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Md Mijanur Molla
Md Mijanur Molla

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# I Created a “Last Seen” Challenge… And Users Stayed Online Forever 👀

You’ve seen this before.

Someone is “Online”…

You send a message…

No reply.

Still “Online”…

Minutes pass… nothing.

👉 Something feels off.

This is a real-world bug.

So I created a challenge on VibeCode Arena to test how systems handle online status.

And the results were interesting.


🚨 The Problem

At first glance, the logic looks simple:

  • User opens app → set Online
  • User leaves → set Offline
  • Show last seen time

Everything seems correct.

But real-world systems are not that predictable.


⚠️ What Can Go Wrong?

In real applications:

• User closes app suddenly (no logout event)

• Network disconnect happens silently

• “Offline” event is never sent

• System still thinks user is online

And suddenly:

👉 User appears online forever

👉 Last seen becomes incorrect

👉 System shows misleading information


🧠 What I Observed

When AI models tried this challenge:

  • Some handled basic online/offline logic
  • Many ignored sudden disconnects
  • Some didn’t handle timeouts
  • Very few handled real-time reliability

The code works.

But the system lies.


🔍 The Real Issue

This is not just about status.

It’s about presence tracking.

Because:

👉 Events can be missed

👉 Connections can drop

👉 State can become stale

And systems must recover from that.


💡 What a Better System Needs

A proper presence system should:

  • Use heartbeat (ping every few seconds)
  • Add timeout for inactivity
  • Handle sudden disconnects
  • Use WebSockets for real-time updates
  • Continuously refresh user state

This ensures:

👉 Accurate online status

👉 Correct last seen

👉 Reliable user experience


🔥 Try My Challenge

I created this challenge to test real-time system thinking.

👉 Try it here:
https://vibecodearena.ai/duel/54ea165c-eb09-438b-941e-7315e8e224ac

Can you:

  • Fix incorrect online status?
  • Handle disconnects properly?
  • Build a reliable presence system?

🎯 Final Thought

Online status is not about showing activity.

It’s about showing accurate activity.

Because even a small delay…

👉 Can make the system look wrong.


Try it and tell me 👇

Did AI handle presence correctly… or keep users online forever?

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