MARTI (Multi-Agent Reinforcement learning Toolkit and Interface) is a research-oriented framework that streamlines the development, evaluation, and benchmarking of multi-agent RL algorithms. It offers a plug-and-play architecture where users can configure custom environments, agent policies, reward structures, and communication protocols. MARTI integrates with popular deep learning libraries, supports GPU acceleration and distributed training, and generates detailed logs and visualizations for performance analysis. The toolkit’s modular design allows rapid prototyping of novel approaches and systematic comparison against standard baselines, making it ideal for academic research and pilot projects in autonomous systems, robotics, game AI, and cooperative multi-agent scenarios.