diff --git a/src-tauri/src/domain/markdown.rs b/src-tauri/src/domain/markdown.rs
new file mode 100644
index 0000000..098e9a3
--- /dev/null
+++ b/src-tauri/src/domain/markdown.rs
@@ -0,0 +1,27 @@
+#[allow(dead_code)]
+pub trait MarkdownRenderer: Send + Sync {
+    fn render(&self, content: &str) -> String;
+}
+
+#[derive(Default)]
+#[allow(dead_code)]
+pub struct RenderOptions {
+    pub tables: bool,
+    pub strikethrough: bool,
+    pub autolink: bool,
+    pub tasklist: bool,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn render_options_default_all_false() {
+        let opts = RenderOptions::default();
+        assert!(!opts.tables);
+        assert!(!opts.strikethrough);
+        assert!(!opts.autolink);
+        assert!(!opts.tasklist);
+    }
+}
diff --git a/src-tauri/src/domain/mod.rs b/src-tauri/src/domain/mod.rs
new file mode 100644
index 0000000..307c3b5
--- /dev/null
+++ b/src-tauri/src/domain/mod.rs
@@ -0,0 +1,4 @@
+mod markdown;
+
+#[allow(unused_imports)]
+pub use markdown::{MarkdownRenderer, RenderOptions};
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 38b09ab..99a625f 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -1,4 +1,5 @@
 mod core;
+mod domain;
 mod watcher;
 
 use std::sync::Mutex;