When it comes to modern data workflows, REST APIs are one of the most flexible and widely adopted methods of integrating different systems. Whether you’re working with enterprise software, cloud services, or custom applications, REST provides a lightweight way to exchange data.
In this post, we’ll explore how OPC Router’s REST Client plug-in simplifies connection to RESTful endpoints. We’ll then walk through a practical demonstration using Software Toolbox’s Data Caster product, covering: A step-by-step demo of configuring the REST Client in OPC Router to collect data from an API and display that data with Data Caster.
By the end, you’ll see how REST fits neatly into your industrial data architecture, giving you a flexible bridge between OT and IT systems.
What is a REST API, really?
REST or REpresentational State Transfer is a type of protocol, of sorts, that software can use to communicate with other software generally over the internet. And an API is an Application Programming Interface. Like any protocol, RESTful APIs or web services define a set of rules for sending and receiving data and an accepted format of what those sends and receives should be.
At its core, REST is simple:
- It uses common HTTP methods like GET, POST, PUT, PATCH, and DELETE to read, send, update, or remove information.
- Data is exchanged in a structured format, most often JSON (JavaScript Object Notation), though XML and others are possible.
- REST is stateless, meaning every request contains all the information the server needs — no lingering session states or dependencies between requests.
Why does this matter in an industrial automation context?
Traditionally, OT systems communicate using proprietary or specialized protocols such as OPC, Modbus, or Ethernet/IP. These protocols are perfect for control systems but not always well-suited for connecting with cloud applications, databases, or enterprise systems. REST bridges that gap by providing a universal language that nearly every modern IT or business application understands. This means you can:
- Send machine data directly to a cloud analytics service.
- Pull recipe data from an ERP or MES system into the shop floor.
- Integrate with SaaS platforms for reporting, maintenance, or even collaboration tools.
In short, REST is the glue that connects your plant floor with the broader digital ecosystem.
How to Integrate REST Web Services with Your Control System
With REST being so widespread, the question becomes: how do you get your OT systems talking to it? That’s where the REST Client plug-in for OPC Router comes in.
The REST Client plug-in allows OPC Router to send and receive RESTful messages with minimal configuration — no custom coding required.
Key Features of the REST Client Plug-in
- Support for major HTTP methods: GET (read data), POST (send data), PUT (update data), PATCH (partial update), DELETE (remove data).
- Authentication options: Basic authentication, API keys, and bearer tokens can be configured directly in the client.
- Flexible request building: You can define request headers, query parameters, and JSON or XML payloads.
- Native JSON handling: Pair the REST Client with OPC Router’s JSON Read/Write objects to easily map variables into or out of JSON structures.
- Logging and monitoring: Every call can be traced and validated within OPC Router, making troubleshooting straightforward.
The best part? Because it’s integrated directly into OPC Router, the REST Client can be combined with any other plug-in — OPC UA, SQL databases, MQTT, SAP, and more — so REST becomes just another node in your data workflow.
See It to Believe It: Displaying Data with DataCaster
So far, we’ve focused on how OPC Router’s REST Client can send and receive data through REST APIs. But what if you want to make that data visible in real time — not just buried in logs or databases? That’s where DataCaster comes in.
What is DataCaster?
DataCaster is a lightweight visualization tool designed to take incoming data and present it on-screen in a clean, accessible way. Think of it as the bridge between your raw process values and the people who need to see them. Instead of operators, managers, or engineers digging through tables and reports, DataCaster makes key information instantly available through simple, configurable displays.
Because DataCaster is REST-enabled, you can use OPC Router’s REST Client to post or patch data directly into it. That means any source OPC Router can connect to — OPC UA servers, databases, MQTT brokers, even SAP — can be funneled into Data Caster for visualization with just a few configuration steps.
- This makes DataCaster the perfect companion when you want to:
- Highlight production KPIs on a big screen.
- Show live machine status or alarms to operators.
- Broadcast performance metrics to leadership in real time.
In the next section, we’ll walk through a hands-on example: sending live data from OPC Router into DataCaster via REST. You’ll see how easy it is to patch values into Data Caster’s display and immediately watch them update on screen.
Conclusion: Connect. Visualize. Simplify.
REST APIs have become the universal language for connecting modern systems — and with the REST Client plug-in for OPC Router, you don’t need to be a programmer to take advantage of them. Whether you’re exchanging data with cloud services, ERP systems, or custom applications, REST provides a fast, reliable, and flexible bridge.
By extending that power to DataCaster, you’re not just moving data — you’re making it visible where it matters most. From real-time KPIs to live machine status, DataCaster helps you put critical information right in front of the people who need it, when they need it.
The combination of OPC Router and DataCaster makes REST more than just a technical connector — it becomes a practical tool for improving operations, decision-making, and collaboration.
Ready to see it in action?
- Watch the tutorials above to learn how to configure OPC Router’s REST Client and start posting data to DataCaster.
- Explore how REST can fit into your own existing workflows.
- Contact our team to explore how REST can meet your needs.
