Design a marketplace where freelancers bid on contract jobs with the lowest bid winning the contract.

To design a freelance marketplace where the lowest bid wins, I would focus on a robust architecture that supports user management (freelancers and clients), job posting and searching, a bidding system, and secure payment processing. Key components would include a frontend for user interaction, a backend API to handle business logic and data operations, and a database to store job details, user profiles, bids, and transaction history. The bidding mechanism would need to ensure fairness and transparency, potentially with features like bid deadlines and client review of bids. Scalability and security would be paramount to handle a growing user base and protect sensitive financial information.