modbus-webui (beta)

Single-file Modbus workbench — profiles, name tables, shortcuts.


What it is

A browser-based UI for Modbus devices. Runs fully client-side via the Web Serial API and modbus-webserial. No install required to use the app; optional CLI for quick start. \
Built with Svelte and shadcn.

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Quick start

$3

$3

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``bash


serve the packaged HTML immediately

npx modbus-webui start

or write the HTML to your cwd, then serve it

npx modbus-webui init
npx modbus-webui serve

options:

--port=5173

init [filename] [--force]

serve [filename] [--port=...]

`

You can also download the single modbus-webui.html file and open it directly in a supported browser.

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Features

* Read / write coils and registers
* Profiles: per-device settings + saved write shortcuts
* Name tables: global sets covering coils, discrete inputs, holding and input registers
* Shortcuts: one-click saved writes
* Local persistence: everything stored in your browser

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Basic usage

1. Click Connect and choose your serial port.
2. Set port parameters (baud, parity, etc.) and click Open.
3. Use Read / Write panels to operate coils and registers.
4. Save frequent actions as Shortcuts and run them from the Shortcuts panel.
5. Use Name Tables to label addresses; Profiles keep device-specific setup.

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Concepts

$3

* Hold your selected name-table set, connection settings, and write shortcuts.
* Changes apply immediately to the active profile. Switching profiles does not disconnect the port.

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* Stored globally; any profile can select a set to use.
* Cover all four areas: coils, discrete inputs, holding registers, input registers.
* Names are linked to addresses (enter as decimal or hex). Edit via the Name Tables modal or copy/paste a full set as JSON.

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* All data is kept as a single library and saved to localStorage (auto or manual save).
* The stored data is versioned to allow future migrations.

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Browser support

* Requires Chromium-based desktop browsers with Web Serial enabled.
* You grant port access per session; after reload you may need to select the port again.
* The app will show a notice if Web Serial isn’t available.

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Development

`bash


install

npm i

dev

npm run dev

build (emits dist/modbus-webui.html)

npm run build
``

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