What We're Building

Our API takes invoice images as input and returns structured JSON data containing:

How To Create Your Gemini API Key:

Please visit Google AI Studio Or Google Vertex and create your Gemini API Key and copy it which will be required to use gemini-2.5-pro model.

Create a .env file in your project directory and Paste The Gemini API key just like below

Let's dive into the code!

Project Structure

Create a requirements.txt file in your project directory

Create a main.py file in your project directory

Code Breakdown

1. Imports and Setup

What's happening here:

2. Application Configuration

Key features:

3. Gemini AI Configuration

Security note: Always store API keys in environment variables, never in code!

4. Image Validation and Optimization

Why optimization matters:

5. The Core OCR Function

We Will Define The Prompt for Extracting Invoice Data

Prompt engineering insights:

6. Processing the AI Response

Response handling:

7. Main API Endpoint

Security and validation:

8. Utility Endpoints

Why these matter:

Running the API

Example Response

Why This Approach Works

This API demonstrates how modern AI models can transform traditional OCR tasks into intelligent document processing systems. The combination of FastAPI's performance and Gemini's intelligence creates a powerful tool for automating invoice processing workflows.

Here is The Complete Code of main.py