diff --git a/src/mockapi/core/validator.py b/src/mockapi/core/validator.py
new file mode 100644
index 0000000..8f4d6e9
--- /dev/null
+++ b/src/mockapi/core/validator.py
@@ -0,0 +1,96 @@
+"""OpenAPI Specification Validator."""
+
+from typing import Any, Dict, List, Optional
+
+from openapi_spec_validator import validate_spec
+from openapi_spec_validator.validation.exceptions import OpenAPIValidationError
+
+
+class OpenAPIValidator:
+    """Validates OpenAPI 3.x specifications."""
+
+    def __init__(self, spec: Dict[str, Any]):
+        """Initialize the validator.
+
+        Args:
+            spec: The OpenAPI specification dictionary
+        """
+        self.spec = spec
+        self._validation_errors: List[str] = []
+
+    def validate(self) -> List[str]:
+        """Validate the OpenAPI specification.
+
+        Returns:
+            List of validation error messages (empty if valid)
+        """
+        self._validation_errors = []
+
+        try:
+            validate_spec(self.spec)
+        except OpenAPIValidationError as e:
+            if hasattr(e, "autoblame"):
+                for error in e.autoblame():
+                    message = self._format_validation_error(error)
+                    if message not in self._validation_errors:
+                        self._validation_errors.append(message)
+            else:
+                self._validation_errors.append(str(e))
+        except Exception as e:
+            self._validation_errors.append(f"Validation error: {e}")
+
+        return self._validation_errors
+
+    def _format_validation_error(self, error) -> str:
+        """Format a validation error into a readable message."""
+        if hasattr(error, "message"):
+            return f"{error.message}"
+        return str(error)
+
+    def is_valid(self) -> bool:
+        """Check if the specification is valid.
+
+        Returns:
+            True if valid, False otherwise
+        """
+        return len(self.validate()) == 0
+
+    def get_paths(self) -> List[str]:
+        """Get list of paths in the spec.
+
+        Returns:
+            List of path strings
+        """
+        return list(self.spec.get("paths", {}).keys())
+
+    def get_operations(self, path: str) -> Dict[str, Any]:
+        """Get all operations for a given path.
+
+        Args:
+            path: The path to get operations for
+
+        Returns:
+            Dictionary of method -> operation
+        """
+        path_item = self.spec.get("paths", {}).get(path, {})
+        methods = ["get", "post", "put", "delete", "patch", "options", "head", "trace"]
+        return {m: path_item[m] for m in methods if m in path_item}
+
+    def get_schema(self, schema_name: str) -> Optional[Dict[str, Any]]:
+        """Get a schema by name from components/schemas.
+
+        Args:
+            schema_name: Name of the schema
+
+        Returns:
+            Schema definition or None if not found
+        """
+        return self.spec.get("components", {}).get("schemas", {}).get(schema_name)
+
+    def get_all_schemas(self) -> Dict[str, Any]:
+        """Get all schemas from the spec.
+
+        Returns:
+            Dictionary of schema name -> schema definition
+        """
+        return self.spec.get("components", {}).get("schemas", {})
\ No newline at end of file