apiType: APIType, chainId: string): string {
     }
 
     case APIType.SUBMIT_TRANSACTIONS: {
+      if (useSentinel && SENTINEL_API_BASE_URL_MAP[chainIdDec]) {
+        return `${SENTINEL_API_BASE_URL_MAP[chainIdDec]}/v1/networks/${chainIdDec}/submitTransactions?stxControllerVersion=${packageJson.version}`;
+      }
       return `${API_BASE_URL}/networks/${chainIdDec}/submitTransactions?stxControllerVersion=${packageJson.version}`;
     }
 
     case APIType.CANCEL: {
+      if (useSentinel && SENTINEL_API_BASE_URL_MAP[chainIdDec]) {
+        return `${SENTINEL_API_BASE_URL_MAP[chainIdDec]}/v1/networks/${chainIdDec}/cancel`;
+      }
       return `${API_BASE_URL}/networks/${chainIdDec}/cancel`;
     }
 
     case APIType.BATCH_STATUS: {
+      if (useSentinel && SENTINEL_API_BASE_URL_MAP[chainIdDec]) {
+        return `${SENTINEL_API_BASE_URL_MAP[chainIdDec]}/v1/networks/${chainIdDec}/batchStatus`;
+      }
       return `${API_BASE_URL}/networks/${chainIdDec}/batchStatus`;
     }