# API calls

> Similarly to processing documents using Document Understanding or Intelligent OCR activities, you can process documents using APIs, by following four main phases: digitization, classification, extraction, and validation.

Similarly to processing documents using Document Understanding or Intelligent OCR activities, you can process documents using APIs, by following four main phases: digitization, classification, extraction, and validation.

When you want to use APIs to create document understanding automations, use the following steps:

1. Digitize documents. Visit the [Digitization APIs](https://docs.uipath.com/document-understanding/automation-suite/2024.10/api-guide/use-the-digitization-service) to check the APIs available for digitizing.
2. Classify documents. Visit the [Classification Service](https://docs.uipath.com/document-understanding/automation-cloud/latest/api-guide/use-the-classification-service) to learn how to use the classification service.
3. Validate the classification results. Visit [Validation of a Classification Result](https://docs.uipath.com/document-understanding/automation-cloud/latest/api-guide/validate-a-classification-action) for more information.
4. Extract documents using the [Extraction Service](https://docs.uipath.com/document-understanding/automation-cloud/latest/api-guide/use-the-extraction-service). Visit the Extraction Service to learn how to use the extraction service.
5. Validate the extraction information. Visit [Validation of an Extraction Result](https://docs.uipath.com/document-understanding/automation-cloud/latest/api-guide/validate-an-extraction-action) to learn how to validate parts of the documents you extracted.

## Known limitations

We are aware of the following limitations that Document Understanding<sup>TM</sup> API calls have:

* They require programming experience.
* They don't provide access to other platform capabilities.