Building a Multimodal AI Chatbot with Flask, Transformers, and BLIP

Introduction
In today’s rapidly evolving AI landscape, combining multiple modalities—such as text and images—into a single system offers more intuitive and dynamic user interactions. This article guides you through the process of building a lightweight multimodal chatbot using Flask, Hugging Face Transformers, and BLIP (Bootstrapped Language Image Pretraining).
You can find the complete project here:
👉 GitHub: multimodal-chatbot-app
💡 What is a Multimodal Chatbot?
Unlike traditional chatbots that only handle text, multimodal chatbots process multiple forms of input, such as:
🧾 Natural language queries (text)
🖼️ Image uploads for captioning
This makes the interaction more versatile—for example, a user can ask a science question or upload an image and get a description of what it contains.
🧰 Tech Stack
Here’s a breakdown of the tools and frameworks used:
Feature | Tool/Library |
Backend Server | Flask |
Language Model | Hugging Face Transformers |
Image Captioning | Salesforce BLIP (via Transformers) |
ML Framework | PyTorch |
Image Handling | Pillow (PIL) |
🚀 How It Works
1. Text-Based Q&A
For science-related questions, the chatbot uses a pre-trained DistilBERT model fine-tuned on the SQuAD dataset to generate answers.
Example:
Q: What is the boiling point of water?
A: The boiling point of water is 100°C.
2. Image Captioning
When a user uploads an image, the app uses BLIP (by Salesforce) to generate a human-like description of the image.
Example:
📷 Image: A cat on a bench
🧠 Output: “A cat sitting on a wooden bench outdoors.”
🧪 Installation Guide
⚙️ I recommend using a virtual environment to avoid dependency conflicts.
- Clone the repo:
git clone https://github.com/EkeminiThompson/multimodal-chatbot-app.git
cd multimodal-chatbot-app
- Set up environment:
python3 -m venv venv
source venv/bin/activate # macOS/Linux
# .\venv\Scripts\activate # Windows
- Install dependencies:
pip install -r requirements.txt
- Run the app:
python multimodal_chatbot.py
Open your browser or Postman and access:
🔗 http://127.0.0.1:5000/chat
🧠 Code Overview
The core logic lives in multimodal_chatbot.py
. The /chat
endpoint handles both text and image POST requests:
@app.route('/chat', methods=['POST'])
def chat():
if 'text' in data:
# handle Q&A
elif 'image' in request.files:
# handle image captioning
Both models are loaded during startup using Hugging Face's pipeline()
function.
🧪 Testing the Endpoints
🧾 For Text
curl -X POST http://127.0.0.1:5000/chat \
-H "Content-Type: application/json" \
-d '{"text": "What is the chemical formula of water?"}'
🖼️ For Image
Use Postman or any frontend tool to send an image as form data (multipart/form-data
) with the key image
.
🔄 Future Enhancements
Here are some features I’m exploring for future iterations:
🎨 Frontend interface (React, Streamlit, or simple HTML)
🗣️ Voice input using SpeechRecognition
🌐 Deploy to Hugging Face Spaces or Render
🌍 Support for multilingual interaction
📘 Final Thoughts
This project is a great way to experiment with combining multiple AI models to build intelligent systems. Whether you're a developer, researcher, or AI enthusiast, creating a multimodal chatbot offers both a technical challenge and a glimpse into the future of human-computer interaction.
Check out the full code and try it yourself 👉 GitHub Repo
📬 Stay Connected
Let’s connect on:
GitHub: @EkeminiThompson
LinkedIn: linkedin.com/in/ekemini-thompson
If you found this helpful, don’t forget to ⭐️ the repo and share the article!
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Written by

Ekemini Thompson
Ekemini Thompson
Ekemini Thompson is a Machine Learning Engineer and Data Scientist, specializing in AI solutions, predictive analytics, and healthcare innovations, with a passion for leveraging technology to solve real-world problems.