Introduction

    Welcome to the Expo Document Scanner documentation!

    expo-document-scanner is a high-performance native document scanner for React Native and Expo applications. It leverages native scanning capabilities provided by the OS:

    • iOS: Uses VisionKit for native UI and fast edge detection.
    • Android: Uses ML Kit Document Scanner API for robust, reliable scanning on Android devices.

    Why Expo Document Scanner?

    Many document scanning libraries rely on older bridge-based architectures or require ejecting from Expo. This library is built differently:

    • Built with Nitro Modules: Uses react-native-nitro-modules for lightning-fast, zero-overhead JSI communication between JavaScript and native code.
    • Expo Compatible: Works seamlessly with the Expo managed workflow.
    • Native UIs: Provides a premium scanning experience by using the official native document scanning components provided by Apple and Google.
    • High Quality: Automatically handles perspective correction, cropping, and color enhancement.

    Benefits of Nitro Modules

    By utilizing React Native Nitro Modules, this library achieves performance that traditional React Native bridges cannot match:

    • Zero Bridge Overhead: Calls between JS and native code happen synchronously, avoiding the asynchronous bridge queue.
    • Direct Memory Access: Native objects and arrays are shared directly with JavaScript without expensive serialization/deserialization.
    • Type Safety: Strongly typed interfaces via Swift and Kotlin provide robust guarantees and a smooth developer experience.
    • C++ Core: Under the hood, the module uses C++ to ensure maximum speed and minimal latency when passing large image paths or base64 strings back to JS.

    Explore the Installation guide to get started!