When launching a marketplace, there are two solutions for a platform software:
Development of software from scratch, the so-called custom development
Introduction of a modular type
Your choice depends on a particular business and its tasks. The essential part is to have a competitive idea and good suppliers. For something breakthrough, a custom marketplace will do. Your next step is to stick to a wise marketing strategy and promote properly.
If you want to establish a trading platform, attract sellers, and receive interests from sales, then it is more beneficial to proceed with ready-made software for a multi-vendor marketplace, like this Merkeleon app. Plus, this model is great for a business that only takes its first steps on the market.