Web Serial Terminal is a browser-based tool that uses the Web Serial API to communicate directly with serial devices (like Arduino, ESP32, Raspberry Pi Pico, STM32) through your computer's USB port — no software installation required. It works entirely in the browser, offering a full-featured serial monitor for debugging and interacting with microcontrollers.

The Web Serial API is supported in Google Chrome 89+, Microsoft Edge 89+, and Opera 75+. Firefox and Safari do not currently support the Web Serial API. You must also be on a secure context (HTTPS or localhost) for the API to be available.

Step 1: Connect your microcontroller via USB cable to your computer.
Step 2: Ensure the correct drivers are installed (CH340, CP210x, FTDI, etc.).
Step 3: Click the Connect button above and select your device from the browser's port picker dialog.
Step 4: Set the correct baud rate (commonly 9600 or 115200 for most boards; 74880 for ESP8266 bootloader).
Step 5: Start sending and receiving data!

Common baud rates: Arduino Uno/Nano — 9600 or 115200; ESP32 — 115200 (default); ESP8266 — 74880 (bootloader) or 115200; STM32 — 115200 or 921600; Raspberry Pi Pico — 115200. Always match the baud rate set in your firmware's Serial.begin() call.

DTR (Data Terminal Ready) and RTS (Request To Send) are hardware flow control signals. On many Arduino-compatible boards, toggling DTR triggers a reset, which is useful for entering bootloader mode. You can toggle these signals manually using the DTR/RTS buttons when connected.

Common reasons: (1) Your device isn't plugged in properly — check the USB cable and port. (2) Missing USB-to-serial drivers — install CH340, CP210x, or FTDI drivers as needed. (3) Another program (like Arduino IDE's Serial Monitor) is already using the port — close it first. (4) You're using an unsupported browser — switch to Chrome or Edge.

Yes. The Web Serial API requires explicit user permission via a browser dialog for each connection. No website can access your serial ports without your consent. The API is designed with security in mind — it only works on secure contexts (HTTPS) and the user must manually select the port each time.

LF (\\n) — Line Feed, common on Linux/macOS and many modern microcontrollers.
CR (\\r) — Carriage Return, used by some legacy systems.
CR+LF (\\r\\n) — Carriage Return + Line Feed, standard on Windows and many Arduino Serial.println() implementations.
Choose the line ending that matches what your microcontroller firmware expects.