diff --git a/Cargo.lock b/Cargo.lock
index 4ca9fedf9..a08224c12 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -493,6 +493,12 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "indextree"
+version = "4.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497f036ac2fae75c34224648a77802e5dd4e9cfb56f4713ab6b12b7160a0523b"
+
 [[package]]
 name = "io-lifetimes"
 version = "1.0.5"
@@ -838,6 +844,14 @@ dependencies = [
  "oxc_parser",
 ]
 
+[[package]]
+name = "oxc_semantic"
+version = "0.0.0"
+dependencies = [
+ "indextree",
+ "oxc_ast",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.2.0"
diff --git a/Cargo.toml b/Cargo.toml
index a2ed42e4d..cd4adadfb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,7 @@ serde_json = "1.0.93"
 thiserror = "1.0.38"
 jemallocator = "0.5.0"
 clap = "4.1.4"
+indextree = "4.5.0"
 
 [profile.release]
 lto = "fat"
diff --git a/crates/oxc_ast/src/lib.rs b/crates/oxc_ast/src/lib.rs
index ff09ad1c0..86477b13b 100644
--- a/crates/oxc_ast/src/lib.rs
+++ b/crates/oxc_ast/src/lib.rs
@@ -15,6 +15,7 @@ pub mod span;
 pub mod syntax_directed_operations;
 pub mod visit;
 
+pub use ast_kind::AstKind;
 pub use num_bigint::BigUint;
 
 pub use crate::ast_builder::*;
diff --git a/crates/oxc_semantic/Cargo.toml b/crates/oxc_semantic/Cargo.toml
new file mode 100644
index 000000000..3c2e3b4ec
--- /dev/null
+++ b/crates/oxc_semantic/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "oxc_semantic"
+authors.workspace = true
+description.workspace = true
+edition.workspace = true
+homepage.workspace = true
+keywords.workspace = true
+license.workspace = true
+repository.workspace = true
+version.workspace = true
+
+[dependencies]
+oxc_ast = { path = "../oxc_ast" }
+
+indextree = { workspace = true }
diff --git a/crates/oxc_semantic/src/Cargo.toml b/crates/oxc_semantic/src/Cargo.toml
new file mode 100644
index 000000000..b96ce8b96
--- /dev/null
+++ b/crates/oxc_semantic/src/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "oxc_printer"
+authors.workspace = true
+description.workspace = true
+edition.workspace = true
+homepage.workspace = true
+keywords.workspace = true
+license.workspace = true
+repository.workspace = true
+version.workspace = true
diff --git a/crates/oxc_semantic/src/builder.rs b/crates/oxc_semantic/src/builder.rs
new file mode 100644
index 000000000..f30830fb7
--- /dev/null
+++ b/crates/oxc_semantic/src/builder.rs
@@ -0,0 +1,56 @@
+//! Semantic Builder
+//! This builds:
+//!   * The untyped and flattened ast nodes into an indextree
+
+use oxc_ast::{ast::Program, visit::Visit, AstKind};
+
+use crate::{
+    node::{AstNodeId, AstNodes, SemanticNode},
+    Semantic,
+};
+
+#[derive(Debug)]
+pub struct SemanticBuilder<'a> {
+    nodes: AstNodes<'a>,
+    current_node_id: AstNodeId,
+}
+
+impl<'a> SemanticBuilder<'a> {
+    #[must_use]
+    #[allow(clippy::new_without_default)]
+    pub fn new() -> Self {
+        let mut nodes = AstNodes::default();
+        let semantic_node = SemanticNode::new(AstKind::Root);
+        let current_node_id = nodes.new_node(semantic_node).into();
+        Self { nodes, current_node_id }
+    }
+
+    #[must_use]
+    pub fn build(mut self, program: &'a Program<'a>) -> Semantic<'a> {
+        // AST pass
+        self.visit_program(program);
+        Semantic { nodes: self.nodes }
+    }
+
+    fn create_ast_node(&mut self, kind: AstKind<'a>) {
+        let ast_node = SemanticNode::new(kind);
+        let node_id = self.nodes.new_node(ast_node);
+        self.current_node_id.append(node_id, &mut self.nodes);
+        self.current_node_id = node_id.into();
+    }
+
+    fn pop_ast_node(&mut self) {
+        self.current_node_id =
+            self.nodes[self.current_node_id.indextree_id()].parent().unwrap().into();
+    }
+}
+
+impl<'a> Visit<'a> for SemanticBuilder<'a> {
+    fn enter_node(&mut self, kind: AstKind<'a>) {
+        self.create_ast_node(kind);
+    }
+
+    fn leave_node(&mut self, _kind: AstKind<'a>) {
+        self.pop_ast_node();
+    }
+}
diff --git a/crates/oxc_semantic/src/lib.rs b/crates/oxc_semantic/src/lib.rs
new file mode 100644
index 000000000..ddfaa1374
--- /dev/null
+++ b/crates/oxc_semantic/src/lib.rs
@@ -0,0 +1,16 @@
+mod builder;
+mod node;
+
+pub use builder::SemanticBuilder;
+use node::AstNodes;
+
+pub struct Semantic<'a> {
+    nodes: AstNodes<'a>,
+}
+
+impl<'a> Semantic<'a> {
+    #[must_use]
+    pub const fn nodes(&self) -> &AstNodes<'a> {
+        &self.nodes
+    }
+}
diff --git a/crates/oxc_semantic/src/node/id.rs b/crates/oxc_semantic/src/node/id.rs
new file mode 100644
index 000000000..ede3a7934
--- /dev/null
+++ b/crates/oxc_semantic/src/node/id.rs
@@ -0,0 +1,38 @@
+use std::ops::Deref;
+
+use indextree::NodeId;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct AstNodeId(NodeId);
+
+impl AstNodeId {
+    #[must_use]
+    pub const fn new(node_id: NodeId) -> Self {
+        Self(node_id)
+    }
+
+    #[must_use]
+    pub const fn indextree_id(&self) -> NodeId {
+        self.0
+    }
+}
+
+impl From<NodeId> for AstNodeId {
+    fn from(node_id: NodeId) -> Self {
+        Self(node_id)
+    }
+}
+
+impl From<AstNodeId> for NodeId {
+    fn from(ast_node_id: AstNodeId) -> Self {
+        ast_node_id.indextree_id()
+    }
+}
+
+impl Deref for AstNodeId {
+    type Target = NodeId;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
diff --git a/crates/oxc_semantic/src/node/mod.rs b/crates/oxc_semantic/src/node/mod.rs
new file mode 100644
index 000000000..73edd9aeb
--- /dev/null
+++ b/crates/oxc_semantic/src/node/mod.rs
@@ -0,0 +1,27 @@
+mod id;
+mod tree;
+
+pub use id::AstNodeId;
+use oxc_ast::AstKind;
+pub use tree::AstNodes;
+
+/// Indextree node containing a semantic node
+pub type AstNode<'a> = indextree::Node<SemanticNode<'a>>;
+
+/// Semantic node contains all the semantic information about an ast node.
+#[derive(Debug, Clone, Copy)]
+pub struct SemanticNode<'a> {
+    /// A pointer to the ast node, which resides in the `bumpalo` memory arena.
+    kind: AstKind<'a>,
+}
+
+impl<'a> SemanticNode<'a> {
+    #[must_use]
+    pub const fn new(kind: AstKind<'a>) -> Self {
+        Self { kind }
+    }
+
+    pub const fn kind(&self) -> AstKind<'a> {
+        self.kind
+    }
+}
diff --git a/crates/oxc_semantic/src/node/tree.rs b/crates/oxc_semantic/src/node/tree.rs
new file mode 100644
index 000000000..55d8982e4
--- /dev/null
+++ b/crates/oxc_semantic/src/node/tree.rs
@@ -0,0 +1,56 @@
+use std::ops::{Deref, DerefMut, Index, IndexMut};
+
+use indextree::{Arena, NodeId};
+
+use super::{AstNode, AstNodeId, SemanticNode};
+
+/// Untyped AST nodes flattened into an indextree
+#[derive(Debug, Default)]
+pub struct AstNodes<'a> {
+    /// The memory storage of the indextree is backed by a vector,
+    /// which allows for efficient traversal.
+    /// This also allows for parallel traversal by using `rayon`.
+    nodes: Arena<SemanticNode<'a>>,
+}
+
+impl<'a> Index<NodeId> for AstNodes<'a> {
+    type Output = AstNode<'a>;
+
+    fn index(&self, id: NodeId) -> &Self::Output {
+        &self.nodes[id]
+    }
+}
+
+impl<'a> IndexMut<NodeId> for AstNodes<'a> {
+    fn index_mut(&mut self, id: NodeId) -> &mut AstNode<'a> {
+        &mut self.nodes[id]
+    }
+}
+
+impl<'a> Index<AstNodeId> for AstNodes<'a> {
+    type Output = SemanticNode<'a>;
+
+    fn index(&self, id: AstNodeId) -> &Self::Output {
+        self.nodes[id.indextree_id()].get()
+    }
+}
+
+impl<'a> IndexMut<AstNodeId> for AstNodes<'a> {
+    fn index_mut(&mut self, id: AstNodeId) -> &mut SemanticNode<'a> {
+        self.nodes[id.indextree_id()].get_mut()
+    }
+}
+
+impl<'a> Deref for AstNodes<'a> {
+    type Target = Arena<SemanticNode<'a>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.nodes
+    }
+}
+
+impl<'a> DerefMut for AstNodes<'a> {
+    fn deref_mut(&mut self) -> &mut Arena<SemanticNode<'a>> {
+        &mut self.nodes
+    }
+}