diff --git a/Cargo.toml b/Cargo.toml
index 51aef1b7..1ab47fe7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ authors = ["Sergey Shandar"]
 
 [dependencies]
 libc = "0.2.149"
+io-trait = "0.1.1"
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3.37"
diff --git a/src/app.rs b/src/app.rs
index 3a045928..f0a3b08b 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -1,16 +1,16 @@
 use std::io::{self, Read, Write};
 
+use io_trait::{DirEntry, Io, Metadata};
+
 use crate::{
     base32::{StrEx, ToBase32},
     file_table::{FileTable, CDT0, PARTS, ROOTS},
-    io::{DirEntry, Io},
     level_storage::LevelStorage,
     state::{mb, progress, State},
     storage::{Null, Storage},
     table::{Table, Type},
     tree::Tree,
     u224::U224,
-    Metadata,
 };
 
 trait ResultEx {
@@ -153,6 +153,7 @@ pub fn run(io: &impl Io) -> Result<(), String> {
 
 #[cfg(test)]
 mod test {
+    use io_trait::Io;
     use wasm_bindgen_test::wasm_bindgen_test;
 
     use crate::{
@@ -161,7 +162,6 @@ mod test {
         sha224::{compress, compress_one},
         u256::{to_u224, U256},
         virtual_io::VirtualIo,
-        Io,
     };
 
     #[wasm_bindgen_test]
diff --git a/src/file_table.rs b/src/file_table.rs
index 242ebf5b..0421e7b4 100644
--- a/src/file_table.rs
+++ b/src/file_table.rs
@@ -1,10 +1,11 @@
 use std::io;
 
+use io_trait::Io;
+
 use crate::{
     base32::ToBase32,
     table::{Table, Type},
     u224::U224,
-    Io,
 };
 
 pub struct FileTable<'a, T: Io>(pub &'a T);
diff --git a/src/io.rs b/src/io.rs
index 5fdcb3b8..59cd5cb8 100644
--- a/src/io.rs
+++ b/src/io.rs
@@ -1,92 +1,10 @@
-use std::{
-    ffi::CStr,
-    fmt,
-    io::{self, Read, Write},
-};
-
-#[allow(clippy::len_without_is_empty)]
-pub trait Metadata {
-    fn len(&self) -> u64;
-    fn is_dir(&self) -> bool;
-}
-
-pub trait DirEntry {
-    type Metadata: Metadata;
-    fn path(&self) -> String;
-    fn metadata(&self) -> io::Result<Self::Metadata>;
-}
-
-pub trait Io {
-    type Args: Iterator<Item = String>;
-    type File: Read + Write + fmt::Debug;
-    type Stdout: Write;
-    type Metadata: Metadata;
-    type DirEntry: DirEntry;
-    fn args(&self) -> Self::Args;
-    fn stdout(&self) -> Self::Stdout;
-    fn metadata(&self, path: &str) -> io::Result<Self::Metadata>;
-    fn create_dir(&self, path: &str) -> io::Result<()>;
-    fn create(&self, path: &str) -> io::Result<Self::File>;
-    fn open(&self, path: &str) -> io::Result<Self::File>;
-    fn read(&self, path: &str) -> io::Result<Vec<u8>> {
-        let mut file = self.open(path)?;
-        let mut result = Vec::default();
-        file.read_to_end(&mut result)?;
-        Ok(result)
-    }
-    fn read_dir(&self, path: &str) -> io::Result<Vec<Self::DirEntry>>;
-    fn read_to_string(&self, path: &str) -> io::Result<String> {
-        let mut file = self.open(path)?;
-        let mut result = String::default();
-        file.read_to_string(&mut result)?;
-        Ok(result)
-    }
-    fn write(&self, path: &str, data: &[u8]) -> io::Result<()> {
-        let mut file = self.create(path)?;
-        file.write_all(data)?;
-        Ok(())
-    }
-    fn create_dir_recursively(&self, path: &str) -> io::Result<()> {
-        let mut x = String::default();
-        let mut e = Ok(());
-        for i in path.split('/') {
-            x += i;
-            e = self.create_dir(&x);
-            x += "/";
-        }
-        e
-    }
-    fn write_recursively(&self, path: &str, data: &[u8]) -> io::Result<()> {
-        let e = self.write(path, data);
-        if let Err(er) = e {
-            return if let Some((p, _)) = path.rsplit_once('/') {
-                self.create_dir_recursively(p)?;
-                self.write(path, data)
-            } else {
-                Err(er)
-            };
-        }
-        Ok(())
-    }
-    fn read_dir_type(&self, path: &str, is_dir: bool) -> io::Result<Vec<Self::DirEntry>> {
-        let mut result = Vec::default();
-        for i in self.read_dir(path)? {
-            if i.metadata()?.is_dir() == is_dir {
-                result.push(i);
-            }
-        }
-        Ok(result)
-    }
-}
-
 #[cfg(test)]
 mod test {
+    use io_trait::Io;
     use wasm_bindgen_test::wasm_bindgen_test;
 
     use crate::virtual_io::VirtualIo;
 
-    use super::Io;
-
     #[wasm_bindgen_test]
     #[test]
     fn test() {
diff --git a/src/lib.rs b/src/lib.rs
index 06e19017..225dbecc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -34,5 +34,4 @@ mod static_assert;
 mod virtual_io;
 
 pub use app::run;
-pub use io::{Io, Metadata};
 pub use real_io::RealIo;
diff --git a/src/real_io.rs b/src/real_io.rs
index 5313efdc..45af1068 100644
--- a/src/real_io.rs
+++ b/src/real_io.rs
@@ -6,26 +6,7 @@ use std::{
     io::{self, Stdout},
 };
 
-use crate::{io::DirEntry, Io, Metadata};
-
-impl Metadata for fs::Metadata {
-    fn len(&self) -> u64 {
-        self.len()
-    }
-    fn is_dir(&self) -> bool {
-        self.is_dir()
-    }
-}
-
-impl DirEntry for fs::DirEntry {
-    type Metadata = fs::Metadata;
-    fn path(&self) -> String {
-        self.path().to_str().unwrap().to_string()
-    }
-    fn metadata(&self) -> io::Result<Self::Metadata> {
-        self.metadata()
-    }
-}
+use io_trait::Io;
 
 #[derive(Default)]
 pub struct RealIo();
diff --git a/src/virtual_io.rs b/src/virtual_io.rs
index 18a9744f..c21bca43 100644
--- a/src/virtual_io.rs
+++ b/src/virtual_io.rs
@@ -7,7 +7,7 @@ use std::{
     vec,
 };
 
-use crate::io::Io;
+use io_trait::Io;
 
 #[derive(Debug, Clone)]
 pub struct Metadata {
@@ -15,7 +15,7 @@ pub struct Metadata {
     is_dir: bool,
 }
 
-impl crate::io::Metadata for Metadata {
+impl io_trait::Metadata for Metadata {
     fn len(&self) -> u64 {
         self.len
     }
@@ -100,7 +100,7 @@ pub struct DirEntry {
     metadata: Metadata,
 }
 
-impl crate::io::DirEntry for DirEntry {
+impl io_trait::DirEntry for DirEntry {
     type Metadata = Metadata;
     fn path(&self) -> String {
         self.path.clone()