diff --git a/lib/shopify_api/auth/associated_user.rb b/lib/shopify_api/auth/associated_user.rb
index 7f7cd6e70..df8835e27 100644
--- a/lib/shopify_api/auth/associated_user.rb
+++ b/lib/shopify_api/auth/associated_user.rb
@@ -31,6 +31,25 @@ def ==(other)
           false
         end
       end
+
+      sig { returns(Hash) }
+      def to_h
+        {
+          id: id,
+          first_name: first_name,
+          last_name: last_name,
+          email: email,
+          email_verified: email_verified,
+          account_owner: account_owner,
+          locale: locale,
+          collaborator: collaborator
+        }
+      end
+
+      sig { returns(String) }
+      def to_json
+        to_h.to_json
+      end
     end
   end
 end
diff --git a/lib/shopify_api/auth/session.rb b/lib/shopify_api/auth/session.rb
index 1fba413b0..16fe9172a 100644
--- a/lib/shopify_api/auth/session.rb
+++ b/lib/shopify_api/auth/session.rb
@@ -117,7 +117,7 @@ def from(shop:, access_token_response:)
 
         sig { params(str: String).returns(Session) }
         def deserialize(str)
-          Oj.load(str)
+          JSON.load(str)
         end
       end
 
@@ -134,7 +134,7 @@ def copy_attributes_from(other)
 
       sig { returns(String) }
       def serialize
-        Oj.dump(self)
+        JSON.dump(self)
       end
 
       alias_method :eql?, :==
@@ -156,6 +156,27 @@ def ==(other)
           false
         end
       end
+
+      sig { returns(T::Hash[Symbol, T.untyped]) }
+      def to_h
+        {
+          id: id,
+          shop: shop,
+          state: state,
+          access_token: access_token,
+          scope: scope.to_a,
+          associated_user_scope: associated_user_scope&.to_a,
+          expires: expires&.to_i,
+          is_online: online?,
+          associated_user: associated_user&.to_h,
+          shopify_session_id: shopify_session_id,
+        }
+      end
+
+      sig { returns(String) }
+      def to_json
+        to_h.to_json
+      end
     end
   end
 end