Draw OT and ICS network topologies in your browser
OTDraw is a purpose-built diagram editor for operational technology and industrial control networks. Instead of fighting a general-purpose drawing tool, you get a palette of OT assets like PLCs, RTUs, HMIs and historians, zone containers that match how OT networks are actually segmented, protocol labels on every link, and one-click PlantUML export for version-controlled documentation.
How to use it
- Pick an asset type from the palette and click the canvas to place it.
- Draw links and label them with the protocol in use, like Modbus or OPC-UA.
- Group devices into zones, for example a process control network behind an industrial firewall.
- Export to PlantUML to keep the diagram in version control next to your documentation.
Methodology and sources
The editor runs entirely in the browser with no server round-trips, so diagrams never leave your machine. The asset palette covers the devices that appear in real OT networks, and the zone and link model follows common industrial segmentation practice, where an enterprise IT boundary and an industrial firewall separate the control network. PlantUML export produces text-based diagrams that can be reviewed, diffed and stored alongside the runbooks they illustrate.
FAQ
Do my diagrams leave my browser?
No. The editor is fully client-side. Export produces a PlantUML text file that you save yourself.
Can I use it for architecture reviews?
Yes. Zone containers, protocol-labeled links and OT-specific node types are designed for review sessions where accuracy matters.
What formats can I export?
PlantUML text for version control, plus the browser's own print-to-PDF for slide decks.
Does it need an account or install?
No account, no install, no server. It is a single page that runs offline.
Can this be adapted for my organization's asset naming scheme?
Yes, custom builds can add your device types, naming conventions and zone templates. Ask through the contact form.
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Need this tuned to your data?
This tool runs on public data. We build the same kind of thing on your own data, wired into your systems.