No. Modbus Poll by Witte Software (modbustools.com) is a paid, commercial tool starting at $129 per license, with a 30-day free trial that disconnects every 10 minutes. It is not the same product as the unrelated modbuspoll.com app.

Is qModMaster still maintained?

The official qModMaster repository (GPL-2.0, Windows and Linux) has not had a code commit since January 2022, based on its GitHub history.

Does mbpoll have a graphical interface?

No. mbpoll is a command-line tool (GPL-3.0) with no GUI, built for scripting and automation rather than interactive use.

Free Modbus TCP Client Comparison

Modbus Connect vs. Modbus Poll, qModMaster, Radzio Modbus Master Simulator, and mbpoll — the facts, including where each tool beats us.

We built Modbus Connect, so we're not neutral. This page exists because most "comparisons" of Modbus tools are thinly veiled ads that never mention a competitor's real advantages — which makes them useless for anyone actually deciding what to install. Every claim below is checked against the vendor's own site, GitHub, or release history as of August 2026, and we've flagged the areas where established or actively-maintained alternatives are the better choice. No benchmarks here are ours — we haven't run controlled performance tests against these tools, so we don't claim to know which is fastest.

Tool	License	Platforms	Interface	Last updated
Modbus Connect	Free (beta), proprietary	Windows, macOS, Linux	GUI	Active (v0.6.0, 2026)
Modbus Poll	Paid, from $129/license (30-day trial)	Windows only	GUI	Active, 20+ years on market
qModMaster	Free, GPL-2.0	Windows, Linux	GUI	Dormant since Jan 2022
Radzio Modbus Master Simulator	Free, permissive	Windows only	GUI	Dormant since Oct 2017
mbpoll	Free, GPL-3.0	Windows, macOS, Linux	Command-line only	Active, 2026

Modbus Poll (Witte Software)

Modbus Poll from Witte Software (modbustools.com) is a commercial Windows tool that has been sold for over two decades. It is not free: pricing starts at $129 for one to two licenses, dropping to $109/license at volume, and the 30-day trial disconnects every 10 minutes. There is also an unrelated product also named "Modbus Poll" from a different developer at modbuspoll.com — don't confuse the two.

Where it's genuinely better

20+ years on the market with a large, established user base — far more track record than any newer tool
Deeper feature set: 28 display formats, Excel/OLE automation, a scripted "Test Center," and 23+ supported function codes
Paid support and maintenance included with license

Trade-offs

Not free — $129+ per seat after the trial expires
Windows only, no macOS or Linux build
Trial connections auto-disconnect every 10 minutes

qModMaster

qModMaster is a free, open-source (GPL-2.0) Qt-based Modbus master with a built-in bus monitor for inspecting raw traffic. It's a legitimate, no-cost option for Windows and Linux — but the official repository has had no code commits since January 2022, so treat it as a stable snapshot rather than an actively developed project.

Where it's genuinely better

Open source (GPL-2.0) — the code is auditable and self-buildable, unlike closed-source alternatives
Built-in bus monitor shows raw hex request/response traffic, useful for low-level debugging
No cost, no license restrictions

Trade-offs

No commits to the official repo since January 2022
No official macOS build
No built-in data logging or charting

Radzio Modbus Master Simulator

Radzio Modbus Master Simulator is a free Windows tool that markets itself as an alternative to commercial software like Modbus Poll. It supports multiple simultaneous Modbus TCP and RTU connections with several data-type displays. Its official page lists its last update as October 28, 2017, with no public update since.

Where it's genuinely better

Free with a permissive license and no trial limitations
Simulates multiple master/slave connections at once with saved connection profiles

Trade-offs

No public update since October 2017
Windows only
No data logging, scanning, or charting

mbpoll

mbpoll is a free, open-source (GPL-3.0) command-line Modbus client for Windows, macOS, and Linux, including ARM boards like Raspberry Pi. It's the most actively maintained alternative on this page, with commits and releases landing as recently as February 2026. It has no graphical interface by design — it's built for scripting and automation, not interactive use.

Where it's genuinely better

Actively maintained — the only tool here with 2026 commits and releases
Scriptable from the command line, so it drops straight into CI pipelines, cron jobs, and shell automation — something a GUI application like Modbus Connect isn't built for
Runs on ARM boards (Raspberry Pi, Armbian) in addition to desktop platforms

Trade-offs

No GUI — every read/write is a manual command
No built-in scanner, charting, or file logging

Where Modbus Connect is honestly behind

Track record: Modbus Connect is a beta (v0.6.0) released in 2024. Modbus Poll has over two decades of production use behind it — if you need a tool with a long, proven history, that history doesn't exist for us yet.
Code signing: our macOS build is unsigned, so Gatekeeper blocks a normal launch and requires a manual workaround. Signed alternatives don't have this friction.
No scripting interface: Modbus Connect is a GUI-only application. If you need to poll a device from a shell script, cron job, or CI pipeline, mbpoll is the better tool — we don't have a command-line mode.
Not open source: qModMaster and mbpoll publish their full source code under GPL. Modbus Connect's source isn't published, so you can't audit or self-build it the way you can with those two.

If a GUI scanner, monitor, and logger in one app fits your workflow

Modbus Connect is free during development for Windows, macOS, and Linux — unlimited devices, no trial timer.

Download Modbus Connect Free