diff --git a/statemachine/statemachine.asl.json b/statemachine/statemachine.asl.json
new file mode 100644
index 0000000..30fb230
--- /dev/null
+++ b/statemachine/statemachine.asl.json
@@ -0,0 +1,86 @@
+{
+  "Comment": "AWS Lambda Power Tuning state machine",
+  "StartAt": "Initializer",
+  "States": {
+    "Initializer": {
+      "Type": "Task",
+      "Resource": "${initializerArn}",
+      "Next": "Branching",
+      "ResultPath": "$.powerValues",
+      "TimeoutSeconds": ${totalExecutionTimeout},
+      "Catch": [
+        {
+          "ErrorEquals": ["States.ALL"],
+          "Next": "CleanUpOnError",
+          "ResultPath": "$.error"
+        }
+      ]
+    },
+    "Branching": {
+      "Type": "Map",
+      "Next": "Cleaner",
+      "ItemsPath": "$.powerValues",
+      "ResultPath": "$.stats",
+      "ItemSelector": {
+        "input.$": "$",
+        "value.$": "$$.Map.Item.Value"
+      },
+      "MaxConcurrency": 0,
+      "Catch": [
+        {
+          "ErrorEquals": ["States.ALL"],
+          "Next": "CleanUpOnError",
+          "ResultPath": "$.error"
+        }
+      ],
+      "Iterator": {
+        "StartAt": "Executor",
+        "States": {
+          "Executor": {
+            "Type": "Task",
+            "Resource": "${executorArn}",
+            "End": true,
+            "TimeoutSeconds": ${totalExecutionTimeout},
+            "Retry": [{
+                "ErrorEquals": [
+                  "States.ALL"
+                ],
+                "IntervalSeconds": 3,
+                "MaxAttempts": 2
+            }]
+          }
+        }
+      }
+    },
+    "Cleaner": {
+      "Type": "Task",
+      "Next": "Analyzer",
+      "ResultPath": null,
+      "TimeoutSeconds": ${totalExecutionTimeout},
+      "Resource": "${cleanerArn}"
+    },
+    "Analyzer": {
+      "Type": "Task",
+      "Resource": "${analyzerArn}",
+      "ResultPath": "$.analysis",
+      "TimeoutSeconds": 10,
+      "Next": "Optimizer"
+    },
+    "Optimizer": {
+      "Type": "Task",
+      "Resource": "${optimizerArn}",
+      "ResultPath": null,
+      "OutputPath": "$.analysis",
+      "TimeoutSeconds": ${totalExecutionTimeout},
+      "End": true
+    },
+    "CleanUpOnError": {
+      "Type": "Task",
+      "ResultPath": null,
+      "OutputPath": null,
+      "Resource": "${cleanerArn}",
+      "TimeoutSeconds": ${totalExecutionTimeout},
+      "End": true
+    }
+  }
+}
\ No newline at end of file
diff --git a/template.yml b/template.yml
index c79a745..4c240fb 100644
--- a/template.yml
+++ b/template.yml
@@ -15,8 +15,8 @@ Metadata:
     SemanticVersion: 4.3.4
     SourceCodeUrl: https://github.com/alexcasalboni/aws-lambda-power-tuning
 
-Parameters: 
-  PowerValues: 
+Parameters:
+  PowerValues:
     Type: List<Number>
     Default: 128,256,512,1024,1536,3008
     Description: Default RAM values, used only if not provided as execution input (comma-separated).
@@ -267,104 +267,23 @@ Resources:
             Action: sts:AssumeRole
 
   powerTuningStateMachine:
-    Type: AWS::StepFunctions::StateMachine
+    Type: AWS::Serverless::StateMachine
     Properties:
-      StateMachineName: 
+      Name:
         Fn::Join:
           - '-'
           - - !Ref stateMachineNamePrefix
             - !Select [2, !Split ['/', !Ref AWS::StackId]]
-      RoleArn: !GetAtt statemachineRole.Arn
-      DefinitionString:
-        !Sub
-          - '
-            {
-              "Comment": "AWS Lambda Power Tuning state machine",
-              "StartAt": "Initializer",
-              "States": {
-                  "Initializer": {
-                      "Type": "Task",
-                      "Resource": "${initializerArn}",
-                      "Next": "Branching",
-                      "ResultPath": "$.powerValues",
-                      "TimeoutSeconds": ${totalExecutionTimeout},
-                      "Catch": [{
-                        "ErrorEquals": [ "States.ALL" ],
-                        "Next": "CleanUpOnError",
-                        "ResultPath": "$.error"
-                      }]
-                  },
-                  "Branching": {
-                      "Type": "Map",
-                      "Next": "Cleaner",
-                      "ItemsPath": "$.powerValues",
-                      "ResultPath": "$.stats",
-                      "ItemSelector": {
-                        "input.$": "$",
-                        "value.$": "$$.Map.Item.Value"
-                      },
-                      "MaxConcurrency": 0,
-                      "Catch": [{
-                        "ErrorEquals": ["States.ALL"],
-                        "Next": "CleanUpOnError",
-                        "ResultPath": "$.error"
-                      }],
-                      "Iterator": {
-                          "StartAt": "Executor",
-                          "States": {
-                              "Executor": {
-                                  "Type": "Task",
-                                  "Resource": "${executorArn}",
-                                  "End": true,
-                                  "TimeoutSeconds": ${totalExecutionTimeout},
-                                  "Retry": [{
-                                      "ErrorEquals": ["States.ALL"],
-                                      "IntervalSeconds": 3,
-                                      "MaxAttempts": 2
-                                  }]
-                              }
-                          }
-                      }
-                  },
-                  "Cleaner": {
-                      "Type": "Task",
-                      "Next": "Analyzer",
-                      "ResultPath": null,
-                      "TimeoutSeconds": ${totalExecutionTimeout},
-                      "Resource": "${cleanerArn}"
-                  },
-                  "Analyzer": {
-                      "Type": "Task",
-                      "Resource": "${analyzerArn}",
-                      "ResultPath": "$.analysis",
-                      "TimeoutSeconds": 10,
-                      "Next": "Optimizer"
-                  },
-                  "Optimizer": {
-                      "Type": "Task",
-                      "Resource": "${optimizerArn}",
-                      "ResultPath": null,
-                      "OutputPath": "$.analysis",
-                      "TimeoutSeconds": ${totalExecutionTimeout},
-                      "End": true
-                  },
-                  "CleanUpOnError": {
-                      "Type": "Task",
-                      "ResultPath": null,
-                      "OutputPath": null,
-                      "Resource": "${cleanerArn}",
-                      "TimeoutSeconds": ${totalExecutionTimeout},
-                      "End": true
-                  }
-              }
-          }'
-          - initializerArn: !GetAtt initializer.Arn
-            executorArn: !GetAtt executor.Arn
-            cleanerArn: !GetAtt cleaner.Arn
-            analyzerArn: !GetAtt analyzer.Arn
-            optimizerArn: !GetAtt optimizer.Arn
-            totalExecutionTimeout: !Ref totalExecutionTimeout
+      Role: !GetAtt statemachineRole.Arn
+      DefinitionUri: statemachine/statemachine.asl.json
+      DefinitionSubstitutions:
+        initializerArn: !GetAtt initializer.Arn
+        executorArn: !GetAtt executor.Arn
+        cleanerArn: !GetAtt cleaner.Arn
+        analyzerArn: !GetAtt analyzer.Arn
+        optimizerArn: !GetAtt optimizer.Arn
+        totalExecutionTimeout: !Ref totalExecutionTimeout
 
 Outputs:
   StateMachineARN:
-    Value: !Ref powerTuningStateMachine
+    Value: !Ref powerTuningStateMachine
\ No newline at end of file