I built a LAN messenger in 1.5 years - Here's what I learned

WinXP655 — Sun, 26 Jul 2026 16:53:32 +0000

When I started writing QuickChat, I was only 15.

First version was just 90 lines of pure console code.
Now - it is 900+ lines with a full GUI, custom protocol and Windows 2000 up to 11 support.

And project is still maintained.

Here's the story of entire project.

Beginning: P2P Messenger 1.0

Screenshot of P2P Messenger 1.0

The project originally was named "P2P Messenger". First version released on 24 May 2025.

It was very simple prototype:

Console
TCP pipe
No GUI, no names, no sounds
No error handling

Just two computers exchanging text.

P2P Messenger 1.0g.

Screenshot of P2P Messenger 1.0g

The first graphical version appeared in May 2025.
But it was just a prototype, which gave starting point.

P2P Messenger 1.1

Screenshot of P2P Messenger 1.1

It was the first version with a real GUI. It was released on 27 May 2025

It had:

A proper window
Username based on computer name
User list

This version was no longer a prototype - it became a fully working messenger.

P2P Messenger 1.2 will be skipped because it was a minor update - replaced LISTBOX with EDIT

P2P Messenger 1.5

Screenshot of P2P Messenger 1.5

At this point, the project had grown into a proper messenger:

Sounds - join, leave, new message
Menu bar - Sesson, Help
Chat logging - now it can record chat and events
About dialog - every app needs at least one
Fonts - Tahoma for UI, Lucida Console for messages
Icon - because it became proper messenger, it got its icon.

Also it finally got:

Removing trailing whitespaces and newlines
Join and leave message

But there was one big problem - it lacked error handling at all.
As result, the app just would crash or continue as is.

P2P Messenger 2.0 also skipped because it was mostly empty update - just changed header to "winsock2.h" and nothing else.

Some early dates were lost during migration from one PC to another (NTFS -> FAT32 flash drive). The code survived. The timestamps didn't.

P2P Messenger 2.1 Beta

2.1 Beta was supposed to be the final, most complete version.

It had a lot of new features and new utility "Server Stop" (it existed only as part of P2P Messenger 2.1). Sounds good, right?

Actually, no - it was a mess.
The code was hard to navigate, features was on top of each other, error handling was inconsistent. Architecture was filled with a problems.

Every time I was adding something new, something else would be broken.

It worked, but barely.

Chat2

After P2P Messenger 2.1 Beta, I renamed the project to Chat2.
The only version was from 2 June 2025

It was intended to be a fresh start and make it more secure.

It had several changes:

Added security dialog - users now could accept or reject connection.
Fonts was simplified to just Tahoma.
Tried to make code cleaner.

But it didn't helped - code still was messy. Adding features didn't fixed broken foundation.

The Legacy: WinP2P and WinChat

After failed Chat2, the project was renamed again - WinP2P.

It had a lot of small updates:

Added error handling
Changed port from 8888 to 50000 (to avoid conflicts with HTTP proxies and servers)
Tried to implement tray notifications (failed)
Switched fully to WinSock 2.0

Screenshot of WinChat

Then came WinChat - a much simplified version:

Removed user list
Removed window flashing (will return later)

But it didn't last long. After several hours it got its final name - QuickChat.

QuickChat Legacy (November 2025 - January 2026)

At this time, QuickChat was growing very fast:

November 2025:

Implementation of XOR
Window resizing

December 2025:

Buffer extended to 4096 characters
Added Close Connection (for server only)
Logging became optional
Millisecond precision in logs

January 2026:

XOR became optional
Protocol selection dialog
Sound, Always on Top, Window Flash toggle
Computer Info, Clear Chat

Legacy era ended on 6 January 2026.

QuickChat Modern (January 2026 - Present)

Screenshot of latest QuickChat

Just hours after Legacy ended, Modern began.

It added a lot of features:

Separated ports: QCS (65501), QC (65502)
QC/QCS protocol shows in title bar
Protocol got its marker: QC:PCNAME\0
Ping command: QCPING/QCPONG
Full Unicode support

But at that time, it was still private.

The first public release happened on 12 July 2026.
16 July 2026 - source code was opened.
18 July 2026 - security fixes.
26 July 2026 - build system update.

MicroChat - Minimalistic framework

Screenshot of MicroChat

Alongside QuickChat, I was building MicroChat - a lightweight framework based on the same engine.

It was QuickChat but without extras:

No XOR
No protocol
No sounds
No flash
TCP and basic GUI

Sometimes you don't need all the features - just need to exchange text over network.

Initial release was on 15 January 2026, but it still was private.
First public release was on 14 February 2026.
18 July 2026 - full Unicode and dropping Windows 9x support.
26 July 2026 - minor build system update.

MicroChat was also the testing ground for features later added to QuickChat.

What I learned

Document everything - even if no one reads it, it still worth documenting
Be honest - XOR is obfuscation, not encryption
Trust yourself - you don't need permssion to start something

Links

QuickChat: https://github.com/WinXP655/quickchat
MicroChat: https://github.com/WinXP655/microchat
P2P Messenger (archive): https://github.com/WinXP655/p2pmsgr
QuickChat Full Changelog: CHANGELOG.md
MicroChat Full Changelog: CHANGELOG.md

Questions?

If you have questions, you're welcome to ask me.

DEV Community: WinXP655

I built a LAN messenger using C when I was 15. 1.5 years later, it's still alive.