MultimonCast is a lightweight Go-based wrapper around multimon-ng that lets you view and share decoded signal data over HTTP in real-time.

It acts as a bridge between any audio or baseband source (such as RTL-SDR, rtl_fm, or rtl_tcp) and a web interface, making multimon-ng output available remotely or in other applications.

MultimonCast:

• Runs multimon-ng in the background.
• Captures its decoded output (text lines).
• Serves that output live via a simple HTTP endpoint.
• Keeps the latest 1000 lines of decoded text in memory.
• Can be accessed from a browser, curl, or other applications.

This means you can feed MultimonCast any signal stream multimon-ng supports, and then view the decoded messages from anywhere on your network.

Start by piping audio or baseband data into MultimonCast.
It works just like multimon-ng, but adds a live HTTP feed.

Example:

nc localhost 7355 | ./multimoncast -t raw -a AFSK1200 -

This example:

• Connects to an RTL_TCP server on localhost:7355.
• Pipes the raw baseband data to MultimonCast.
• Tells MultimonCast to decode AFSK1200 (typical for APRS).
• Starts a local web server on port 8585.

Once running, open your browser or use curl:

curl http://localhost:8585/

or visit:

http://localhost:8585/

You’ll see a live text feed of decoded messages from multimon-ng, such as pager data, DTMF tones, AFSK telemetry, etc.

MultimonCast passes all arguments directly to multimon-ng. That means any valid multimon-ng option can be used.

Examples:

# Decode POCSAG at 1200 baud
nc localhost 7355 | ./multimoncast -t raw -a POCSAG1200 -

# Decode DTMF tones from microphone input
arecord -r 22050 -f S16_LE -t raw | ./multimoncast -a DTMF -

# Decode FLEX pager traffic
nc localhost 7355 | ./multimoncast -t raw -a FLEX -

• The web interface shows only the last 1000 lines of decoded output.
• You can run MultimonCast as a background service to share decodes on a LAN.
• Use tools like curl, wget, or tail -f to consume data from the HTTP output for integration with other software.

You could run MultimonCast alongside an SDR stream:

rtl_fm -f 144.390M -s 22050 -g 35 - | ./multimoncast -a AFSK1200 -

Then, on another machine:

curl http://your-pc-ip:8585/

Instant live APRS or telemetry feed — no need for SSH or local access.

MultimonCast turns any multimon-ng decode into a live web feed — perfect for monitoring radios, pagers, or telemetry systems from anywhere.