diff --git a/README.md b/README.md
index 9c52c5c..8c7bf82 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,15 @@ It progresses **only during your scheduled work hours**
 - During the day, the bar fills smoothly
 - End of Wednesday = **100% freedom**
 
+### Configuration
+
+| Variable | Default | Description |
+|--------|---------|-------------|
+| WORK_START_TIME | 07:00 | Workday start (HH:MM) |
+| WORK_END_TIME | 17:30 | Workday end (HH:MM) |
+| WORK_DAYS | 0,1,2,3 | JS day numbers (Sun=0) |
+| UPDATE_INTERVAL_MS | 60000 | Update frequency |
+
 ---
 
 ## 🛠 Tech Stack
diff --git a/app.py b/app.py
index 7fcc529..b2b34d5 100644
--- a/app.py
+++ b/app.py
@@ -1,10 +1,41 @@
+import os
 from flask import Flask, render_template
 
 app = Flask(__name__)
 
+def parse_time(value, default):
+    try:
+        hour, minute = map(int, value.split(":"))
+        return {"hour": hour, "minute": minute}
+    except Exception:
+        return default
+
 @app.route("/")
 def index():
-    return render_template("index.html")
+    start_time = parse_time(
+        os.getenv("WORK_START_TIME", "07:00"),
+        {"hour": 7, "minute": 0}
+    )
+    end_time = parse_time(
+        os.getenv("WORK_END_TIME", "17:30"),
+        {"hour": 17, "minute": 30}
+    )
+
+    work_days = [
+        int(d.strip())
+        for d in os.getenv("WORK_DAYS", "0,1,2,3").split(",")
+        if d.strip().isdigit()
+    ]
+
+    update_interval = int(os.getenv("UPDATE_INTERVAL_MS", "60000"))
+
+    return render_template(
+        "index.html",
+        work_start=start_time,
+        work_end=end_time,
+        work_days=work_days,
+        update_interval=update_interval
+    )
 
 if __name__ == "__main__":
-    app.run(host="0.0.0.0", port=5000, debug=True)
+    app.run(host="0.0.0.0", port=5000)
diff --git a/templates/index.html b/templates/index.html
index 072fef7..73c51fc 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -25,14 +25,34 @@
     <div class="percent weekly-percent" id="weeklyPercent">0%</div>
   </div>
 
-  <script>
-    const WORK_START_HOUR = 7;
-    const WORK_START_MINUTE = 0;
-    const WORK_END_HOUR = 17;
-    const WORK_END_MINUTE = 30;
+  <!-- App configuration -->
+  <script id="app-config" type="application/json">
+    {{ {
+      "workStart": work_start,
+      "workEnd": work_end,
+      "workDays": work_days,
+      "updateInterval": update_interval
+    } | tojson }}
+  </script>
+
+  <!-- Application logic -->
+  <script>
+    const config = JSON.parse(
+      document.getElementById("app-config").textContent
+    );
+
+    const WORK_START_HOUR = config.workStart.hour;
+    const WORK_START_MINUTE = config.workStart.minute;
+    const WORK_END_HOUR = config.workEnd.hour;
+    const WORK_END_MINUTE = config.workEnd.minute;
+
+    const WORK_DAYS = config.workDays;
+    const UPDATE_INTERVAL = config.updateInterval;
+
+    const TOTAL_WORK_MINUTES =
+      (WORK_END_HOUR * 60 + WORK_END_MINUTE) -
+      (WORK_START_HOUR * 60 + WORK_START_MINUTE);
 
-    const TOTAL_WORK_MINUTES = 630; // 10.5 hours
-    const WORK_DAYS = [0, 1, 2, 3]; // Sunday → Wednesday
     const WEEKLY_DAY_WEIGHT = 100 / WORK_DAYS.length;
 
     function updateProgress() {
@@ -64,16 +84,19 @@
         statusText.textContent = "Workday complete 🎉";
       } else {
         const elapsedMinutes = Math.floor((now - start) / 60000);
-        dailyPercent = Math.min((elapsedMinutes / TOTAL_WORK_MINUTES) * 100, 100);
+        dailyPercent = Math.min(
+          (elapsedMinutes / TOTAL_WORK_MINUTES) * 100,
+          100
+        );
         statusText.textContent = "Grinding…";
       }
 
-      // Apply daily progress
+      // Daily progress
       dailyFill.style.width = dailyPercent + "%";
       dailyPercentText.textContent = dailyPercent.toFixed(1) + "%";
 
       // Weekly progress
-      let completedDays = WORK_DAYS.filter(d => d < day).length;
+      const completedDays = WORK_DAYS.filter(d => d < day).length;
       let weeklyPercent =
         (completedDays * WEEKLY_DAY_WEIGHT) +
         (isWorkday ? (dailyPercent / 100) * WEEKLY_DAY_WEIGHT : 0);
@@ -85,7 +108,7 @@
     }
 
     updateProgress();
-    setInterval(updateProgress, 30 * 1000);
+    setInterval(updateProgress, UPDATE_INTERVAL);
   </script>
 </body>
 </html>