PUT /WinCC/REST/Tags/TagName
"Value": 80.0
For decades, Siemens WinCC has been a cornerstone of SCADA (Supervisory Control and Data Acquisition) systems in manufacturing, energy, and infrastructure. But traditional SCADA architectures often live in walled gardens—powerful, but hard to integrate with modern IT systems, cloud platforms, and custom dashboards.
Enter WinCC REST API.
With the rise of Industry 4.0 and IIoT (Industrial Internet of Things), the ability to expose process data via standard web protocols is no longer a luxury—it’s a necessity. REST APIs transform WinCC from a monolithic HMI into a data server ready to talk to anything from a React dashboard to an ERP system. wincc rest api
In this post, we’ll dive deep into:
The core idea is beautiful. The WinCC REST API allows external clients to:
No more DCOM port ranges. No more registry hacking. Just a simple HTTP endpoint, secured with authentication (often via WinCC user management or Windows auth). In a demo, a Python script with requests.get(‘http://wincc-server/api/tags/BoilerTemp’) works in seconds. PUT /WinCC/REST/Tags/TagName
This is revolutionary for:
The WinCC REST API does not use API keys or OAuth2 by default. It relies on Windows Integrated Authentication (Negotiate/NTLM) or Basic Auth (over HTTPS only for security).
The diagram below illustrates a typical deployment scenario: "Value": 80
External Client (Python, C#, JavaScript, Power BI, etc.)
│
│ HTTPS (JSON)
▼
┌───────────────────────┐
│ WinCC REST API │
│ (Web server built │
│ into WinCC Runtime) │
└───────────┬───────────┘
│ Internal process communication
▼
┌───────────────────────┐
│ WinCC Runtime │
│ (Tag Manager, Alarms,│
│ Archive, Security) │
└───────────┬───────────┘
│ Industrial protocol (S7, Profinet, etc.)
▼
┌───────────────────────┐
│ PLC / Field Devices │
└───────────────────────┘
Key components:
The WinCC REST API is an OPC UA–based RESTful interface that allows external clients to interact with a running WinCC project using standard HTTP methods (GET, POST, PUT, DELETE). It exposes:
Unlike older DCOM or OPC DA interfaces, REST uses JSON over HTTP/HTTPS—meaning any programming language (Python, JavaScript, C#, etc.) or tool (Postman, Node-RED, Power BI) can integrate without special COM libraries or Windows-only dependencies.
Note: The REST API does not replace WinCC’s internal OPC UA server. It acts as a higher-level, developer-friendly wrapper, often simplifying authentication and data formatting.