diff --git a/server/gx-workflow-ls-format2/src/validation/rules/InputTypeValidationRule.ts b/server/gx-workflow-ls-format2/src/validation/rules/InputTypeValidationRule.ts
index 1a759bb..56c6e44 100644
--- a/server/gx-workflow-ls-format2/src/validation/rules/InputTypeValidationRule.ts
+++ b/server/gx-workflow-ls-format2/src/validation/rules/InputTypeValidationRule.ts
@@ -1,5 +1,5 @@
-import { ValidationRule } from "@gxwf/server-common/src/languageTypes";
-import { isCompatibleType } from "@gxwf/server-common/src/utils";
+import { ValidationRule, WorkflowDataType } from "@gxwf/server-common/src/languageTypes";
+import { isCompatibleType, isWorkflowDataType } from "@gxwf/server-common/src/utils";
 import { Diagnostic, DiagnosticSeverity } from "vscode-languageserver-types";
 import { GxFormat2WorkflowDocument } from "../../gxFormat2WorkflowDocument";
 
@@ -16,13 +16,22 @@ export class InputTypeValidationRule implements ValidationRule {
     inputNodes.forEach((input) => {
       const inputName = String(input.keyNode.value);
       const inputType = documentContext.nodeManager.getPropertyValueByName(input, "type") as string;
+
+      if (!isWorkflowDataType(inputType)) {
+        result.push({
+          message: `Input '${inputName}' has an invalid type. Expected a valid workflow data type but found '${inputType}'.`,
+          range: documentContext.nodeManager.getNodeRange(input),
+          severity: this.severity,
+        });
+      }
+
       const defaultValueNode = documentContext.nodeManager.getPropertyNodeByName(input, "default");
       const defaultValue = defaultValueNode?.valueNode?.value;
 
       const defaultValueType = typeof defaultValue;
 
       if (inputType && defaultValue) {
-        const defaultTypeMatchesValue = isCompatibleType(inputType, defaultValueType);
+        const defaultTypeMatchesValue = isCompatibleType(inputType as WorkflowDataType, defaultValueType);
         if (!defaultTypeMatchesValue) {
           result.push({
             message: `Input '${inputName}' default value has invalid type. Expected '${inputType}' but found '${defaultValueType}'.`,
diff --git a/server/packages/server-common/src/utils.ts b/server/packages/server-common/src/utils.ts
index c82ca09..8019952 100644
--- a/server/packages/server-common/src/utils.ts
+++ b/server/packages/server-common/src/utils.ts
@@ -1,3 +1,4 @@
+import { workflowDataTypes } from "../../../../shared/src/requestsDefinitions";
 import { WorkflowDataType } from "./languageTypes";
 
 /**
@@ -32,3 +33,10 @@ export function isCompatibleType(expectedType: WorkflowDataType, actualType: str
   }
   return isCompatible;
 }
+
+export function isWorkflowDataType(type?: string): type is WorkflowDataType {
+  if (!type) {
+    return false;
+  }
+  return type in workflowDataTypes;
+}
diff --git a/shared/src/requestsDefinitions.ts b/shared/src/requestsDefinitions.ts
index 90bd7a3..633b830 100644
--- a/shared/src/requestsDefinitions.ts
+++ b/shared/src/requestsDefinitions.ts
@@ -28,20 +28,33 @@ export interface TargetWorkflowDocumentParams {
   uri: string;
 }
 
-export type WorkflowDataType =
-  | "color" //TODO: this type seems to be missing in format2 schema
-  | "null"
-  | "boolean"
-  | "int"
-  | "long"
-  | "float"
-  | "double"
-  | "string"
-  | "integer"
-  | "text"
-  | "File"
-  | "data"
-  | "collection";
+/**
+ * This contains all the supported data types for workflow inputs.
+ *
+ * **Important**: This definition must be kept in sync with the schema definition.
+ *
+ * Note: Is defined as a const object to be used as a map and to be able to use the keys as a union type.
+ * This way we can maintain a single source of truth for the supported data types and generate WorkflowDataType
+ * type dynamically from it.
+ */
+export const workflowDataTypes = {
+  boolean: true,
+  collection: true,
+  color: true, //TODO: this type seems to be missing in format2 schema
+  data: true,
+  double: true,
+  File: true,
+  float: true,
+  int: true,
+  integer: true,
+  long: true,
+  null: true,
+  string: true,
+  text: true,
+} as const;
+
+// Extract the keys of the object to form the union type
+export type WorkflowDataType = keyof typeof workflowDataTypes;
 
 export interface WorkflowInput {
   name: string;