Serial Communication Tool - Web Serial

Browser-based serial terminal using Web Serial API. Connect to COM ports, send/receive HEX/ASCII, run macros, log to TXT/JSON/CSV.

Serial Communication Tool is a browser extension that communicates with your PC's COM ports (serial devices) using the Web Serial API. No dedicated software to install — do serial communication entirely in Chrome, as an alternative to Tera Term or PuTTY. Use cases: - Embedded development debugging (Arduino / ESP32 / STM32 / Raspberry Pi Pico) - Configuring and maintaining industrial equipment (RS-232C, and RS-485 via a USB-RS485 adapter; 2-wire half-duplex supported) - Checking IoT device behavior - Sending/receiving Modbus RTU, AT commands, and custom protocols Features: - Serial settings — baud rate, data bits, parity, stop bits, flow control, and RTS/DTR signals - Modbus RTU master — FC03/04 (read registers) and FC06/16 (write registers); specify slave ID, address, and values, then send/receive and view the result - Auto-responder — automatically replies when received data matches a rule; lets the tool emulate a responding (slave) device, handy for loopback testing - Strict ASCII (7-bit) mode — reliable communication with ASCII devices (non-ASCII shows as "." on receive, and sending non-ASCII is blocked) - Send/receive log — timestamped log with file export (TXT / JSON / CSV), filtering, and auto-save on disconnect - Send history — recall past commands with the ↑ / ↓ keys (up to 50) - Quick commands — one-click sending of frequent commands, reorder by drag & drop - Macro automation — automated sequences with SEND / WAIT / RETRY and response waiting - Checksum helper — automatically append a checksum to sent data (per-command override) - Regex alerts — beep notification on pattern match - RX / TX rate display — real-time throughput monitoring - Response time measurement — latency from command send to response - HEX binary send — send arbitrary binary in hexadecimal - Profile management — save and share connection settings (import / export) - Multilingual — Japanese, English, Chinese, Korean, German, French, Spanish, Portuguese * RS-485 is used via a USB-RS485 adapter. Local-echo discard for 2-wire (half-duplex) is also supported (Modbus). Permissions: uses only "storage". No network communication whatsoever.