Custom Workflow v/s Custom Action v/s Custom API Explanation
Custom Workflow v/s Custom Action v/s Custom API
| Custom Workflow | Custom Action | Custom API | |
| Private Scope | Not Applicable | No Support | Supported |
| API Type | Not Applicable | No Support – Always Action | Supported – Function/Action |
| Code First Approach | Not Applicable | No Support | Supported |
| Data Types of parameters | More Data Types | Less Data Types | More Data Types |
| setup | Using dot net code with VS | With UI | With UI |
| Calls | Can be called from another OOB WF | Can be called from Power Automate or Third-party using Web API | Can be called from Power Automate or Third-party using Web API |
| Pipeline message | Do not create a messaging step in pipeline | Creates a custom message | Creates a custom message |
| Parameters defined | In code | In UI | In Solution Component, PRT, Power Shell, WEB |
| Plugin Call | No Plugin Call | Can call a Plugin | Can Call a Plugin |
| Action Steps | Only code action steps allowed | Supports OOB action steps | DO not support OOB action steps |
| Sync/Async | Depending on calling WF | Synch/Async | Sync/Async |
| WF calls | Can be called from WF | Can be Called from WF | Can be called form WF with feature enable |
Read Microsoft Article for more info on the difference between Custom Action and Custom API here https://learn.microsoft.com/en-us/power-apps/developer/data-platform/custom-actions#compare-custom-process-action-and-custom-api
Action v/s Function in Custom API
