OpenTrace: a cross-platform GUI for NextTrace route tracing

What OpenTrace adds on top of the NextTrace CLI

Traceroute output on a terminal is a wall of IP addresses and millisecond columns. Reading it means mapping each hop to a network by hand, and comparing two runs means scrolling. OpenTrace exists to put that output on a map and in a table you can sort, and to expose the NextTrace parameters as labelled fields instead of flags. The README describes it as an open source visualized route tracing tool, and the feature list names a cross-platform native GUI with Windows WPF, Linux GTK and a macOS app bundle.

The audience is fairly narrow. This is a desktop diagnostic tool for people who already know what a hop is and want to see where traffic leaves one network and enters another. It is not a monitoring agent, it does not run headless, and nothing in the repository layout suggests a server component. If you need continuous per-host latency graphs, this is the wrong shape of program. If you occasionally need to answer "why is this route slow from my laptop", the GUI is the point.

How OpenTrace talks to NextTrace, and what it does not do itself

The credit section is explicit: OpenTrace uses NextTrace as the backend. That single sentence explains most of the architecture. OpenTrace is a shell around an external executable. It collects parameters from the UI, launches NextTrace, and renders what comes back. The README's note about building from source confirms the relationship: when preparing a redistributable archive you also download the matching NextTrace executable and place it beside OpenTrace, or let the user select an external NextTrace executable in the application settings.

That design has consequences worth stating plainly. The quality of the trace depends on the NextTrace build you pair with OpenTrace, not on OpenTrace's own version number. A stale NextTrace will produce stale behaviour inside a current GUI. The MTR feature follows the same pattern: the README says it uses native NextTrace MTR with v1.5.2 and later, and silently falls back to a compatibility implementation when that is unavailable. Silent fallback is convenient but it means two users on the same OpenTrace release can be running different MTR code paths without any visible indication.

Two capabilities sit outside NextTrace. On Windows, TCP and UDP traceroute require Npcap, which the README asks users to download and install separately. And the Cloudflare-based verification flow for NextTrace API v4 tokens is integrated into OpenTrace, with the README tying it to NextTrace v1.7.0 or later. Token handling therefore lives in the GUI, while token consumption lives in the backend.

Installing OpenTrace and running a first trace

The README points at three distribution routes: the official website, the GitHub releases page, and for Linux either Flathub or the Arch User Repository package opentrace-bin. There is no package manager command documented for Windows or macOS, so on those platforms you download an archive and unzip it. The README says to unzip and run OpenTrace, and on macOS the app bundle is the artifact.

If you compiled OpenTrace yourself, the README adds a step the packaged builds handle for you: place NextTrace in the OpenTrace directory or somewhere on PATH, or point OpenTrace at it manually. macOS users are told to specify the path manually, which is the recommended option there.

Building from source starts with a restore. The README gives this command from the repository root, and it needs the .NET 8 SDK:

dotnet restore OpenTrace.csproj

Platform builds then differ. Linux uses a self-contained net8.0 build, and the README shows the x64 and arm64 runtimes separately:

dotnet build OpenTrace.csproj --runtime linux-x64 --configuration Release --self-contained -f net8.0

On Windows the target framework is net48 or net481 depending on architecture, and the build is not self-contained:

dotnet build OpenTrace.csproj --runtime win-x64 --configuration Release --no-self-contained -f net48

Once the app is running, the first useful action is a trace to a host you control, so you can compare the hop list against something you already know. The README also documents launching a trace from the command line, which is the fastest way to confirm the NextTrace pairing works before you trust the GUI. The documentation does not spell out the CLI syntax, so check the in-app parameter descriptions the feature list mentions. If the trace returns nothing, the first thing to check is whether NextTrace is reachable: either beside the binary, on PATH, or set explicitly in the settings.

Where OpenTrace stops being the right tool

The dependency on an external executable is the main limitation, and it is not cosmetic. If NextTrace is missing or the wrong architecture, OpenTrace has nothing to draw. The README treats placing NextTrace as a manual step for self-compiled builds, which means the failure mode is a GUI that launches and then cannot trace. That is a worse experience than a CLI that prints "command not found".

Windows users hit a second dependency. TCP and UDP traceroute need Npcap installed separately, and the README frames it as a requirement rather than an option. Without it, those modes are unavailable, and the ICMP path is what remains. That distinction matters because TCP tracing is often the only way to see past a filter that drops ICMP.

The silent MTR fallback is a third edge. The README states that OpenTrace uses native NextTrace MTR with v1.5.2 and later and falls back to a compatibility implementation when unavailable. Nothing in the README says the UI distinguishes the two, so if MTR numbers look different between two machines, the NextTrace version is the first thing to compare. Finally, this is a desktop application by construction. There is no documented headless mode, no service unit, and no output format for piping into another system. For scheduled measurement across a fleet, a plain NextTrace invocation in a script is the more direct route.

OpenTrace against running traceroute or NextTrace directly

The honest alternative is NextTrace on its own. It is the same engine, minus the GUI, and the README's own build notes make the point that OpenTrace depends on it. If your work is a single trace from a terminal, or a loop over twenty targets written into a shell script, NextTrace gives you that without a window, without a .NET runtime, and without the Npcap requirement on Windows unless you specifically need TCP or UDP probes. The difference is not capability but interface: OpenTrace trades scriptability for a map, sortable hop tables and labelled parameter fields.

The other comparison people reach for is the classic traceroute and mtr pair shipped by most Unix systems. Those are separate implementations with their own probing behaviour, not wrappers around NextTrace. Choosing between them is choosing between two different tracer implementations, and the hop lists will not always agree. OpenTrace's own README does not position it against those tools, and it would be overreach to claim it replaces them. What can be said is narrower: OpenTrace is the graphical option within the NextTrace family, and the NextTrace family is what it depends on.

Licence, releases and the cost of keeping up

OpenTrace is released under GPL-3.0. For anyone redistributing a build, that licence carries obligations that a permissive licence would not, and the repository already reflects the practical side of it: there is a THIRD-PARTY-NOTICES.md at the top level alongside LICENSE.txt. If you bundle OpenTrace with NextTrace, you are shipping two projects under their own terms, and the release workflows under .github/workflows are the README's stated reference for how the published archives are assembled. This is not legal advice; read the licence text and the notices file before you ship anything.

On maintenance, the repository is not archived and the last push was on 2026-08-06, which is recent enough that the project is being worked on. Releases are less frequent: v1.5.2 on 2026-07-26, v1.5.1 on 2026-01-01, and v1.5.0.0 on 2025-12-24. The upgrade cost has two axes. OpenTrace itself is a desktop app you replace wholesale from the releases page or, on Linux, through Flathub or the AUR package. NextTrace is the second axis, and the README ties specific behaviour to specific NextTrace versions, v1.5.2 for native MTR and v1.7.0 for the API v4 token flow. Upgrading one without the other can leave you on the compatibility path without noticing.

Editorial conclusion

OpenTrace suits engineers who want MTR-style visual tracing on a desktop without memorising NextTrace flags, and who accept that NextTrace is a separate binary they must supply. It is the wrong tool for unattended servers, for CI pipelines and for scripted multi-hop measurement across many hosts, where the NextTrace CLI or a purpose-built probe is a better fit. Before adopting it, verify three things on your own machine: that the NextTrace executable is discoverable, that Npcap is installed if you intend to use TCP or UDP tracing on Windows, and that the NextTrace API v4 token setup completes, since the README ties that flow to NextTrace v1.7.0 or later.

Frequently asked questions

Official sources

1. Archeb/opentrace on GitHub
2. License: GPL-3.0
3. Project website
4. README
5. Releases