diff --git a/scanner.go b/scanner.go
index 96cdaf0..c559ba1 100644
--- a/scanner.go
+++ b/scanner.go
@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"io"
 	"strconv"
-	"strings"
 	"unicode"
 )
 
@@ -393,9 +392,11 @@ func (s *Scanner) ScanString() (any, error) {
 		return nil, err
 	}
 
-	var builder strings.Builder
-	builder.Grow(64) // Preallocate with reasonable capacity
+	// Reset buffer while preserving capacity
+	s.buffer = s.buffer[:0]
 
+	// Avoid strings.Builder as it creates a new array internally
+	// and instead use our rune buffer directly
 	for {
 		r, _, err := s.ReadRune()
 		if err != nil {
@@ -414,23 +415,23 @@ func (s *Scanner) ScanString() (any, error) {
 			}
 			switch escaped {
 			case '"':
-				builder.WriteRune('"')
+				s.buffer = append(s.buffer, '"')
 			case '\\':
-				builder.WriteRune('\\')
+				s.buffer = append(s.buffer, '\\')
 			case 'n':
-				builder.WriteRune('\n')
+				s.buffer = append(s.buffer, '\n')
 			case 't':
-				builder.WriteRune('\t')
+				s.buffer = append(s.buffer, '\t')
 			default:
-				builder.WriteRune('\\')
-				builder.WriteRune(escaped)
+				s.buffer = append(s.buffer, '\\', escaped)
 			}
 		} else {
-			builder.WriteRune(r)
+			s.buffer = append(s.buffer, r)
 		}
 	}
 
-	return builder.String(), nil
+	// Convert rune slice to string once at the end
+	return string(s.buffer), nil
 }
 
 // ConvertValue converts string values to their appropriate types