iperf3 with a web interface and a scheduler.

iperf3 is the standard tool for measuring throughput between two points, but it is a command-line program: every measurement is a snapshot in a console window. i-Tracker turns it into continuous measurement: on a schedule, against any number of servers, with stored history in the browser.

Explore i-Tracker Documentation

01iperf3From the command line to the browser

The same parameters, without a console.

A typical iperf3 measurement looks like this: four parallel connections, ten seconds, download from the server to your own machine:

iperf3 -c iperf.example.net -p 5201 -P 4 -t 10 -R

In i-Tracker you set this once per server. It runs the measurement at the chosen interval, keeps the result and shows the history over an hour, a day, a week or a month.

Protocol: TCP for throughput, UDP additionally with jitter and packet loss for voice and video, with a selectable UDP bandwidth.
Direction: Download, upload or both at once.
Duration: 1 to 300 seconds, plus parallel connections for fast lines.
Schedule: A separate interval per server, every 30 minutes by default. Only one measurement runs at a time, so measurements do not distort each other.
Live: During the measurement the values per second, afterwards all details and the raw iperf3 output.

02Test serversWhat you measure against

Your own endpoints or public iperf3 servers.

A browser speed test usually measures to the nearest server of your own provider. It is more meaningful to measure to where your data really goes: the data center, the branch office, the cloud region. iperf3 runs there as the endpoint (iperf3 -s), or you pick a public server from the built-in list.

Profiles: Per target a name, address, port (usually 5201) and its own test defaults, can be switched off temporarily.
Public: Public servers are often heavily loaded. Measure there rarely and with few parallel connections.
Route: Optionally a traceroute after every measurement, see traceroute on a map.
Installation: Windows as a service, Linux with Docker. If iperf3 (3.17 or later) is missing, i-Tracker installs it at the push of a button, on Windows via winget.
Guest view: Without sign-in a read-only view of the results, for example for a screen in the office. Can be switched off.

03FAQFrequently asked questions about iperf3 and i-Tracker

Is there a GUI for iperf3?

iperf3 itself has none. i-Tracker is a web interface for it: it runs iperf3 on a schedule, stores the results and shows them as history in the browser. It is free and open source (AGPL-3.0).

Does i-Tracker run on Windows?

Yes, as a Windows service. It installs iperf3 via winget on request. On Linux there is a Docker template whose image already contains iperf3 and traceroute.

How do I measure internet speed continuously?

With measurements at a fixed interval against the same endpoints. i-Tracker measures per server, for example every 30 minutes, and shows the history over days and weeks. That reveals whether performance drops at certain times of day or to certain destinations.

TCP or UDP: what should I measure?

TCP shows throughput as file transfers and backups experience it. UDP additionally shows jitter and packet loss, which matter for voice and video calls. With UDP, specify the bandwidth, otherwise iperf3 only sends 1 Mbit/s.

Can I measure against public iperf3 servers?

Yes, i-Tracker includes a list. Public servers are often busy, though, and only run one measurement at a time. For reliable values your own endpoint is better, for example a small server in the data center.