I Built a Free Online Alarm Clock That Runs in Your Browser — Here's How

The Problem

Every time I needed a quick timer while working at my laptop,
I grabbed my phone. Then saw notifications. Then lost 20 minutes.

There had to be a better way.

The Solution

I built AlarmOnline24 — a completely browser-based alarm
clock. No app, no download, no sign-up.

👉 alarmonline24.com

Features

• Quick presets: 5, 10, 15, 30, 45 min, 1hr, 2hr
• Multiple alarm sounds + volume control
• Real-time countdown & progress tracker
• Dark mode
• Works on PC, Mac, iPhone, Android
• 100% free — forever

Tech Stack

• Vanilla JavaScript (Web Audio API for sound)
• Pure CSS (fully responsive)
• No frameworks, no dependencies
• Runs entirely client-side

Why No Framework?

Speed. A timer should load in milliseconds.
No React, no Vue — just fast, clean code.

Would love feedback from the DEV community! 🙏