Real-Time Data Monitoring
Live serial port data capture with configurable baud rates from 300 to 921600 bps. Stream RX and TX simultaneously in real time.
Monitor, analyze, and debug serial port communications in real time. View data in HEX, ASCII, or binary — directly in your browser with the Web Serial API. No software installation required.
Features
Everything you need to monitor, analyze, and debug serial device communication — directly in your browser.
Live serial port data capture with configurable baud rates from 300 to 921600 bps. Stream RX and TX simultaneously in real time.
Switch between ASCII, HEX, Binary, and signal chart views. Analyze raw bytes, decode protocols, or visualize signal waveforms.
Filter output using plain text or regex patterns. Highlight matches, isolate RX or TX traffic, and reduce noise in high-volume sessions.
Auto-decode incoming bytes into decimal, hex, binary, and ASCII columns. Ideal for debugging embedded firmware and serial protocols.
Export your complete session log as TXT, CSV, or JSON for offline analysis, compliance records, or sharing with your engineering team.
Per-line timestamps, session timer, live RX/TX byte counters, error tracking, and throughput rate for comprehensive session analytics.
Send data in ASCII, HEX, Binary, or Decimal format. Configurable line endings (CR, LF, CRLF) and a repeat/scheduler function for automated testing.
All processing happens locally in your browser. No data is uploaded to any server. Your serial communications remain completely private.
Zero setup. Open in any supported browser and connect immediately. Works on Windows, macOS, Linux, and ChromeOS via the Web Serial API.
How It Works
No drivers, no downloads — just open, configure, connect, and monitor your serial device in seconds.
Set your baud rate, data bits, stop bits, parity, and flow control to match your serial device's communication parameters.
Click "Connect" and choose your COM port or serial device from the browser's secure port picker dialog. Permission is sandboxed per session.
Watch incoming and outgoing data in real time. Switch between ASCII, HEX, and binary views, and use filters to focus on what matters.
Send test commands, trigger device responses, then export your full session log as TXT, CSV, or JSON for deep analysis.
A serial port monitor is a diagnostic software tool or web-based utility that intercepts, displays, and logs the data flowing through serial communication interfaces — commonly RS-232, RS-485, UART, and USB-to-serial adapters. Engineers, embedded developers, and QA professionals rely on a serial port analyzer to understand exactly what bytes a device transmits and receives, making it indispensable for firmware debugging, protocol reverse engineering, and hardware validation.
A serial device monitor extends the concept by tracking communication at the device driver level. It captures every read and write operation between the host operating system and the connected serial hardware — including Arduino boards, GPS modules, industrial PLCs, barcode scanners, and CNC controllers. This makes it vastly easier to identify misconfigured baud rates, byte framing errors, or corrupted packets before they cause product failures in the field.
A serial sniffer — also called a port sniffer or COM port monitor — passively taps the serial data stream without altering the communication. Traditional hardware sniffers require a physical null-modem cable and a second PC. Modern browser-based tools like this one use the Web Serial API to directly access the serial port from JavaScript, offering a lightweight, OS-independent alternative for quick serial data capture.
To monitor a serial port effectively: first match the baud rate (e.g., 9600, 115200), data bits (7 or 8), stop bits (1 or 2), and parity (None, Even, Odd) to your device's specification. Then connect with a serial terminal monitor, observe the raw data stream, and use hex view to inspect individual bytes. Toggle timestamps on to correlate events with system activity. Use the protocol decoder table to convert raw bytes into readable decimal, hex, and ASCII columns simultaneously.
Common uses for a serial port analyzer include: debugging Arduino sketches sending sensor data over UART; verifying NMEA sentences from GPS receivers; analyzing Modbus RTU frames from industrial sensors; checking AT command responses from GSM/LTE modems; monitoring RS-232 POS terminal traffic; and reverse engineering proprietary serial protocols from legacy hardware. The RS-232 monitor view with HEX and binary display makes it straightforward to identify start bits, stop bits, and control bytes within any custom frame structure.
Whether you're a professional embedded systems engineer, a maker debugging a microcontroller project, or a network technician auditing industrial device traffic, this free online serial port monitor gives you professional-grade visibility into your serial communications — right from your browser, with no installation required.
FAQ
Everything you need to know about the Serial Port Monitor Analyzer.
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