The main function of a reverse proxy in web development is to act as an intermediary between clients and servers, offering benefits such as improved security, load balancing, and caching. By receiving client requests and forwarding them to the appropriate server, reverse proxies can hide the server's identity and protect it from direct exposure to the internet. This setup enhances security by filtering malicious traffic and can also improve performance by distributing workloads across multiple servers, allowing for efficient resource utilization and faster response times.