diff --git a/src/indexer/base.py b/src/indexer/base.py
new file mode 100644
index 0000000..4a040ee
--- /dev/null
+++ b/src/indexer/base.py
@@ -0,0 +1,81 @@
+"""Base indexer interface for documentation parsing."""
+
+from abc import ABC, abstractmethod
+from pathlib import Path
+from typing import Generator, List
+
+from src.models.document import Document, SourceType
+
+
+class BaseIndexer(ABC):
+    """Abstract base class for document indexers."""
+
+    source_type: SourceType
+
+    @abstractmethod
+    def index(self, path: Path, recursive: bool = False) -> List[Document]:
+        """Index documents from the given path.
+
+        Args:
+            path: Path to file or directory to index
+            recursive: Whether to search directories recursively
+
+        Returns:
+            List of indexed Document objects
+        """
+        pass
+
+    @abstractmethod
+    def get_documents(self) -> List[Document]:
+        """Get all indexed documents.
+
+        Returns:
+            List of Document objects
+        """
+        pass
+
+    def _find_files(self, path: Path, recursive: bool = False) -> Generator[Path, None, None]:
+        """Find files to index in the given path.
+
+        Args:
+            path: Path to file or directory
+            recursive: Whether to search recursively
+
+        Yields:
+            Path objects for each file found
+        """
+        if path.is_file():
+            if self._is_supported_file(path):
+                yield path
+        elif path.is_dir():
+            pattern = "**/*" if recursive else "*"
+            for file_path in path.glob(pattern):
+                if file_path.is_file() and self._is_supported_file(file_path):
+                    yield file_path
+
+    @abstractmethod
+    def _is_supported_file(self, path: Path) -> bool:
+        """Check if the file is supported by this indexer.
+
+        Args:
+            path: Path to the file
+
+        Returns:
+            True if the file is supported
+        """
+        pass
+
+    def _generate_id(self, file_path: Path, suffix: str = "") -> str:
+        """Generate a unique document ID.
+
+        Args:
+            file_path: Path to the source file
+            suffix: Optional suffix to add to the ID
+
+        Returns:
+            Unique document ID string
+        """
+        stem = file_path.stem.replace(" ", "_").lower()
+        if suffix:
+            return f"{stem}_{suffix}"
+        return stem