SocketTester-Native TCP, UDP & Serial Port Testing Tool

SocketTester is a lightweight native Windows tool for testing TCP, UDP, and Serial/UART/USB-COM communication. It is made for developers, embedded engineers, network testers, and anyone who needs a simple terminal-style communication tester.

What It Supports

• TCP Client
• TCP Server with multiple clients
• UDP Client
• UDP Listener/Server
• Serial/UART/USB-COM ports
• Text sending and binary hex editor for raw byte payloads
• RX, TX, and system logs with timestamps — ASCII view and Hex viewer
• Send history, repeat send, search, copy, clear, and save log
• Multiple app windows using New Session

How To Use

Select the communication type from the Communication dropdown.

• TCP Client: enter IP and port, then click Connect.
• TCP Server: select Server mode and port, then click Connect. The app binds to 0.0.0.0 automatically.
• UDP Client: enter destination IP and port, then connect and send packets.
• UDP Server: select Server mode and port to receive from any sender.
• Serial: select COM port, baud rate, data bits, stop bits, parity, and flow control, then click Open.

Send Options

• ASCII tab: type text normally. CR / LF / CRLF append options, Enter-to-send, Repeat, and Clear-after-send all apply here.
• Hex tab: a built-in hex editor for sending raw binary payloads. Click any byte and type nibble by nibble (0–9, a–f), or click in the ASCII column and type characters directly. The buffer grows as you type; only the bytes you actually typed are sent — trailing placeholder bytes are excluded automatically.
• CR / LF / CRLF: append line endings (ASCII tab only).
• Enter: press Enter to send; use Ctrl + Enter for a new line.
• Repeat: send repeatedly using the interval value.
• Clear after send: clear the send box after a successful send.

Terminal Log

The log area has two tabs:

• ASCII tab — plain text log with TX, RX, and SYS entries.
• Hex tab — hex viewer showing every transmitted and received byte in three columns: Address, Hex, and ASCII. The address column width is configurable (hidden, 1-byte, 2-byte, or 4-byte).

[2026-05-29 17:14:13] TX  hello
[2026-05-29 17:14:15] RX  [COM7] response data
[2026-05-29 17:14:20] SYS Connected

• TX means sent data.
• RX means received data.
• SYS means connection or status message.

Hex Viewer Features

• Selection: click and drag to select bytes. Hold Shift and click or use Shift + arrow keys to extend the selection.
• Copy: Ctrl+C copies the selection as a space-separated hex string (e.g. 48 65 6C 6C 6F) if selected in the Hex column, or as plain ASCII text if selected in the ASCII column. The Copy toolbar button does the same.
• Find: the Find field searches the hex viewer’s ASCII byte content when the Hex tab is active. Each press advances to the next match with wrap-around.
• Save as binary: use Save Log and choose the .bin extension to save raw received bytes as a flat binary file, with no timestamps or formatting.

Other Notes

• Settings and history are saved locally in an INI file, not the registry.
• INI path: %LOCALAPPDATA%\SocketTester\SocketTester.ini
• Right-click the title bar and choose New Session to open another window.
• The app is native C++/MFC, uses worker threads, and does not require .NET.