diff --git a/src/ast.rs b/src/ast.rs
index 542ef09..42fc850 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -1,65 +1,12 @@
 //! Represents the WIT language as a tree. This is the central
 //! representation of the language.
 
-use crate::{interpreter::Instruction, vec1::Vec1};
+use crate::{
+    interpreter::Instruction,
+    types::{InterfaceType, RecordType},
+};
 use std::str;
 
-/// Represents the types supported by WIT.
-#[derive(PartialEq, Debug, Clone)]
-pub enum InterfaceType {
-    /// A 8-bits signed integer.
-    S8,
-
-    /// A 16-bits signed integer.
-    S16,
-
-    /// A 32-bits signed integer.
-    S32,
-
-    /// A 64-bits signed integer.
-    S64,
-
-    /// A 8-bits unsigned integer.
-    U8,
-
-    /// A 16-bits unsigned integer.
-    U16,
-
-    /// A 32-bits unsigned integer.
-    U32,
-
-    /// A 64-bits unsigned integer.
-    U64,
-
-    /// A 32-bits float.
-    F32,
-
-    /// A 64-bits float.
-    F64,
-
-    /// A string.
-    String,
-
-    /// An `any` reference.
-    Anyref,
-
-    /// A 32-bits integer (as defined in WebAssembly core).
-    I32,
-
-    /// A 64-bits integer (as defiend in WebAssembly core).
-    I64,
-
-    /// A record.
-    Record(RecordType),
-}
-
-/// Represents a record type.
-#[derive(PartialEq, Debug, Clone)]
-pub struct RecordType {
-    /// Types representing the fields.
-    pub fields: Vec1<InterfaceType>,
-}
-
 /// Represents the kind of type.
 #[derive(PartialEq, Debug)]
 pub enum TypeKind {
diff --git a/src/decoders/binary.rs b/src/decoders/binary.rs
index 7e0684a..ce0f110 100644
--- a/src/decoders/binary.rs
+++ b/src/decoders/binary.rs
@@ -1,6 +1,6 @@
 //! Parse the WIT binary representation into an [AST](crate::ast).
 
-use crate::{ast::*, interpreter::Instruction, vec1::Vec1};
+use crate::{ast::*, interpreter::Instruction, types::*, vec1::Vec1};
 use nom::{
     error::{make_error, ErrorKind, ParseError},
     Err, IResult,
@@ -445,9 +445,10 @@ fn interfaces<'input, E: ParseError<&'input [u8]>>(
 ///
 /// ```rust
 /// use wasmer_interface_types::{
-///     ast::*,
+///     ast::{Adapter, Export, Implementation, Import, Interfaces, Type},
 ///     decoders::binary::parse,
 ///     interpreter::Instruction,
+///     types::InterfaceType,
 /// };
 ///
 /// let input = &[
diff --git a/src/decoders/wat.rs b/src/decoders/wat.rs
index c0f66ad..eb2f244 100644
--- a/src/decoders/wat.rs
+++ b/src/decoders/wat.rs
@@ -1,6 +1,6 @@
 //! Parse the WIT textual representation into an [AST](crate::ast).
 
-use crate::{ast::*, interpreter::Instruction, vec1::Vec1};
+use crate::{ast::*, interpreter::Instruction, types::*, vec1::Vec1};
 pub use wast::parser::ParseBuffer as Buffer;
 use wast::parser::{self, Cursor, Parse, Parser, Peek, Result};
 
@@ -590,9 +590,10 @@ impl<'a> Parse<'a> for Interfaces<'a> {
 ///
 /// ```rust
 /// use wasmer_interface_types::{
-///     ast::*,
+///     ast::{Adapter, Export, Implementation, Import, Interfaces, Type},
 ///     decoders::wat::{parse, Buffer},
 ///     interpreter::Instruction,
+///     types::InterfaceType,
 /// };
 ///
 /// let input = Buffer::new(
diff --git a/src/encoders/binary.rs b/src/encoders/binary.rs
index 6788bdd..1ad2efe 100644
--- a/src/encoders/binary.rs
+++ b/src/encoders/binary.rs
@@ -1,6 +1,6 @@
 //! Writes the AST into bytes representing WIT with its binary format.
 
-use crate::{ast::*, interpreter::Instruction};
+use crate::{ast::*, interpreter::Instruction, types::*};
 use std::io::{self, Write};
 
 /// A trait for converting a value to bytes.
diff --git a/src/encoders/wat.rs b/src/encoders/wat.rs
index a99adf4..6d58e04 100644
--- a/src/encoders/wat.rs
+++ b/src/encoders/wat.rs
@@ -4,9 +4,10 @@
 //!
 //! ```rust
 //! use wasmer_interface_types::{
-//!     ast::*,
+//!     ast::{Adapter, Export, Implementation, Import, Interfaces, Type},
 //!     encoders::wat::*,
 //!     interpreter::Instruction,
+//!     types::InterfaceType,
 //! };
 //!
 //! let input: String = (&Interfaces {
@@ -54,7 +55,7 @@
 //! assert_eq!(input, output);
 //! ```
 
-use crate::{ast::*, interpreter::Instruction};
+use crate::{ast::*, interpreter::Instruction, types::*};
 use std::string::ToString;
 
 /// Encode an `InterfaceType` into a string.
@@ -346,7 +347,7 @@ impl<'input> ToString for &Interfaces<'input> {
 
 #[cfg(test)]
 mod tests {
-    use crate::{ast::*, interpreter::Instruction};
+    use super::*;
 
     #[test]
     fn test_interface_types() {
diff --git a/src/errors.rs b/src/errors.rs
index fb443ab..0762a24 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -1,10 +1,7 @@
 //! The error module contains all the data structures that represent
 //! an error.
 
-use crate::{
-    ast::{InterfaceType, TypeKind},
-    interpreter::Instruction,
-};
+use crate::{ast::TypeKind, interpreter::Instruction, types::InterfaceType};
 use std::{
     error::Error,
     fmt::{self, Display, Formatter},
diff --git a/src/interpreter/instructions/mod.rs b/src/interpreter/instructions/mod.rs
index 49ab7ca..5b07396 100644
--- a/src/interpreter/instructions/mod.rs
+++ b/src/interpreter/instructions/mod.rs
@@ -164,11 +164,9 @@ where
 #[cfg(test)]
 pub(crate) mod tests {
     use crate::{
-        ast,
-        interpreter::wasm::{
-            self,
-            values::{InterfaceType, InterfaceValue},
-        },
+        ast::*,
+        interpreter::wasm::{self, values::InterfaceValue},
+        types::*,
     };
     use std::{cell::Cell, collections::HashMap, convert::TryInto, ops::Deref, rc::Rc};
 
@@ -265,7 +263,7 @@ pub(crate) mod tests {
         pub(crate) exports: HashMap<String, Export>,
         pub(crate) locals_or_imports: HashMap<usize, LocalImport>,
         pub(crate) memory: Memory,
-        pub(crate) wit_types: Vec<ast::Type>,
+        pub(crate) wit_types: Vec<Type>,
     }
 
     impl Instance {
@@ -322,10 +320,10 @@ pub(crate) mod tests {
                     hashmap
                 },
                 memory: Memory::new(vec![Cell::new(0); 128]),
-                wit_types: vec![ast::Type::Record(ast::RecordType {
+                wit_types: vec![Type::Record(RecordType {
                     fields: vec1![
                         InterfaceType::I32,
-                        InterfaceType::Record(ast::RecordType {
+                        InterfaceType::Record(RecordType {
                             fields: vec1![InterfaceType::String, InterfaceType::F32],
                         }),
                         InterfaceType::I64,
@@ -351,7 +349,7 @@ pub(crate) mod tests {
             Some(&self.memory)
         }
 
-        fn wit_type(&self, index: u32) -> Option<&ast::Type> {
+        fn wit_type(&self, index: u32) -> Option<&Type> {
             self.wit_types.get(index as usize)
         }
     }
diff --git a/src/interpreter/instructions/numbers.rs b/src/interpreter/instructions/numbers.rs
index ad2d38c..ac7012e 100644
--- a/src/interpreter/instructions/numbers.rs
+++ b/src/interpreter/instructions/numbers.rs
@@ -1,7 +1,7 @@
 use crate::{
-    ast::InterfaceType,
     errors::{InstructionError, InstructionErrorKind},
     interpreter::{wasm::values::InterfaceValue, Instruction},
+    types::InterfaceType,
 };
 use std::convert::TryInto;
 
diff --git a/src/interpreter/instructions/records.rs b/src/interpreter/instructions/records.rs
index ad1c58e..a9bbda1 100644
--- a/src/interpreter/instructions/records.rs
+++ b/src/interpreter/instructions/records.rs
@@ -1,5 +1,5 @@
 use crate::{
-    ast::{InterfaceType, RecordType, Type, TypeKind},
+    ast::{Type, TypeKind},
     errors::{InstructionError, InstructionErrorKind},
     interpreter::wasm::values::FlattenInterfaceValueIterator,
     interpreter::{
@@ -7,6 +7,7 @@ use crate::{
         wasm::values::InterfaceValue,
         Instruction,
     },
+    types::{InterfaceType, RecordType},
 };
 use std::collections::VecDeque;
 
@@ -139,7 +140,7 @@ executable_instruction!(
 
 #[cfg(test)]
 mod tests {
-    use crate::ast::{RecordType, Type};
+    use super::*;
 
     test_executable_instruction!(
         test_record_lift =
diff --git a/src/interpreter/instructions/strings.rs b/src/interpreter/instructions/strings.rs
index d84e631..f1223ff 100644
--- a/src/interpreter/instructions/strings.rs
+++ b/src/interpreter/instructions/strings.rs
@@ -1,8 +1,8 @@
 use super::to_native;
 use crate::{
-    ast::InterfaceType,
     errors::{InstructionError, InstructionErrorKind},
     interpreter::{wasm::values::InterfaceValue, Instruction},
+    types::InterfaceType,
 };
 use std::{cell::Cell, convert::TryInto};
 
diff --git a/src/interpreter/wasm/serde/de.rs b/src/interpreter/wasm/serde/de.rs
index 49e166e..efab677 100644
--- a/src/interpreter/wasm/serde/de.rs
+++ b/src/interpreter/wasm/serde/de.rs
@@ -1,8 +1,8 @@
 //! Provides a deserializer from WIT values to Rust value.
 
 use crate::{
-    ast::InterfaceType,
     interpreter::wasm::values::{FlattenInterfaceValueIterator, InterfaceValue},
+    types::InterfaceType,
 };
 use serde::{de, Deserialize};
 use std::{
diff --git a/src/interpreter/wasm/values.rs b/src/interpreter/wasm/values.rs
index 4e93a3b..bd9f6dd 100644
--- a/src/interpreter/wasm/values.rs
+++ b/src/interpreter/wasm/values.rs
@@ -1,6 +1,6 @@
 //! Defines WIT values and associated operations.
 
-pub use crate::ast::{InterfaceType, RecordType};
+pub use crate::types::{InterfaceType, RecordType};
 use crate::{errors::WasmValueNativeCastError, vec1::Vec1};
 use std::{convert::TryFrom, slice::Iter};
 
diff --git a/src/lib.rs b/src/lib.rs
index 1e1c5c2..c376ab0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -51,6 +51,7 @@
 #![doc(html_logo_url = "https://github.com/wasmerio.png")]
 
 pub mod ast;
+pub mod types;
 #[macro_use]
 mod macros;
 pub mod decoders;
diff --git a/src/types.rs b/src/types.rs
new file mode 100644
index 0000000..70a4ca5
--- /dev/null
+++ b/src/types.rs
@@ -0,0 +1,59 @@
+//! This module defines the WIT types.
+
+use crate::vec1::Vec1;
+
+/// Represents the types supported by WIT.
+#[derive(PartialEq, Debug, Clone)]
+pub enum InterfaceType {
+    /// A 8-bits signed integer.
+    S8,
+
+    /// A 16-bits signed integer.
+    S16,
+
+    /// A 32-bits signed integer.
+    S32,
+
+    /// A 64-bits signed integer.
+    S64,
+
+    /// A 8-bits unsigned integer.
+    U8,
+
+    /// A 16-bits unsigned integer.
+    U16,
+
+    /// A 32-bits unsigned integer.
+    U32,
+
+    /// A 64-bits unsigned integer.
+    U64,
+
+    /// A 32-bits float.
+    F32,
+
+    /// A 64-bits float.
+    F64,
+
+    /// A string.
+    String,
+
+    /// An `any` reference.
+    Anyref,
+
+    /// A 32-bits integer (as defined in WebAssembly core).
+    I32,
+
+    /// A 64-bits integer (as defiend in WebAssembly core).
+    I64,
+
+    /// A record.
+    Record(RecordType),
+}
+
+/// Represents a record type.
+#[derive(PartialEq, Debug, Clone)]
+pub struct RecordType {
+    /// Types representing the fields.
+    pub fields: Vec1<InterfaceType>,
+}
diff --git a/tests/binary.rs b/tests/binary.rs
index c9d4709..4e31214 100644
--- a/tests/binary.rs
+++ b/tests/binary.rs
@@ -1,5 +1,5 @@
 use wasmer_interface_types::{
-    ast::*, decoders::binary::parse, encoders::binary::ToBytes, interpreter::Instruction,
+    ast::*, decoders::binary::parse, encoders::binary::ToBytes, interpreter::Instruction, types::*,
     vec1::Vec1,
 };