This repository provides a Python library and CLI tool for optimizing daily fantasy sports (DFS) lineups on DraftKings and FanDuel. It reads player salary and projection data from CSV files, enforces contest-specific constraints (salary cap, position limits, custom rules like stacks and exposure), and uses Google OR-Tools to solve the constrained optimization problem, producing lineups that maximize projected points. The library supports a wide range of sports (NFL, NBA, MLB, NHL, soccer, golf, NASCAR, tennis, CS:GO, F1, XFL, and various Showdown/Pickem contest types) and includes utilities for downloading salary CSVs and generating upload files for mass lineup entry. The architecture is a classic monolithic Python package with a clear separation of concerns: data parsing (`csv_parse/`), player pool construction (`player_pool.py`), constraint definition (`lineup_constraints.py`, `settings.py`), optimization core (`optimizer.py`), and output formatting (`orm.py`, `uploaders.py`). The test suite is comprehensive with sport-specific tests and CSV fixtures. The codebase demonstrates practical application of constraint programming to a real-world combinatorial optimization problem, though some components are tightly coupled to the DFS domain.