tcpdebug

A lightweight WinForms HTTP debug message receiver. Run it on your local machine to capture and inspect debug messages sent from browser applications or web services over HTTP.

Prerequisites

• .NET 10 SDK (or later)
• Windows (WinForms dependency)

Build

dotnet build

Run

dotnet run

This opens the tcpdebug window. Click Start to begin listening for messages (default port 5000).

Sending debug messages

POST to /debug with either JSON or plain text.

JSON

fetch("http://localhost:5000/debug", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ message: "User clicked checkout button" })
});

Plain text

fetch("http://localhost:5000/debug", {
  method: "POST",
  body: "Something happened"
});

curl

curl -X POST http://localhost:5000/debug -H "Content-Type: application/json" -d "{\"message\": \"hello from curl\"}"

C# / HttpClient

await httpClient.PostAsJsonAsync("http://localhost:5000/debug", new { message = "hello from backend" });

Features

• Start / Stop — toggle the HTTP listener on and off
• Port configuration — change the listen port before starting
• Auto-scroll — follows new messages as they arrive (toggleable)
• Sender IP — each message shows the remote IP address
• Save session — export the current session to a .txt transcript file
• Load session — reload a previously saved transcript
• Clear — wipe the current session with confirmation

Transcript format

Saved transcripts are tab-delimited text files:

tcpdebug session - 2026-02-10 14:32:05
============================================================
#1	2026-02-10 14:32:05.123	192.168.1.5	User clicked checkout button
#2	2026-02-10 14:32:06.456	10.0.0.1	Cart total: 42.00

These files can be reloaded into tcpdebug via Session > Load.

Health check

GET http://localhost:5000/ returns tcpdebug is running when the listener is active.