diff --git a/w3b-abi/src/decode.rs b/w3b-abi/src/decode/decode.rs
similarity index 92%
rename from w3b-abi/src/decode.rs
rename to w3b-abi/src/decode/decode.rs
index c441d7a..3e59473 100644
--- a/w3b-abi/src/decode.rs
+++ b/w3b-abi/src/decode/decode.rs
@@ -1,5 +1,3 @@
-use std::{error::Error, fmt};
-
 use w3b_types_abi::{Address, Bytes, Int256, Uint256};
 use w3b_types_core::{
     hex as hex_general,
@@ -8,55 +6,7 @@ use w3b_types_core::{
 
 use crate::{param_type::ParamType, token::Token};
 
-#[derive(PartialEq)]
-pub enum DecodeError {
-    Hex {
-        inner: HexError,
-    },
-    UnexpectedChar {
-        char: char,
-        index: usize,
-        expected: Vec<char>,
-    },
-    InvalidUtf8 {
-        valid_up_to: usize,
-        invalid_size: Option<usize>,
-    },
-}
-
-impl fmt::Debug for DecodeError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            DecodeError::UnexpectedChar {
-                char,
-                index,
-                expected,
-            } => write!(
-                f,
-                "unexpected character {} at index {}, expected {:?}",
-                char, index, expected,
-            ),
-
-            _ => panic!(),
-        }
-    }
-}
-
-impl fmt::Display for DecodeError {
-    #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        <Self as fmt::Debug>::fmt(self, f)
-    }
-}
-
-impl Error for DecodeError {}
-
-impl From<HexError> for DecodeError {
-    #[inline]
-    fn from(inner: HexError) -> Self {
-        DecodeError::Hex { inner }
-    }
-}
+use super::error::DecodeError;
 
 #[inline]
 pub fn decode(input: &str, types: &[ParamType]) -> Result<Vec<Token>, DecodeError> {
diff --git a/w3b-abi/src/decode/error.rs b/w3b-abi/src/decode/error.rs
new file mode 100644
index 0000000..79436bb
--- /dev/null
+++ b/w3b-abi/src/decode/error.rs
@@ -0,0 +1,65 @@
+use std::{error::Error, fmt};
+
+use w3b_types_core::hex::HexError;
+
+#[derive(PartialEq)]
+pub enum DecodeError {
+    Hex {
+        inner: HexError,
+    },
+    UnexpectedChar {
+        char: char,
+        index: usize,
+        expected: Vec<char>,
+    },
+    InvalidUtf8 {
+        valid_up_to: usize,
+        invalid_size: Option<usize>,
+    },
+}
+
+impl fmt::Debug for DecodeError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            DecodeError::Hex { inner } => inner.fmt(f),
+
+            DecodeError::UnexpectedChar {
+                char,
+                index,
+                expected,
+            } => write!(
+                f,
+                "unexpected character {} at index {}, expected {:?}",
+                char, index, expected,
+            ),
+
+            DecodeError::InvalidUtf8 {
+                valid_up_to,
+                invalid_size,
+            } => write!(
+                f,
+                "invalid UTF-8 bytes (valid up to {}{})",
+                valid_up_to,
+                invalid_size
+                    .map(|invalid_size| format!(", invalid size {}", invalid_size))
+                    .unwrap_or_default(),
+            ),
+        }
+    }
+}
+
+impl fmt::Display for DecodeError {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        <Self as fmt::Debug>::fmt(self, f)
+    }
+}
+
+impl Error for DecodeError {}
+
+impl From<HexError> for DecodeError {
+    #[inline]
+    fn from(inner: HexError) -> Self {
+        DecodeError::Hex { inner }
+    }
+}
diff --git a/w3b-abi/src/decode/mod.rs b/w3b-abi/src/decode/mod.rs
new file mode 100644
index 0000000..1ab5716
--- /dev/null
+++ b/w3b-abi/src/decode/mod.rs
@@ -0,0 +1,5 @@
+mod decode;
+mod error;
+
+pub use decode::*;
+pub use error::*;