AI-Powered Receipt Scanning: OCR with Tesseract and React Native

Manual expense entry is tedious. We built an app that photographs receipts and extracts merchant, date, items, and totals automatically.

1. Camera Capture Pipeline

Using Expo Camera, users snap a receipt photo which is cropped and enhanced before OCR:

typescript
import * as ImageManipulator from 'expo-image-manipulator';

const enhanced = await ImageManipulator.manipulateAsync(uri, [
  { resize: { width: 1200 } }
], { compress: 0.8, format: ImageManipulator.SaveFormat.JPEG });

2. Dual OCR Strategy

We first run Tesseract locally for speed. If confidence is below 80%, we fall back to OpenAI Vision API for complex receipts with unusual fonts or handwriting.

3. Structured Data Extraction

The raw OCR text is parsed by a GPT-4 prompt that returns structured JSON with merchant name, date, line items, tax, and total — ready for database storage.

Summary

Combining local OCR with cloud AI fallback gives users instant results while maintaining accuracy above 95% across receipt formats.