Sept 21 (Reuters) - Mirakl said on Tuesday it had raised $555 million in a funding round that valued the tech startup that helps companies set up online marketplaces at more than $3.5 billion. Paris and Boston-based Mirakl said that more than 300 companies already use its platform and the funding, led by private equity firm Silver Lake, will be used to expand its engineer base, customer support, third-party seller ecosystem, as well as increasing its global footprint. “Our vision at the beginning was to enable companies to compete against Amazon because we were destroyed by seeing fantastic businesses stand still, watching digital giants come in and play with different rules,” Adrien Nussenbaum, Mirakl’s co-CEO and co-founder, said in a statement. Mirakl’s software platform allows companies to sell not just their own brands, but curate and sell others by linking them up, Nussenbaum said, adding that it plugs into most e-commerce platforms like Shopify, commonly used to set up online stores. That can help drive more sales through the store, he said, adding that the platform can also be used for wholesale stores. “Airbus ... has created a marketplace to bring together all the vendors of spare parts and maintenance and maintenance products for their clients,” Nussenbaum said with reference to the European aerospace company. (Reporting by Jane Lanhee Lee; Editing by Alexander Smith)