Campaign Marketplace Website Development

I need a web-based marketplace where campaign creators can publish live campaigns and participants can join, submit their entries, and track their standing on a real-time leaderboard. The scope is mid-level:... (Budget: ₹12500 - ₹37500 INR, Jobs: Backend Development, GraphQL, MySQL, Node.js, NoSQL Couch & Mongo, PHP, PostgreSQL, REST API, Web Development)