diff --git a/decode.v b/decode.v
index d7223d1..22e6275 100644
--- a/decode.v
+++ b/decode.v
@@ -31,7 +31,11 @@ pub fn (mut d Decoder) decode_to_json[T](src []u8) !string {
 	d.buffer = src
 	d.next()!
 
-	mut result := ''
+	mut result := []u8{}
+
+	defer {
+		unsafe { result.free() }
+	}
 
 	data := d.buffer
 
@@ -41,72 +45,75 @@ pub fn (mut d Decoder) decode_to_json[T](src []u8) !string {
 
 			mut d_for_array := new_decoder()
 
-			result += '['
+			result << `[`
 
 			for i in 0 .. array_len {
 				if i > 0 {
-					result += ','
+					result << `,`
 				}
 
 				element_json := d_for_array.decode_to_json[T](data[1..]) or {
 					return error('error converting array element to JSON ${err}')
 				}
 
-				result += element_json
+				unsafe { result.push_many(element_json.str, element_json.len) }
 			}
 
-			result += ']'
+			result << `]`
 		}
 		mp_map_16, mp_map_32, mp_fix_map_min...mp_fix_map_max {
 			map_len := d.read_map_len(src) or { return error('error reading map length') }
 
-			result += '{'
+			result << `{`
 
 			for i in 0 .. map_len {
 				if i > 0 {
-					result += ','
+					result << `,`
 				}
 
 				key := d.decode_to_json[string](src) or {
 					return error('error converting map key to JSON: ${err}')
 				}
+				unsafe { result.push_many(key.str, key.len) }
+				result << `:`
 
 				value_json := d.decode_to_json[T](src) or {
 					return error('error converting map value to JSON')
 				}
-
-				result += '${key}:${value_json}'
+				unsafe { result.push_many(value_json.str().str, value_json.str().len) }
 			}
 
-			result += '}'
+			result << `}`
 		}
 		mp_nil {
-			result += 'null'
+			unsafe { result.push_many('null'.str, 'null'.len) }
 		}
 		mp_true, mp_false {
 			mut bool_val := false
 			d.decode_bool(mut bool_val) or { return error('error decoding boolean: ${err}') }
-			result += bool_val.str()
+			unsafe { result.push_many(bool_val.str().str, bool_val.str().len) }
 		}
 		mp_f32, mp_f64 {
 			mut float_val := 0.0
 			d.decode_float(mut float_val) or { return error('error decoding float: ${err}') }
-			result += float_val.str()
+			unsafe { result.push_many(float_val.str().str, float_val.str().len) }
 		}
 		mp_u8, mp_u16, mp_u32, mp_u64, mp_i8, mp_i16, mp_i32, mp_i64 {
 			mut int_val := 0
 			d.decode_integer(mut int_val) or { return error('error decoding integer: ${err}') }
-			result += int_val.str()
+			unsafe { result.push_many(int_val.str().str, int_val.str().len) }
 		}
 		mp_str_8, mp_str_16, mp_str_32, mp_fix_str_min...mp_fix_str_max {
 			mut str_val := ''
 			d.decode_string(mut str_val) or { return error('error decoding string: ${err}') }
-			result += '"${str_val}"'
+			result << `\"`
+			unsafe { result.push_many(str_val.str, str_val.len) }
+			result << `\"`
 		}
 		mp_bin_8, mp_bin_16, mp_bin_32 {
 			bin_len := d.read_bin_len(src) or { return error('error reading binary length') }
 			for i in 0 .. bin_len {
-				result += src[d.pos + i].str()
+				unsafe { result.push_many(src[d.pos + i].str().str, src[d.pos + i].str().len) }
 			}
 
 			d.pos += bin_len
@@ -117,7 +124,7 @@ pub fn (mut d Decoder) decode_to_json[T](src []u8) !string {
 			return error('unsupported descriptor byte for conversion to JSON')
 		}
 	}
-	return result
+	return result.bytestr()
 }
 
 pub fn decode[T](src []u8) !T {
diff --git a/encode.v b/encode.v
index 9264fa3..628c540 100644
--- a/encode.v
+++ b/encode.v
@@ -1,12 +1,11 @@
 module msgpack
 
-import strings
 import math
 import time
 
 struct Encoder {
 mut:
-	buffer strings.Builder = strings.new_builder(1024)
+	buffer []u8
 	config Config = default_config()
 }
 
@@ -114,9 +113,9 @@ pub fn (mut e Encoder) encode[T](data T) []u8 {
 
 pub fn (mut e Encoder) encode_bool(b bool) {
 	if b {
-		e.buffer.write_u8(mp_true)
+		e.buffer << mp_true
 	} else {
-		e.buffer.write_u8(mp_false)
+		e.buffer << mp_false
 	}
 }
 
@@ -354,7 +353,9 @@ pub fn (mut e Encoder) write_map_start(length int) {
 }
 
 fn (mut e Encoder) write_string(s string) {
-	e.buffer.write_string(s)
+	if s.len > 0 {
+		unsafe { e.buffer.push_many(s.str, s.len) }
+	}
 }
 
 fn (mut e Encoder) write_u16(i u16) {
@@ -379,14 +380,14 @@ pub fn (mut e Encoder) write_f64(f f64) {
 
 // write byte array
 fn (mut e Encoder) write(b []u8) {
-	e.buffer.write(b) or { panic('write error') }
+	unsafe { e.buffer.push_many(b.bytestr().str, b.bytestr().len) }
 }
 
 // write one or more bytes
 fn (mut e Encoder) write_u8(b ...u8) {
 	if b.len > 1 {
-		e.write(b)
+		e.buffer << b
 	} else {
-		e.buffer.write_u8(b[0])
+		e.buffer << b[0]
 	}
 }
diff --git a/examples/bench_msgpack_json_vs_json2.v b/examples/bench_msgpack_json_vs_json2.v
index de83d6e..ad603c6 100644
--- a/examples/bench_msgpack_json_vs_json2.v
+++ b/examples/bench_msgpack_json_vs_json2.v
@@ -4,18 +4,19 @@ import os
 import json
 import x.json2
 import msgpack
-import time
 import benchmark
+// import time
 
 struct Person {
-	name       string
-	age        int
-	created_at time.Time
+	name string
+	age  int
+	// created_at time.Time
 }
 
 fn main() {
-	max_iterations := os.getenv_opt('MAX_ITERATIONS') or { '1000' }.int()
-	s := '{"name":"Bilbo Baggins","age":99,"created_at":1670840340}'
+	max_iterations := os.getenv_opt('MAX_ITERATIONS') or { '1000000' }.int()
+	// s := '{"name":"Bilbo Baggins","age":99,"created_at":1670840340}'
+	s := '{"name":"Bilbo Baggins","age":99}'
 	mut b := benchmark.start()
 
 	for _ in 0 .. max_iterations {