SpeedBand

English | Русский

Diagnose whether your LAN is stable enough for realtime streaming. Measures latency, jitter and low-percentile throughput via browser - no install on the second device, no telemetry.

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Table of contents

• What SpeedBand does
• Why not iperf3?
• Use cases
• Results
• Quick start
• Connecting from another device
• Firewall
• Reading results
• Reports
• Recommended test conditions
• License

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What SpeedBand does

Runs a small HTTP server on your machine. Another device opens the page in a browser and runs a full test sequence:

1. Latency and jitter (/api/ping)
2. HTTP download throughput (/api/download)
3. HTTP upload throughput (/api/upload)
4. WebSocket realtime bitrate ladder (/api/ws)

All traffic stays inside the LAN. Results include a stable bitrate range with headroom levels, a quality label and a bitrate ladder breakdown.

Peak speed is not a safe streaming bitrate. SpeedBand uses low-percentile throughput, jitter and stall detection to estimate a safe operating range.

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Why not iperf3?

iperf3 requires installation on both devices and reports raw TCP throughput - not what matters for streaming.

SpeedBand runs as a single binary or go run. The second device only needs a browser. It measures what streaming actually uses: low-percentile throughput, jitter, stall detection and realtime bitrate stability across a stepped ladder. The output is a safe bitrate range with headroom levels, not just a peak number.

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Use cases

• Game and VR streaming (Moonlight/Sunshine, Steam Link, Air Link, Virtual Desktop, ALVR)
• NAS and media transfer checks
• Wi-Fi diagnostics
• LAN testing between PC, phone, tablet, laptop, headset or Steam Deck
• Finding whether peak throughput hides jitter, stalls or unstable low-percentile results

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Results

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Quick start

Download the binary for your platform from the Releases page and run it.

Windows: open a terminal in the folder with the downloaded file and run:

.\speedband-windows-amd64.exe

Linux:

chmod +x speedband-linux-amd64
./speedband-linux-amd64

macOS:

chmod +x speedband-macos-arm64   # Apple Silicon
./speedband-macos-arm64

# or for Intel Macs:
chmod +x speedband-macos-amd64
./speedband-macos-amd64

Open the LAN URL printed in the terminal on any device in the same network. No app install required on the second device - browser only.

Build from source

Windows:

go build -o speedband.exe ./cmd/speedband

Linux / macOS:

go build -o speedband ./cmd/speedband

Flags

Flag	Default	Description
--host	0.0.0.0	Listen address
--port	8080	Listen port
--open	false	Auto-open browser on start
--debug	false	Verbose logging

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Connecting from another device

1. Start SpeedBand on the host machine.
2. Use the LAN URL printed in the console, e.g. http://192.168.1.25:8080.
3. If .local hostname does not resolve, use the numeric IP.
4. On Meta Quest, open the URL in the headset browser.

The console prints all LAN IP candidates and marks the primary guess. Docker, VM and VPN adapters are filtered or flagged where possible.

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Firewall

If the page does not open from another device:

• Confirm both devices are on the same subnet.
• Windows: when prompted, allow access on Private networks. If not prompted, allow speedband.exe or go.exe in Windows Firewall for Private networks.
• Linux: ensure the port is open (sudo ufw allow 8080/tcp for UFW-based distros).
• macOS: allow incoming connections when prompted by the OS firewall dialog.
• Try the numeric IP instead of .local.
• Disable VPN temporarily.

SpeedBand listens on 0.0.0.0 by default. Run it only on a trusted local network.

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Reading results

Bitrate range levels:

Level	Meaning
Very safe	Conservative estimate with extra headroom
Recommended	Practical stable operating range
Risky upper	May work; showed reduced headroom or spikes
Avoid	Not recommended without real-app validation

Quality labels:

Label	Meaning
Excellent	Strong low-percentile throughput, low jitter
Good	Suitable for most realtime tasks
Acceptable	Usable; leave headroom
Risky	Unstable enough to require caution
Unstable	Not suitable for high bitrate realtime use

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Reports

• Download JSON - saves report on the client device.
• Save to server - sends report to the machine; saves a .log file in reports/ under the server working directory.

UI supports English and Russian. Reports use the language selected in the browser at save time.

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Recommended test conditions

• Connect the PC to the router with Ethernet.
• Use 5 GHz or 6 GHz Wi-Fi for the second device.
• Close active downloads, cloud sync and game updates.
• Run the Full stability test before choosing a high bitrate.
• Repeat 2–3 times; trust the more conservative result.

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License

MIT