# Overview

Keyless Mobile Document SDK offers the following APIs:

1. [Read the MRZ](https://github.com/KeylessTech/docs.keyless.io/blob/master/spaces/mobile-document-sdk/introduction/mobile-document-sdk/read-mrz.md)
2. [Read the NFC tag](https://github.com/KeylessTech/docs.keyless.io/blob/master/spaces/mobile-document-sdk/introduction/mobile-document-sdk/read-nfc.md)
3. [Scan Document = Read MRZ + Read NFC](https://github.com/KeylessTech/docs.keyless.io/blob/master/spaces/mobile-document-sdk/introduction/mobile-document-sdk/scan-document.md)

In this section we briefly summarize when to use which API. All details for the specific API can be found in the dedicated section.

## Read MRZ

Reads the Machine Readable Zone - MRZ - data from a document using device camera. Keyless Document SDK performs optical character recognition - OCR - on the MRZ zone of the document. It also offer a fallback form where users can input MRZ data manually in case the OCR fails.

The read MRZ API comes handy if you want to show the data read from the MRZ to the user for validation before proceeding to the NFC scan of the tag in the document.

## Read NFC

Reads the document data stored on the device chip using [Near Field Communication - NFC](https://nfc-forum.org/).

{% hint style="warning" %}
NFC must be enabled on the device to read the document chip data.
{% endhint %}

The read NFC API comes handy if you already have your own OCR system and already retrieved the MRZ data. In such scenario the Keyless Document SDK can be used only to read the data contained in the Document chip.

## Scan Document

Reads the MRZ, computes the key to unlock the document chip and reads the document chip using NFC.\
This is the complete flow to retrieve the document data. The Keyless Document SDK performs the OCR and then prompts the user to hold the device against the document to read its data. At the end of the process the document data is returned as result.

The Scan Document API comes handy if you want the Keyless Document SDK to handle the entire process combining reading the MRZ and reading the NFC tag.


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