Gunicorn is a Python WSGI HTTP server that serves web applications. It is designed to handle multiple requests simultaneously, making it suitable for production environments. By using a pre-fork worker model, it can spawn multiple worker processes to manage incoming traffic efficiently. Developed to be simple and lightweight, Gunicorn is compatible with various web frameworks, including Flask and Django. It allows developers to easily deploy their applications and scale them as needed, ensuring better performance and reliability in serving web content.