diff --git a/src/client/v2/algod/simulateTransaction.ts b/src/client/v2/algod/simulateTransaction.ts
index 0d7a0ace7..1bfcd49c7 100644
--- a/src/client/v2/algod/simulateTransaction.ts
+++ b/src/client/v2/algod/simulateTransaction.ts
@@ -59,16 +59,16 @@ export default class SimulateRawTransactions extends JSONRequest<
     const res = await this.c.post(
       this.path(),
       Buffer.from(this.txnBytesToPost),
-      txHeaders
+      txHeaders,
+      this.query,
+      false
     );
-    return res.body;
+    return this.prepare(res.body);
   }
 
   // eslint-disable-next-line class-methods-use-this
-  prepare(body: Uint8Array) {
-    if (body && body.byteLength > 0) {
-      return encoding.decode(body) as SimulateResponse;
-    }
-    return undefined;
+  prepare(body: Uint8Array): SimulateResponse {
+    const decoded = encoding.decode(body);
+    return SimulateResponse.from_obj_for_encoding(decoded);
   }
 }
diff --git a/src/composer.ts b/src/composer.ts
index a938d7639..99dd2b590 100644
--- a/src/composer.ts
+++ b/src/composer.ts
@@ -635,9 +635,7 @@ export class AtomicTransactionComposer {
     for (const [txnIndex, method] of this.methodCalls) {
       const txID = this.txIDs[txnIndex];
       const pendingInfo =
-        simulateResponse['txn-groups'][0]['txn-results'][txnIndex][
-          'txn-result'
-        ];
+        simulateResponse.txnGroups[0].txnResults[txnIndex].txnResult;
 
       const methodResult: ABIResult = {
         txID,
@@ -649,7 +647,7 @@ export class AtomicTransactionComposer {
         AtomicTransactionComposer.parseMethodResponse(
           method,
           methodResult,
-          pendingInfo
+          pendingInfo.get_obj_for_encoding()
         )
       );
     }
@@ -710,24 +708,29 @@ export class AtomicTransactionComposer {
     for (const [txnIndex, method] of this.methodCalls) {
       const txID = txIDs[txnIndex];
 
-      const methodResult: ABIResult = {
+      let methodResult: ABIResult = {
         txID,
         rawReturnValue: new Uint8Array(),
         method,
       };
 
-      const pendingInfo =
-        txnIndex === firstMethodCallIndex
-          ? confirmedTxnInfo
-          : // eslint-disable-next-line no-await-in-loop
-            await client.pendingTransactionInformation(txID).do();
-      methodResults.push(
-        AtomicTransactionComposer.parseMethodResponse(
+      try {
+        const pendingInfo =
+          txnIndex === firstMethodCallIndex
+            ? confirmedTxnInfo
+            : // eslint-disable-next-line no-await-in-loop
+              await client.pendingTransactionInformation(txID).do();
+
+        methodResult = AtomicTransactionComposer.parseMethodResponse(
           method,
           methodResult,
           pendingInfo
-        )
-      );
+        );
+      } catch (err) {
+        methodResult.decodeError = err;
+      }
+
+      methodResults.push(methodResult);
     }
 
     return {
diff --git a/tests/cucumber/steps/steps.js b/tests/cucumber/steps/steps.js
index ea1230ee5..90e09b13e 100644
--- a/tests/cucumber/steps/steps.js
+++ b/tests/cucumber/steps/steps.js
@@ -4644,7 +4644,7 @@ module.exports = function getSteps(options) {
   Then(
     'the simulation should succeed without any failure message',
     async function () {
-      assert.deepStrictEqual(true, this.simulateResponse['would-succeed']);
+      assert.deepStrictEqual(true, this.simulateResponse.wouldSucceed);
     }
   );
 
@@ -4656,14 +4656,13 @@ module.exports = function getSteps(options) {
       const txnIndexes = stringPath.map((n) => parseInt(n, 10));
       const groupNum = parseInt(txnGroupIndex, 10);
 
-      assert.deepStrictEqual(false, this.simulateResponse['would-succeed']);
+      assert.deepStrictEqual(false, this.simulateResponse.wouldSucceed);
       // Check for missing signature flag
       for (const txnIndex of txnIndexes) {
         assert.deepStrictEqual(
           true,
-          this.simulateResponse['txn-groups'][groupNum]['txn-results'][
-            txnIndex
-          ]['missing-signature']
+          this.simulateResponse.txnGroups[groupNum].txnResults[txnIndex]
+            .missingSignature
         );
       }
     }
@@ -4679,18 +4678,15 @@ module.exports = function getSteps(options) {
       const stringPath = failAt.split(',');
       const failPath = stringPath.map((n) => parseInt(n, 10));
 
-      const failedMessage = this.simulateResponse['txn-groups'][groupNum][
-        'failure-message'
-      ];
-      assert.deepStrictEqual(false, this.simulateResponse['would-succeed']);
+      const failedMessage = this.simulateResponse.txnGroups[groupNum]
+        .failureMessage;
+      assert.deepStrictEqual(false, this.simulateResponse.wouldSucceed);
       const errorContainsString = failedMessage.includes(errorMsg);
       assert.deepStrictEqual(true, errorContainsString);
 
       // Check path array
       // deepStrictEqual fails for firefox tests, so compare array manually.
-      const failedAt = this.simulateResponse['txn-groups'][groupNum][
-        'failed-at'
-      ];
+      const { failedAt } = this.simulateResponse.txnGroups[groupNum];
       assert.strictEqual(failPath.length, failedAt.length);
       for (let i = 0; i < failPath.length; i++) {
         assert.strictEqual(failPath[i], failedAt[i]);