Introducing i3x-portal

An open sandbox for OPC UA over i3X REST

If you have ever tried to compare how i3X and OPC UA describe the same address space, the honest first step used to be: stand up your own server, then wire up an i3X REST layer, then start your client. Not a hard sequence, but three steps between you and the actual question you wanted to answer.

i3x-portal.sterfive.io is now open. Sign up on the dashboard, spin up an instance, and you get a private i3X REST endpoint connected to a live OPC UA server. Free. Up to three hours per session, three concurrent per user. The signup exists so each session runs in a private area that is not shared with other users.

Screenshot of the i3x-portal dashboard showing an active instance connected to opcuademo.sterfive.com with request rate, latency, endpoint URL, and bearer token

What is on it

Each instance gives you a private REST endpoint scoped to your session and connected to an OPC UA server of your choice. The portal translates every browse, read, write, method call, subscription notification, and alarm event through node-i3x, so subscriptions on the OPC UA side and polling or streaming on the REST side both have something to observe.

Point the portal at your own OPC UA server and immediately see its AddressSpace over i3X REST. Paste an opc.tcp:// URL into the dashboard and the portal spins up a bearer-token-scoped REST endpoint that translates your server through node-i3x. Ideal for exploring existing OPC UA data through REST tooling, or for verifying i3X conformance of a server you are building.

Don't have a server handy? We provide one at opc.tcp://opcuademo.sterfive.com:26541, reachable from any OPC UA client (UaExpert, opcua-commander, your own code). It ships preloaded with representative content, including companion-spec examples: DI, Robotic, MachineVision, PackML, and Machinery.

What you can do with it

Three concrete use cases the portal is designed for.

Compare i3X and OPC UA side by side. Open the same node on both surfaces at once. Native OPC UA on opc.tcp://opcuademo.sterfive.com:26541, REST on the per-instance URL from your dashboard. Same underlying data, two representations. This is the fastest way to understand what an i3X mapping looks like at the wire, without any theoretical detour.

Prototype i3X client code without a local server. Point your REST tooling at the portal and iterate without a Node.js server running on your machine. Read, write, browse, and subscribe from a fetch call.

Explore correlation and matchability between the two models. Which OPC UA constructs have clean i3X representations? Which Variable shapes, DataType families, or ExtensionObject structures need explicit mapping choices? Where do the two models converge, and where do they diverge? These are the questions the portal is built to answer against real data rather than in prose.

What it is not

A production endpoint. State resets. Instances expire. Uptime is best-effort. Nobody's operational data lives on it. If a URL you rely on returns a 404 tomorrow, that is the sandbox doing its job.

We also do not track calls beyond aggregate load metrics. Analytics are cookieless, no request-body logging.

Why we run it

Two reasons.

First, the industrial interoperability community benefits from a shared point of reference. Initiatives such as CESMII (the Clean Energy Smart Manufacturing Innovation Institute) in the United States, umati (universal machine technology interface) in Europe under VDMA leadership, and the broader OPC Foundation ecosystem all rely on OPC UA as the substrate for cross-vendor data exchange. i3X is the modern REST-based surface on that substrate. When a working group, a vendor, or an engineer wants to test how does this specific pattern round-trip between OPC UA and i3X?, it is much easier to point at a live public server than to spin up private infrastructure or describe the scenario in prose.

Second, i3x-portal is a live feedback loop for node-i3x, the open-source Node.js bridge Sterfive maintains between OPC UA and i3X REST. When the portal breaks on a corner case, we find it before a customer does. When a request pattern gets popular, we make sure node-i3x handles it cleanly.

Related resources

Deep dives on the Sterfive blog:

i3X and OPC UA, a practical introduction: the 101 for anyone new to how CESMII's i3X sits on top of OPC UA.
i3X Meets OPC UA: When REST Meets Real-Time (Part 1 of 3): the shared information-modelling DNA between the two standards.
One API Call to Rule Them All, and Its Limits (Part 2 of 3): what i3X's decomposable asset model gets right, and where it hits its edges.
The Missing Safety Layer, and How to Bridge It (Part 3 of 3): the gaps i3X leaves (alarms, methods, events, security) and how node-i3x closes them.

Elsewhere:

node-i3x on GitHub: the open-source bridge that powers the portal.
The OPC Foundation reference site: the OPC UA specification suite, including the parts that describe the REST-based interoperability model behind i3X.
CESMII: the US Clean Energy Smart Manufacturing Innovation Institute, building the Smart Manufacturing Innovation Platform (SMIP) on top of OPC UA.
umati: the VDMA-led European standardisation effort for machine tool and manufacturing data, built on OPC UA and its companion specifications.

Try it

The portal is at i3x-portal.sterfive.io. Free. Signup creates your private area so instances stay isolated between users, no dark patterns beyond that. If you hit a bug, an interop question, or an OPC UA versus i3X shape mismatch that surprised you, we would like to hear about it. Reach out through the Sterfive contact page or open an issue on node-i3x.

The point of the sandbox is that the next time someone asks "how would i3X handle X in OPC UA?", you have a concrete answer ready in one browser tab.