diff --git a/errorfix/rules/validator.py b/errorfix/rules/validator.py
new file mode 100644
index 0000000..6827af9
--- /dev/null
+++ b/errorfix/rules/validator.py
@@ -0,0 +1,43 @@
+from typing import Dict, Any, List
+import re
+
+
+class RuleValidator:
+    REQUIRED_FIELDS = ['id', 'name', 'pattern', 'fix', 'description']
+    OPTIONAL_FIELDS = ['severity', 'language', 'tool', 'tags', 'priority', 'metadata']
+
+    def validate(self, data: Dict[str, Any]) -> bool:
+        missing = [field for field in self.REQUIRED_FIELDS if field not in data]
+        if missing:
+            raise ValueError(f"Missing required fields: {', '.join(missing)}")
+
+        for field in data:
+            if field not in self.REQUIRED_FIELDS + self.OPTIONAL_FIELDS:
+                raise ValueError(f"Unknown field: {field}")
+
+        self._validate_pattern(data['pattern'])
+        self._validate_severity(data.get('severity', 'error'))
+        self._validate_priority(data.get('priority', 0))
+
+        return True
+
+    def _validate_pattern(self, pattern: str) -> None:
+        if not isinstance(pattern, str):
+            raise ValueError("Pattern must be a string")
+        if not pattern.strip():
+            raise ValueError("Pattern cannot be empty")
+        try:
+            re.compile(pattern)
+        except re.error as e:
+            raise ValueError(f"Invalid regex pattern: {e}")
+
+    def _validate_severity(self, severity: str) -> None:
+        valid_severities = ['error', 'warning', 'info', 'suggestion']
+        if severity not in valid_severities:
+            raise ValueError(f"Invalid severity: {severity}. Must be one of {valid_severities}")
+
+    def _validate_priority(self, priority: int) -> None:
+        if not isinstance(priority, int):
+            raise ValueError("Priority must be an integer")
+        if priority < 0:
+            raise ValueError("Priority must be non-negative")