📸 FastAPI Instagram API

An Instagram-style REST API built with FastAPI, SQLAlchemy, and SQLite.

This project provides user authentication, posts, comments, image uploads, JWT-based authorization, and relational database management.

✨ Features

• 🔐 User registration and JWT authentication
• 🔑 Password hashing with pwdlib
• 👤 User management
• 📝 Create and delete posts
• 💬 Create, retrieve, and delete comments
• 🖼️ Image/file uploads
• 📁 Static file serving
• 🛡️ Protected endpoints using OAuth2 Bearer tokens
• 🗄️ SQLAlchemy ORM
• 🔗 User, post, and comment relationships
• 📦 Pydantic request and response schemas
• 💾 SQLite database

🛠️ Tech Stack

• Python 3
• FastAPI
• SQLAlchemy
• SQLite
• Pydantic
• JWT
• OAuth2
• pwdlib
• Uvicorn

🏗️ Project Structure

fastapi-instagram-api/
│
├── auth/
│   ├── authentication.py
│   └── oauth2.py
│
├── db/
│   ├── database.py
│   ├── models.py
│   ├── db_user.py
│   ├── db_post.py
│   ├── db_comment.py
│   └── hash.py
│
├── routers/
│   ├── user.py
│   ├── post.py
│   └── comment.py
│
├── uploaded_file/
│
├── main.py
├── schemas.py
├── requirements.txt
├── .gitignore
└── README.md

🔐 Authentication

The API uses OAuth2 Bearer authentication with JWT access tokens.

The authentication flow is:

User Login
    ↓
Validate Credentials
    ↓
Generate JWT
    ↓
Client Sends Bearer Token
    ↓
Validate JWT
    ↓
Get Current User
    ↓
Access Protected Endpoint

Passwords are hashed before being stored in the database.

🗄️ Database Relationships

The project uses SQLAlchemy ORM to model the relationships between users, posts, and comments.

User
 │
 ├── 1 ──── N ──── Post
 │                  │
 │                  └── 1 ──── N ──── Comment
 │
 └── 1 ──── N ──── Comment

Models

User

• id
• username
• email
• password

Post

• id
• image_url
• image_url_type
• caption
• timestamp
• user_id

Comment

• id
• text
• timestamp
• user_id
• post_id

🚀 Getting Started

1. Clone the repository

git clone https://github.com/ARK13-org/fastapi-instagram-api.git
cd fastapi-instagram-api

2. Create a virtual environment

python -m venv .venv

Activate it on Windows:

.venv\Scripts\Activate.ps1

3. Install dependencies

pip install -r requirements.txt

4. Start the application

uvicorn main:app --reload

The API will be available at:

http://127.0.0.1:8000

Interactive API documentation:

http://127.0.0.1:8000/docs

📡 Main Endpoints

Users

POST /user

Create a new user.

Authentication

POST /token

Authenticate a user and receive a JWT access token.

Posts

POST /post/create_post
GET  /post/
POST /post/delete/{id}
POST /post/upload_file

Comments

POST /comment/create_comment
GET  /comment/{id}
POST /comment/delete/{id}

🖼️ File Uploads

The API supports uploading image files.

Uploaded files are stored in the:

uploaded_file/

directory and exposed through FastAPI's static file handling.

🧠 What I Explored

This project helped me practice:

• Building REST APIs with FastAPI
• Dependency injection with Depends
• OAuth2 Bearer authentication
• JWT access tokens
• Password hashing and verification
• SQLAlchemy ORM
• Foreign keys and relationships
• Pydantic schemas
• CRUD operations
• File uploads with UploadFile
• Static file serving
• API response models
• Organizing a FastAPI project into routers, database logic, authentication, and schemas

🔮 Future Improvements

• PostgreSQL support
• Alembic database migrations
• Refresh tokens
• Better authentication and authorization
• User profile endpoints
• Like and follow functionality
• Pagination
• Search and filtering
• Image validation and processing
• Automated tests with Pytest
• Docker support
• Environment-based configuration
• Improved error handling

📚 Project Purpose

This project was built as a practical backend project to learn how different FastAPI components work together in a real-world style application.

It focuses on API design, authentication, database relationships, and backend architecture rather than reproducing the complete Instagram platform.