diff --git a/proxy/tg_ws_proxy.py b/proxy/tg_ws_proxy.py
index f25738c..934ce17 100644
--- a/proxy/tg_ws_proxy.py
+++ b/proxy/tg_ws_proxy.py
@@ -618,6 +618,7 @@ async def _bridge_ws(reader, writer, ws: RawWebSocket, label,
     up_packets = 0
     down_packets = 0
     start_time = asyncio.get_event_loop().time()
+    last_recv_time = start_time
 
     async def tcp_to_ws():
         nonlocal up_bytes, up_packets
@@ -644,31 +645,48 @@ async def _bridge_ws(reader, writer, ws: RawWebSocket, label,
             log.debug("[%s] tcp->ws ended: %s", label, e)
 
     async def ws_to_tcp():
-        nonlocal down_bytes, down_packets
+        nonlocal down_bytes, down_packets, last_recv_time
         try:
             while True:
                 data = await ws.recv()
                 if data is None:
                     break
+                last_recv_time = asyncio.get_event_loop().time()
                 n = len(data)
                 _stats.bytes_down += n
                 down_bytes += n
                 down_packets += 1
                 writer.write(data)
-                # drain only when kernel buffer is filling up
-                buf = writer.transport.get_write_buffer_size()
-                if buf > _SEND_BUF:
-                    await writer.drain()
+                await writer.drain()
         except (asyncio.CancelledError, ConnectionError, OSError):
             return
         except Exception as e:
             log.debug("[%s] ws->tcp ended: %s", label, e)
 
+    async def ws_keepalive():
+        try:
+            while not ws._closed:
+                await asyncio.sleep(2)
+                idle = asyncio.get_event_loop().time() - last_recv_time
+                if idle >= 2 and not ws._closed:
+                    try:
+                        ws.writer.write(
+                            ws._build_frame(ws.OP_PING, b'', mask=True))
+                        await ws.writer.drain()
+                        log.debug("[%s] %s WS PING (idle %.1fs)",
+                                  label, dc_tag, idle)
+                    except Exception:
+                        break
+        except asyncio.CancelledError:
+            pass
+
+    ka_task = asyncio.create_task(ws_keepalive())
     tasks = [asyncio.create_task(tcp_to_ws()),
              asyncio.create_task(ws_to_tcp())]
     try:
         await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
     finally:
+        ka_task.cancel()
         for t in tasks:
             t.cancel()
         for t in tasks:
diff --git a/stress_test.py b/stress_test.py
new file mode 100644
index 0000000..f2fd88c
--- /dev/null
+++ b/stress_test.py
@@ -0,0 +1,246 @@
+"""
+Stress-test: сравнение OLD vs NEW реализаций горячих функций прокси.
+
+Тестируются:
+  1. _build_frame  — сборка WS-фрейма (masked binary)
+  2. _build_frame  — сборка WS-фрейма (unmasked)
+  3. _socks5_reply — генерация SOCKS5-ответа
+  4. _dc_from_init XOR-часть (bytes(a^b for …) vs int.from_bytes)
+  5. mask key generation (os.urandom vs PRNG)
+"""
+
+import gc
+import os
+import random
+import struct
+import time
+
+# ── Размеры данных, типичные для Telegram ──────────────────────────
+SMALL = 64          # init-пакет / ack
+MEDIUM = 1024       # текстовое сообщение
+LARGE = 65536       # фото / голосовое
+
+
+# ═══════════════════════════════════════════════════════════════════
+#  XOR mask (не менялся — для полноты)
+# ═══════════════════════════════════════════════════════════════════
+
+def xor_mask(data: bytes, mask: bytes) -> bytes:
+    if not data:
+        return data
+    n = len(data)
+    mask_rep = (mask * (n // 4 + 1))[:n]
+    return (int.from_bytes(data, 'big') ^ int.from_bytes(mask_rep, 'big')).to_bytes(n, 'big')
+
+
+# ═══════════════════════════════════════════════════════════════════
+#  _build_frame
+# ═══════════════════════════════════════════════════════════════════
+
+def build_frame_old(opcode: int, data: bytes, mask: bool = False) -> bytes:
+    """Старая: bytearray + append/extend + os.urandom."""
+    header = bytearray()
+    header.append(0x80 | opcode)
+    length = len(data)
+    mask_bit = 0x80 if mask else 0x00
+
+    if length < 126:
+        header.append(mask_bit | length)
+    elif length < 65536:
+        header.append(mask_bit | 126)
+        header.extend(struct.pack('>H', length))
+    else:
+        header.append(mask_bit | 127)
+        header.extend(struct.pack('>Q', length))
+
+    if mask:
+        mask_key = os.urandom(4)
+        header.extend(mask_key)
+        return bytes(header) + xor_mask(data, mask_key)
+    return bytes(header) + data
+
+
+# ── Новая: pre-compiled struct + PRNG ──────────────────────────────
+_st_BB = struct.Struct('>BB')
+_st_BBH = struct.Struct('>BBH')
+_st_BBQ = struct.Struct('>BBQ')
+_st_BB4s = struct.Struct('>BB4s')
+_st_BBH4s = struct.Struct('>BBH4s')
+_st_BBQ4s = struct.Struct('>BBQ4s')
+
+_mask_rng = random.Random(int.from_bytes(os.urandom(16), 'big'))
+_mask_pack = struct.Struct('>I').pack
+
+def _random_mask_key() -> bytes:
+    return _mask_pack(_mask_rng.getrandbits(32))
+
+def build_frame_new(opcode: int, data: bytes, mask: bool = False) -> bytes:
+    """Новая: struct.pack + PRNG mask."""
+    length = len(data)
+    fb = 0x80 | opcode
+
+    if not mask:
+        if length < 126:
+            return _st_BB.pack(fb, length) + data
+        if length < 65536:
+            return _st_BBH.pack(fb, 126, length) + data
+        return _st_BBQ.pack(fb, 127, length) + data
+
+    mask_key = _random_mask_key()
+    masked = xor_mask(data, mask_key)
+    if length < 126:
+        return _st_BB4s.pack(fb, 0x80 | length, mask_key) + masked
+    if length < 65536:
+        return _st_BBH4s.pack(fb, 0x80 | 126, length, mask_key) + masked
+    return _st_BBQ4s.pack(fb, 0x80 | 127, length, mask_key) + masked
+
+
+# ═══════════════════════════════════════════════════════════════════
+#  _socks5_reply
+# ═══════════════════════════════════════════════════════════════════
+
+def socks5_reply_old(status):
+    return bytes([0x05, status, 0x00, 0x01]) + b'\x00' * 6
+
+_SOCKS5_REPLIES = {s: bytes([0x05, s, 0x00, 0x01, 0, 0, 0, 0, 0, 0])
+                   for s in (0x00, 0x05, 0x07, 0x08)}
+
+def socks5_reply_new(status):
+    return _SOCKS5_REPLIES[status]
+
+
+# ═══════════════════════════════════════════════════════════════════
+#  dc_from_init XOR (8 байт keystream ^ data)
+# ═══════════════════════════════════════════════════════════════════
+
+def dc_xor_old(data8: bytes, ks8: bytes) -> bytes:
+    """Старая: генераторное выражение."""
+    return bytes(a ^ b for a, b in zip(data8, ks8))
+
+def dc_xor_new(data8: bytes, ks8: bytes) -> bytes:
+    """Новая: int.from_bytes."""
+    return (int.from_bytes(data8, 'big') ^ int.from_bytes(ks8, 'big')).to_bytes(8, 'big')
+
+
+# ═══════════════════════════════════════════════════════════════════
+#  mask key: os.urandom(4) vs PRNG
+# ═══════════════════════════════════════════════════════════════════
+
+def mask_key_old() -> bytes:
+    return os.urandom(4)
+
+def mask_key_new() -> bytes:
+    return _random_mask_key()
+
+
+# ═══════════════════════════════════════════════════════════════════
+#  Бенчмарк
+# ═══════════════════════════════════════════════════════════════════
+
+def bench(func, args_list: list, iters: int) -> float:
+    gc.collect()
+    for i in range(min(100, iters)):
+        func(*args_list[i % len(args_list)])
+    start = time.perf_counter()
+    for i in range(iters):
+        func(*args_list[i % len(args_list)])
+    elapsed = time.perf_counter() - start
+    return elapsed / iters * 1_000_000  # мкс
+
+
+def compare(name: str, old_fn, new_fn, args_list: list, iters: int):
+    t_old = bench(old_fn, args_list, iters)
+    t_new = bench(new_fn, args_list, iters)
+    speedup = t_old / t_new if t_new > 0 else float('inf')
+    marker = '✅' if speedup >= 1.0 else '⚠️'
+    print(f"  {name:.<42s} OLD {t_old:8.3f} мкс | NEW {t_new:8.3f} мкс | {speedup:5.2f}x {marker}")
+
+
+# ═══════════════════════════════════════════════════════════════════
+
+def main():
+    print("=" * 74)
+    print("  Stress Test: OLD vs NEW (горячие функции tg_ws_proxy)")
+    print("=" * 74)
+
+    N = 500_000
+
+    # # ── 1. _build_frame masked ────────────────────────────────────
+    # print(f"\n── _build_frame masked ({N:,} итераций) ──")
+    # for size, label in [(SMALL, "64B"), (MEDIUM, "1KB"), (LARGE, "64KB")]:
+    #     data_list = [(0x2, os.urandom(size), True) for _ in range(1000)]
+    #     compare(f"build_frame masked {label}",
+    #             build_frame_old, build_frame_new, data_list, N)
+
+    # # ── 2. _build_frame unmasked ──────────────────────────────────
+    # print(f"\n── _build_frame unmasked ({N:,} итераций) ──")
+    # for size, label in [(SMALL, "64B"), (MEDIUM, "1KB"), (LARGE, "64KB")]:
+    #     data_list = [(0x2, os.urandom(size), False) for _ in range(1000)]
+    #     compare(f"build_frame unmasked {label}",
+    #             build_frame_old, build_frame_new, data_list, N)
+
+    # # ── 3. mask key generation ────────────────────────────────────
+    # print(f"\n── mask key: os.urandom(4) vs PRNG ({N:,} итераций) ──")
+    # compare("mask_key", mask_key_old, mask_key_new, [()] * 100, N)
+
+    # # ── 4. _socks5_reply ─────────────────────────────────────────
+    N2 = 2_000_000
+    # print(f"\n── _socks5_reply ({N2:,} итераций) ──")
+    # compare("socks5_reply", socks5_reply_old, socks5_reply_new,
+    #         [(s,) for s in (0x00, 0x05, 0x07, 0x08)], N2)
+
+    # # ── 5. dc_from_init XOR (8 bytes) ────────────────────────────
+    # print(f"\n── dc_xor 8B: generator vs int.from_bytes ({N2:,} итераций) ──")
+    # compare("dc_xor_8B", dc_xor_old, dc_xor_new,
+    #         [(os.urandom(8), os.urandom(8)) for _ in range(1000)], N2)
+
+    # ── 6. _read_frame struct.unpack vs pre-compiled ─────────────
+    print(f"\n── struct unpack read-path ({N2:,} итераций) ──")
+    _st_H_pre = struct.Struct('>H')
+    _st_Q_pre = struct.Struct('>Q')
+    h_bufs = [(os.urandom(2),) for _ in range(1000)]
+    q_bufs = [(os.urandom(8),) for _ in range(1000)]
+    compare("unpack >H",
+            lambda b: struct.unpack('>H', b),
+            lambda b: _st_H_pre.unpack(b),
+            h_bufs, N2)
+    compare("unpack >Q",
+            lambda b: struct.unpack('>Q', b),
+            lambda b: _st_Q_pre.unpack(b),
+            q_bufs, N2)
+
+    # ── 7. dc_from_init: 2x unpack vs 1x merged ─────────────────
+    print(f"\n── dc_from_init unpack: 2 calls vs 1 merged ({N2:,} итераций) ──")
+    _st_Ih = struct.Struct('<Ih')
+    plains = [(os.urandom(8),) for _ in range(1000)]
+    def dc_unpack_old(p):
+        return struct.unpack('<I', p[0:4])[0], struct.unpack('<h', p[4:6])[0]
+    def dc_unpack_new(p):
+        return _st_Ih.unpack(p[:6])
+    compare("dc_unpack", dc_unpack_old, dc_unpack_new, plains, N2)
+
+    # ── 8. bytes() copy vs direct slice ──────────────────────────
+    print(f"\n── bytes(slice) vs direct slice ({N2:,} итераций) ──")
+    raw_data = [(os.urandom(64),) for _ in range(1000)]
+    def slice_copy(d):
+        return bytes(d[8:40]), bytes(d[40:56])
+    def slice_direct(d):
+        return d[8:40], d[40:56]
+    compare("bytes(slice) vs slice", slice_copy, slice_direct, raw_data, N2)
+
+    # ── 9. MsgSplitter unpack_from: struct vs pre-compiled ───────
+    print(f"\n── unpack_from <I: struct vs pre-compiled ({N2:,} итераций) ──")
+    _st_I_le = struct.Struct('<I')
+    splitter_bufs = [(os.urandom(64), 1) for _ in range(1000)]
+    compare("unpack_from <I",
+            lambda b, p: struct.unpack_from('<I', b, p),
+            lambda b, p: _st_I_le.unpack_from(b, p),
+            splitter_bufs, N2)
+
+    print("\n" + "=" * 74)
+    print("  Готово!")
+    print("=" * 74)
+
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file