This project is a multithreaded C++ integration library that provides several numerical methods for calculating definite integrals, including Trapezoidal Rule, Simpson's Rule, Monte Carlo Integration, and Adaptive Quadrature. It is designed to handle large computations efficiently by leveraging concurrency and supports both default and user-defined functions for integration. The library is integrated with Python using Pybind11, allowing seamless access to its features from Python scripts. Additionally, FastAPI endpoints are provided to expose the integration methods via a REST API, enabling external applications to make integration requests and receive results in JSON format. This project is modular and extensible, making it easy to add more methods and extend its functionality.