Glossary · Automation fundamentals, platforms and components
REST API
Also known as: RESTful API, RESTful web service
German: REST-API
In software engineering, a REST API is an application programming interface that follows the REST (Representational State Transfer) architectural style: resources are identified by URLs and manipulated with standard HTTP methods such as GET, POST, PUT and DELETE, typically exchanging JSON, with stateless requests.
- Automation components
In one sentence
A REST API exposes resources via URLs and standard HTTP methods, usually with JSON; common for MES, cloud and device integration.
Example
The MES creates a production order on the machine by sending a POST request with the order data in JSON to the machine's REST API.
Explained in context
Context cards connect this term with others to answer one question. Also in British English and German.
How it applies
- Engineering: REST APIs connect machines and edge devices to MES, ERP and cloud services. They are request-response and not suited for hard real-time exchange; use fieldbuses or real-time protocols for control data.
- Security: Every endpoint needs Authentication, authorization and encrypted transport (HTTPS). Disable unused APIs on devices.
- Documentation: API documentation, often as an OpenAPI description, lists endpoints, methods, parameters, response codes, error handling and versioning. Say which operations are safe to retry (Idempotency) and which change machine state.
REST vs. OPC UA
REST is a generic web style with no built-in information model. OPC UA brings a type system and an information model for industrial data, plus subscriptions. Many systems use both: OPC UA near the machine and REST toward IT systems.