diff --git a/bindings/wasm/lib.rs b/bindings/wasm/lib.rs
index 03ce51bdd..c827f27c4 100644
--- a/bindings/wasm/lib.rs
+++ b/bindings/wasm/lib.rs
@@ -8,8 +8,16 @@ pub struct Database {
 #[wasm_bindgen]
 impl Database {
     pub fn open(path: &str) -> Database {
-        let io = lig_core::IO::new().unwrap();
-        let inner = lig_core::Database::open(io, path).unwrap();
+        let io = IO {};
+        let inner = lig_core::Database::open(&io, path).unwrap();
         Database { _inner: inner }
     }
 }
+
+struct IO {}
+
+impl lig_core::IO for IO {
+    fn open(&self, _path: &str) -> anyhow::Result<lig_core::PageSource> {
+        todo!();
+    }
+}
diff --git a/cli/main.rs b/cli/main.rs
index bbd014677..8acebfaad 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -1,6 +1,6 @@
 use clap::{Parser, ValueEnum};
 use cli_table::{Cell, Table};
-use lig_core::{Database, Value, IO};
+use lig_core::{Database, Value};
 use rustyline::{error::ReadlineError, DefaultEditor};
 use std::path::PathBuf;
 
@@ -29,8 +29,8 @@ struct Opts {
 
 fn main() -> anyhow::Result<()> {
     let opts = Opts::parse();
-    let io = IO::new()?;
-    let db = Database::open(io, opts.database.to_str().unwrap())?;
+    let io = lig_core::default_io()?;
+    let db = Database::open(&io, opts.database.to_str().unwrap())?;
     let conn = db.connect();
     let mut rl = DefaultEditor::new()?;
     let home = dirs::home_dir().unwrap();
diff --git a/core/io/darwin.rs b/core/io/darwin.rs
index 31db98aea..b1670ade8 100644
--- a/core/io/darwin.rs
+++ b/core/io/darwin.rs
@@ -1,12 +1,21 @@
+use crate::{PageSource, IO};
 use anyhow::{Ok, Result};
 use std::cell::RefCell;
 use std::io::{Read, Seek};
+use std::sync::Arc;
 
-pub(crate) struct Loop {}
+pub(crate) struct DarwinIO {}
 
-impl Loop {
+impl IO for DarwinIO {
+    fn open(&self, path: &str) -> Result<PageSource> {
+        let file = self.open_file(path)?;
+        Ok(PageSource { io: Arc::new(file) })
+    }
+}
+
+impl DarwinIO {
     pub(crate) fn new() -> Result<Self> {
-        Ok(Loop {})
+        Ok(DarwinIO {})
     }
 
     pub(crate) fn open_file(&self, path: &str) -> Result<File> {
diff --git a/core/io/linux.rs b/core/io/linux.rs
index b25e0ecb8..6565f3981 100644
--- a/core/io/linux.rs
+++ b/core/io/linux.rs
@@ -1,16 +1,25 @@
+use crate::io::{PageSource, IO};
 use anyhow::Result;
 use std::cell::RefCell;
 use std::os::unix::io::AsRawFd;
 use std::rc::Rc;
+use std::sync::Arc;
 
-pub(crate) struct Loop {
+pub(crate) struct LinuxIO {
     ring: Rc<RefCell<io_uring::IoUring>>,
 }
 
-impl Loop {
+impl IO for LinuxIO {
+    fn open(&self, path: &str) -> Result<PageSource> {
+        let file = self.open_file(path)?;
+        Ok(PageSource { io: Arc::new(file) })
+    }
+}
+
+impl LinuxIO {
     pub(crate) fn new() -> Result<Self> {
         let ring = io_uring::IoUring::new(8)?;
-        Ok(Loop {
+        Ok(LinuxIO {
             ring: Rc::new(RefCell::new(ring)),
         })
     }
diff --git a/core/io/mod.rs b/core/io/mod.rs
index bacefe398..c55a7eb85 100644
--- a/core/io/mod.rs
+++ b/core/io/mod.rs
@@ -1,75 +1,24 @@
-use anyhow::{Ok, Result};
+use anyhow::Result;
 use std::sync::Arc;
 
-#[cfg(all(feature = "fs", target_os = "linux"))]
+#[cfg(target_os = "linux")]
 mod linux;
 
-#[cfg(feature = "fs")]
+#[cfg(target_os = "macos")]
 mod darwin;
 
-/// I/O access method
-enum IOMethod {
-    #[cfg(not(feature = "fs"))]
-    Memory,
-
-    #[cfg(feature = "fs")]
-    Sync { io: darwin::Loop },
-
-    #[cfg(target_os = "linux")]
-    IoUring { io: linux::Loop },
+pub trait IO {
+    fn open(&self, path: &str) -> Result<PageSource>;
 }
 
-/// I/O access interface.
-pub struct IO {
-    io_method: IOMethod,
+#[cfg(target_os = "linux")]
+pub fn default_io() -> Result<impl IO> {
+    Ok(linux::LinuxIO::new()?)
 }
 
-impl IO {
-    #[cfg(all(feature = "fs", target_os = "linux"))]
-    pub fn new() -> Result<Self> {
-        Ok(IO {
-            io_method: IOMethod::IoUring {
-                io: linux::Loop::new()?,
-            },
-        })
-    }
-
-    #[cfg(all(feature = "fs", target_os = "macos"))]
-    pub fn new() -> Result<Self> {
-        Ok(IO {
-            io_method: IOMethod::Sync {
-                io: darwin::Loop::new()?,
-            },
-        })
-    }
-
-    #[cfg(not(feature = "fs"))]
-    pub fn new() -> Result<Self> {
-        Ok(IO {
-            io_method: IOMethod::Memory,
-        })
-    }
-}
-
-impl IO {
-    pub fn open(&self, path: &str) -> Result<PageSource> {
-        match &self.io_method {
-            #[cfg(feature = "fs")]
-            IOMethod::Sync { io } => {
-                let io = Arc::new(io.open_file(path)?);
-                Ok(PageSource { io })
-            }
-            #[cfg(all(feature = "fs", target_os = "linux"))]
-            IOMethod::IoUring { io } => {
-                let io = Arc::new(io.open_file(path)?);
-                Ok(PageSource { io })
-            }
-            #[cfg(not(feature = "fs"))]
-            IOMethod::Memory => {
-                todo!();
-            }
-        }
-    }
+#[cfg(target_os = "macos")]
+pub fn default_io() -> Result<impl IO> {
+    Ok(darwin::DarwinIO::new()?)
 }
 
 pub struct PageSource {
diff --git a/core/lib.rs b/core/lib.rs
index f0a335a87..97e8fe02f 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -20,6 +20,7 @@ use schema::Schema;
 use sqlite3_parser::{ast::Cmd, lexer::sql::Parser};
 use std::sync::Arc;
 
+pub use io::default_io;
 pub use io::{PageSource, IO};
 pub use types::Value;
 
@@ -29,8 +30,8 @@ pub struct Database {
 }
 
 impl Database {
-    pub fn open(io: IO, path: &str) -> Result<Database> {
-        let pager = Arc::new(Pager::open(&io, path)?);
+    pub fn open(io: &impl IO, path: &str) -> Result<Database> {
+        let pager = Arc::new(Pager::open(io, path)?);
         let bootstrap_schema = Arc::new(Schema::new());
         let conn = Connection {
             pager: pager.clone(),
diff --git a/core/pager.rs b/core/pager.rs
index 0a5cf62be..5ffce3b42 100644
--- a/core/pager.rs
+++ b/core/pager.rs
@@ -13,7 +13,7 @@ pub struct Pager {
 }
 
 impl Pager {
-    pub fn open(io: &IO, path: &str) -> anyhow::Result<Self> {
+    pub fn open(io: &impl IO, path: &str) -> anyhow::Result<Self> {
         let database = io.open(path)?;
         let db_header = sqlite3_ondisk::read_database_header(&database)?;
         let page_size = db_header.page_size as usize;