diff --git a/src/Hacknet/HacknetNode.ts b/src/Hacknet/HacknetNode.ts
index 4982b606b..5cb950232 100644
--- a/src/Hacknet/HacknetNode.ts
+++ b/src/Hacknet/HacknetNode.ts
@@ -18,8 +18,18 @@ import { HacknetNodeConstants } from "./data/Constants";
 
 import { dialogBoxCreate } from "../ui/React/DialogBox";
 import { Generic_fromJSON, Generic_toJSON, Reviver } from "../utils/JSONReviver";
+import { ObjectValidator, minMax } from "../utils/Validator";
 
 export class HacknetNode implements IHacknetNode {
+
+  static validationData: ObjectValidator<HacknetNode> = {
+    cores: minMax(1, 1, HacknetNodeConstants.MaxCores),
+    level: minMax(1, 1, HacknetNodeConstants.MaxLevel),
+    ram: minMax(1, 1, HacknetNodeConstants.MaxRam),
+    onlineTimeSeconds: minMax(0, 0, Infinity),
+    totalMoneyGenerated: minMax(0, 0, Infinity)
+  }
+
   // Node's number of cores
   cores = 1;
 
diff --git a/src/utils/JSONReviver.ts b/src/utils/JSONReviver.ts
index eeb832cec..5b7447d09 100644
--- a/src/utils/JSONReviver.ts
+++ b/src/utils/JSONReviver.ts
@@ -1,5 +1,7 @@
 /* Generic Reviver, toJSON, and fromJSON functions used for saving and loading objects */
 
+import { validateObject } from "./Validator";
+
 interface IReviverValue {
   ctor: string;
   data: any;
@@ -26,7 +28,11 @@ export function Reviver(key: string, value: IReviverValue | null): any {
     const ctor = Reviver.constructors[value.ctor];
 
     if (typeof ctor === "function" && typeof ctor.fromJSON === "function") {
-      return ctor.fromJSON(value);
+      const obj = ctor.fromJSON(value);
+      if (ctor.validationData !== undefined) {
+        validateObject(obj, ctor.validationData);
+      }
+      return obj;
     }
   }
   return value;
diff --git a/src/utils/Validator.ts b/src/utils/Validator.ts
new file mode 100644
index 000000000..21daba59e
--- /dev/null
+++ b/src/utils/Validator.ts
@@ -0,0 +1,78 @@
+export type ObjectValidator<T> = {
+  [key in keyof T]?: ParameterValidator<T, keyof T>;
+}
+
+interface ParameterValidatorObject<Type, Key extends keyof Type> {
+  default?: any;
+  min?: number;
+  max?: number;
+  func?: (obj: Type, validator: ObjectValidator<Type>, key: Key) => void;
+}
+type ParameterValidatorFunction<Type, Key extends keyof Type> = (obj: Type, key: Key) => void;
+type ParameterValidator<Type, Key extends keyof Type> = ParameterValidatorObject<Type, Key> | ParameterValidatorFunction<Type, Key>
+
+export function validateObject<Type extends Record<string, unknown>, Key extends keyof Type>(obj: Type, validator: ObjectValidator<Type>): void {
+  for (const key of Object.keys(validator) as Key[]) {
+    const paramValidator = validator[key];
+    if (paramValidator !== undefined)  {
+      if (typeof paramValidator === 'function') {
+        paramValidator(obj, key);
+      } else {
+        if (paramValidator.func !== undefined) {
+          paramValidator.func(obj, validator, key);
+        } else {
+          if ((typeof obj[key]) !== (typeof paramValidator.default)) {
+            obj[key] = paramValidator.default
+          }
+          if (typeof obj[key] === 'number' && paramValidator.min !== undefined) {
+            if (obj[key] < paramValidator.min) obj[key] = paramValidator.min as Type[Key];
+          }
+          if (typeof obj[key] === 'number' && paramValidator.max !== undefined) {
+            if (obj[key] > paramValidator.max) obj[key] = paramValidator.max as Type[Key];
+          }
+        }
+      }
+    }
+  }
+}
+
+export function minMax<Type, Key extends keyof Type>(def: number, min: number, max: number): (obj: Type, key: Key & keyof Type) => void {
+  return (obj, key) => {
+    if (typeof obj[key] !== 'number') {
+      obj[key] = def as unknown as Type[Key];
+      return;
+    }
+    if ((obj[key] as unknown as number) < min) {
+      obj[key] = min as unknown as Type[Key];
+    }
+    if ((obj[key] as unknown as number) > max) {
+      obj[key] = max as unknown as Type[Key];
+    }
+  };
+}
+
+export function oneOf<Type, Key extends keyof Type, Value>(def: Value, options: Value[]): (obj: Type, key: Key & keyof Type) => void {
+  return (obj, key) => {
+    if (typeof obj[key] !== typeof def) {
+      obj[key] = def as unknown as Type[Key];
+      return;
+    }
+    if (!options.includes(obj[key] as unknown as Value)) {
+      obj[key] = def as unknown as Type[Key];
+    }
+  };
+}
+
+export function subsetOf<Type, Key extends keyof Type, Value>(options: Value[]): (obj: Type, key: Key & keyof Type) => void {
+  return (obj, key) => {
+    if (typeof obj[key] !== 'object' || !Array.isArray(obj[key])) {
+      obj[key] = [] as unknown as Type[Key];
+      return;
+    }
+    const validValues: Value[] = [];
+    for (const value of obj[key] as unknown as Value[]) {
+      if (options.includes(value)) validValues.push(value);
+    }
+    obj[key] = validValues as unknown as Type[Key];
+  };
+}
\ No newline at end of file