requests-racer is a Python library designed to facilitate the testing and exploitation of race conditions in web applications. The library builds upon the popular Requests HTTP library to provide specialized functionality for creating concurrent HTTP requests. The tool enables security researchers and penetration testers to send multiple HTTP requests simultaneously or in rapid succession to identify timing-based vulnerabilities. Race conditions occur when multiple processes or threads access shared resources concurrently, potentially leading to unexpected behavior or security vulnerabilities. The library simplifies the process of crafting and executing race condition attacks by providing an easy-to-use interface for manipulating HTTP requests. Users can configure various parameters such as request timing, concurrency levels, and request variations to test different race condition scenarios. requests-racer is particularly useful for testing web applications that handle concurrent user actions, such as payment processing, account creation, or resource allocation systems where race conditions might lead to security issues like privilege escalation or data corruption.