diff --git a/main.py b/main.py
index f9a12b7..2d9e8dd 100644
--- a/main.py
+++ b/main.py
@@ -1,36 +1,38 @@
+import os
 import time
+import json
 import requests
 from datetime import datetime
+from pathlib import Path
 
 # ===== SMS GATEWAY =====
-SMS_USER = "weatherbot"
-SMS_PASS = "Cupakabra17"
+SMS_USER = os.getenv("SMS_USER", "weatherbot")
+SMS_PASS = os.getenv("SMS_PASS", "Cupakabra17")
 
 RECEIVE_URL = "https://sms.internet-master.cz/receive/"
 SEND_URL    = "https://sms.internet-master.cz/send/"
 
-POLL_INTERVAL = 1   # 🔥 1 second polling (worst-case ≤5s)
-MAX_ERRORS_BEFORE_SLEEP = 3
+# Latency target: worst-case <= ~5s
+POLL_INTERVAL = 1  # seconds
 
-seen_offsets = set()
-error_count = 0
+# Persistence
+STATE_FILE = Path("weatherbot_state.json")
+MAX_SEEN_OFFSETS = 5000  # cap memory/state growth
 
 HEADERS = {
     "User-Agent": "weatherbot/1.0 (jakub@jimbuntu)"
 }
 
-# =======================
-
 session = requests.Session()
 session.headers.update(HEADERS)
 
-def fetch_inbox():
+def fetch_inbox(limit=5):
     r = session.get(
         RECEIVE_URL,
         params={
             "username": SMS_USER,
             "password": SMS_PASS,
-            "limit": 5
+            "limit": limit
         },
         timeout=5
     )
@@ -64,7 +66,6 @@ def get_weather(city):
         return f"❌ Weather unavailable for {city}"
 
     msg = f"🌦 Weather for {city}:\n"
-
     for day in weather[:3]:
         date = day["date"]
         avgtemp = day["avgtempC"]
@@ -74,40 +75,120 @@ def get_weather(city):
 
     return msg.strip()
 
-# ===== MAIN LOOP =====
-print("📡 SMS Weather Bot started (≤5s reply mode)")
+def load_state():
+    if not STATE_FILE.exists():
+        return {"seen_offsets": []}
+    try:
+        with STATE_FILE.open("r", encoding="utf-8") as f:
+            data = json.load(f)
+        if not isinstance(data, dict):
+            return {"seen_offsets": []}
+        if "seen_offsets" not in data or not isinstance(data["seen_offsets"], list):
+            data["seen_offsets"] = []
+        return data
+    except Exception:
+        # If state is corrupt, start clean (but startup priming still prevents backlog replies)
+        return {"seen_offsets": []}
+
+def save_state(state):
+    # Keep only the newest N offsets (as ints if possible)
+    seen = state.get("seen_offsets", [])
+    if len(seen) > MAX_SEEN_OFFSETS:
+        seen = seen[-MAX_SEEN_OFFSETS:]
+        state["seen_offsets"] = seen
+
+    tmp = STATE_FILE.with_suffix(".json.tmp")
+    with tmp.open("w", encoding="utf-8") as f:
+        json.dump(state, f, ensure_ascii=False)
+    tmp.replace(STATE_FILE)
+
+def prime_seen_offsets(seen_set):
+    """
+    On startup, mark whatever is currently in the inbox as 'already seen'
+    so we do NOT reply to backlog after a restart.
+    """
+    try:
+        data = fetch_inbox(limit=20)
+        inbox = data.get("inbox", [])
+        primed = 0
+        for sms in inbox:
+            offset = sms.get("offset")
+            if offset is None:
+                continue
+            if offset not in seen_set:
+                seen_set.add(offset)
+                primed += 1
+        if primed:
+            print(f"🧹 Primed {primed} existing message(s) as already-seen (no backlog replies).")
+        else:
+            print("🧹 No existing messages to prime.")
+    except Exception as e:
+        print("⚠ Prime failed (continuing):", e)
+
+def add_seen(seen_set, seen_list, offset):
+    # offset can be int/str depending on API; store exactly as returned
+    if offset in seen_set:
+        return False
+    seen_set.add(offset)
+    seen_list.append(offset)
+    # cap list size
+    if len(seen_list) > MAX_SEEN_OFFSETS:
+        # drop oldest chunk
+        drop = len(seen_list) - MAX_SEEN_OFFSETS
+        for old in seen_list[:drop]:
+            seen_set.discard(old)
+        del seen_list[:drop]
+    return True
+
+# ===== MAIN =====
+print("📡 SMS Weather Bot started (≤5s reply + persistent offsets)")
+
+state = load_state()
+seen_list = state.get("seen_offsets", [])
+seen_set = set(seen_list)
+
+# Prevent replying to old messages sitting in inbox after restart
+prime_seen_offsets(seen_set)
+# Sync list to set after priming (preserve order by appending primed ones)
+# (We don't know which were primed vs existing; easiest is to rewrite list from set as a stable list)
+# But to preserve bounded size, we just extend list with items missing:
+for off in list(seen_set):
+    if off not in seen_list:
+        seen_list.append(off)
+state["seen_offsets"] = seen_list
+save_state(state)
 
 while True:
     try:
-        data = fetch_inbox()
+        data = fetch_inbox(limit=5)
         inbox = data.get("inbox", [])
 
-        error_count = 0  # reset on success
-
         for sms in inbox:
-            offset = sms["offset"]
-            if offset in seen_offsets:
+            offset = sms.get("offset")
+            if offset is None:
                 continue
 
-            phone = sms["phone"]
-            text  = sms["message"].strip()
+            # If already processed, skip
+            if offset in seen_set:
+                continue
+
+            phone = sms.get("phone", "")
+            text = (sms.get("message") or "").strip()
+
+            # Mark seen immediately to avoid duplicate replies if send fails mid-loop
+            add_seen(seen_set, seen_list, offset)
+            state["seen_offsets"] = seen_list
+            save_state(state)
 
             print(f"📨 {phone}: {text}")
 
             reply = get_weather(text)
             send_sms(phone, reply)
 
-            seen_offsets.add(offset)
             print(f"✅ Replied to {phone}")
 
     except Exception as e:
-        error_count += 1
         print("⚠ ERROR:", e)
+        # Keep latency target: no long backoff; next poll in 1s
 
-        # If gateway is unstable, slow down briefly
-        if error_count >= MAX_ERRORS_BEFORE_SLEEP:
-            print("⏳ Too many errors, sleeping 5s")
-            time.sleep(5)
-            error_count = 0
-
-    time.sleep(POLL_INTERVAL)
\ No newline at end of file
+    time.sleep(POLL_INTERVAL)