AltTextAlternative 🖼️ ✍️

AltTextAlternative is a high-efficiency, AI-powered API designed to generate descriptive accessibility alt-text for images. Built with FastAPI and powered by the Salesforce BLIP (Bootstrapping Language-Image Pre-training) model via Hugging Face, it provides a stable, free-forever solution for web accessibility.

🚀 Key Features

• High-Accuracy Descriptions: Uses the blip-image-captioning-large model for human-like captions.
• TIF/TIFF Support: Custom processing pipeline to handle heavy medical and scientific image formats.
• Resource Optimized: Automatic image compression to save bandwidth and stay within API quotas.
• Free Forever: Optimized for the Hugging Face Serverless Inference API (~1,000 requests/day).

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🛠️ Architecture & Components

The system is composed of three main layers to ensure stability and cost-efficiency:

1. FastAPI Backend: Provides the interface for HTTP multipart/form-data requests.
2. Pillow Processing Engine: A middleware layer that converts heavy or unsupported formats (like .tif) into optimized, RGB-encoded JPEGs (resized to 800px).
3. HF Inference Layer: Communicates with Hugging Face's global GPU cluster using a "retry-on-load" strategy to handle model cold starts.

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🚦 Getting Started

1. Prerequisites

• Python 3.9+
• A Hugging Face Access Token. Create one for free at hf.co/settings/tokens (ensure it has Inference permissions).

2. Environment Setup

Set your API key as an environment variable in your hosting platform (Render, Vercel, or locally):

HF_API_KEY=your_huggingface_token_here

🚦 Local Installation

To get the project running on your local machine, follow these steps:

1. Prerequisites

• Python 3.9 or higher installed.
• A Hugging Face Access Token with Inference permissions.

2. Setup Procedure

# Clone your repository
git clone [https://github.com/your-username/alttextalternative.git](https://github.com/your-username/alttextalternative.git)
cd alttextalternative

# Create and activate a virtual environment
python -m venv venv

# On Windows:
venv\Scripts\activate
# On Mac/Linux:
source venv/bin/activate

# Install required libraries
pip install -r requirements.txt

3. Environment Configuration

To keep your API keys secure, use a .env file in the root directory. Never commit your .env file to GitHub.

Create a file named .env:

HF_API_KEY=hf_your_actual_token_here