> For the complete documentation index, see [llms.txt](https://next-docs.cloudio.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://next-docs.cloudio.io/workflow-rest-apis/wf_intro.md).

# Introduction

Workflow REST APIs can only be invoked from within a running workflow instance. It is secured by a token and the workflow node instance status. These APIs can only be invoked when the node instance is in the `Running` status.

![Sample Workflow Instance View](/files/-Mavfw18xP4G-wcty328)