diff --git a/crates/builder/src/graph/adj_list.rs b/crates/builder/src/graph/adj_list.rs
index 71f793d..5e77c58 100644
--- a/crates/builder/src/graph/adj_list.rs
+++ b/crates/builder/src/graph/adj_list.rs
@@ -58,8 +58,28 @@ impl<NI: Idx, EV> AdjacencyList<NI, EV> {
     #[inline]
     pub(crate) fn insert(&self, source: NI, target: Target<NI, EV>) {
         let mut edges = self.edges[source.index()].write().unwrap();
+        Self::apply_layout(self.layout, &mut edges, target);
+    }
 
-        match self.layout {
+    #[inline]
+    pub(crate) fn insert_mut(&mut self, source: NI, target: Target<NI, EV>) {
+        let edges = self.edges[source.index()].get_mut().unwrap();
+        Self::apply_layout(self.layout, edges, target);
+    }
+
+    #[inline]
+    fn check_bounds(&self, node: NI) -> Result<(), crate::Error> {
+        if node >= self.node_count() {
+            return Err(crate::Error::MissingNode {
+                node: format!("{}", node.index()),
+            });
+        };
+        Ok(())
+    }
+
+    #[inline]
+    fn apply_layout(layout: CsrLayout, edges: &mut Vec<Target<NI, EV>>, target: Target<NI, EV>) {
+        match layout {
             CsrLayout::Sorted => match edges.binary_search(&target) {
                 Ok(i) => edges.insert(i, target),
                 Err(i) => edges.insert(i, target),
@@ -345,26 +365,35 @@ impl<NI: Idx, NV> EdgeMutation<NI> for DirectedALGraph<NI, NV> {
     fn add_edge(&self, source: NI, target: NI) -> Result<(), crate::Error> {
         self.add_edge_with_value(source, target, ())
     }
+
+    fn add_edge_mut(&mut self, source: NI, target: NI) -> Result<(), crate::Error> {
+        self.add_edge_with_value_mut(source, target, ())
+    }
 }
 
 impl<NI: Idx, NV, EV: Copy> EdgeMutationWithValues<NI, EV> for DirectedALGraph<NI, NV, EV> {
     fn add_edge_with_value(&self, source: NI, target: NI, value: EV) -> Result<(), crate::Error> {
-        if source >= self.al_out.node_count() {
-            return Err(crate::Error::MissingNode {
-                node: format!("{}", source.index()),
-            });
-        }
-        if target >= self.al_inc.node_count() {
-            return Err(crate::Error::MissingNode {
-                node: format!("{}", target.index()),
-            });
-        }
-
+        self.al_out.check_bounds(source)?;
+        self.al_inc.check_bounds(target)?;
         self.al_out.insert(source, Target::new(target, value));
         self.al_inc.insert(target, Target::new(source, value));
 
         Ok(())
     }
+
+    fn add_edge_with_value_mut(
+        &mut self,
+        source: NI,
+        target: NI,
+        value: EV,
+    ) -> Result<(), crate::Error> {
+        self.al_out.check_bounds(source)?;
+        self.al_inc.check_bounds(target)?;
+        self.al_out.insert_mut(source, Target::new(target, value));
+        self.al_inc.insert_mut(target, Target::new(source, value));
+
+        Ok(())
+    }
 }
 
 impl<NI, EV, E> From<(E, CsrLayout)> for DirectedALGraph<NI, (), EV>
@@ -482,26 +511,35 @@ impl<NI: Idx, NV> EdgeMutation<NI> for UndirectedALGraph<NI, NV, ()> {
     fn add_edge(&self, source: NI, target: NI) -> Result<(), crate::Error> {
         self.add_edge_with_value(source, target, ())
     }
+
+    fn add_edge_mut(&mut self, source: NI, target: NI) -> Result<(), crate::Error> {
+        self.add_edge_with_value_mut(source, target, ())
+    }
 }
 
 impl<NI: Idx, NV, EV: Copy> EdgeMutationWithValues<NI, EV> for UndirectedALGraph<NI, NV, EV> {
     fn add_edge_with_value(&self, source: NI, target: NI, value: EV) -> Result<(), crate::Error> {
-        if source >= self.al.node_count() {
-            return Err(crate::Error::MissingNode {
-                node: format!("{}", source.index()),
-            });
-        }
-        if target >= self.al.node_count() {
-            return Err(crate::Error::MissingNode {
-                node: format!("{}", target.index()),
-            });
-        }
-
+        self.al.check_bounds(source)?;
+        self.al.check_bounds(target)?;
         self.al.insert(source, Target::new(target, value));
         self.al.insert(target, Target::new(source, value));
 
         Ok(())
     }
+
+    fn add_edge_with_value_mut(
+        &mut self,
+        source: NI,
+        target: NI,
+        value: EV,
+    ) -> Result<(), crate::Error> {
+        self.al.check_bounds(source)?;
+        self.al.check_bounds(target)?;
+        self.al.insert_mut(source, Target::new(target, value));
+        self.al.insert_mut(target, Target::new(source, value));
+
+        Ok(())
+    }
 }
 
 impl<NI, EV, E> From<(E, CsrLayout)> for UndirectedALGraph<NI, (), EV>
diff --git a/crates/builder/src/lib.rs b/crates/builder/src/lib.rs
index 9192131..cd4c93a 100644
--- a/crates/builder/src/lib.rs
+++ b/crates/builder/src/lib.rs
@@ -420,6 +420,16 @@ pub trait EdgeMutation<NI: Idx> {
     /// If either the source or the target node does not exist,
     /// the method will return [`Error::MissingNode`].
     fn add_edge(&self, source: NI, target: NI) -> Result<(), Error>;
+
+    /// Adds a new edge between the given source and target node.
+    ///
+    /// Does not require locking the node-local list due to `&mut self`.
+    ///
+    /// # Errors
+    ///
+    /// If either the source or the target node does not exist,
+    /// the method will return [`Error::MissingNode`].
+    fn add_edge_mut(&mut self, source: NI, target: NI) -> Result<(), Error>;
 }
 
 /// Allows adding new edges to a graph.
@@ -432,6 +442,17 @@ pub trait EdgeMutationWithValues<NI: Idx, EV> {
     /// If either the source or the target node does not exist,
     /// the method will return [`Error::MissingNode`].
     fn add_edge_with_value(&self, source: NI, target: NI, value: EV) -> Result<(), Error>;
+
+    /// Adds a new edge between the given source and target node
+    /// and assigns the given value to it.
+    ///
+    /// Does not require locking the node-local list due to `&mut self`.
+    ///
+    /// # Errors
+    ///
+    /// If either the source or the target node does not exist,
+    /// the method will return [`Error::MissingNode`].
+    fn add_edge_with_value_mut(&mut self, source: NI, target: NI, value: EV) -> Result<(), Error>;
 }
 
 #[repr(transparent)]