Asos launched its Marketplace website on Tuesday, and said the venture has little in common with similar offerings such as eBay’s.

The site, which enables designers, brands, individuals and independent retailers to sell clothing and accessories, launched with 21 boutiques but Asos ecommerce director James Hart said it “wasn’t a numbers game”.

Hart said: “We want to put the world’s best fashion in front of our customers. There is some good stuff on eBay and some not so good stuff - the customer really has to work to find the prize items.”

Asos has only accepted 5% of the boutique applications it has received so far. Many were rejected either for style reasons or because of customer service concerns, to ensure the Asos brand is protected. The approach will be watched keenly by other retailers running or intending to launch marketplaces.

Hart said Asos received hundreds of boutique applications a week but was determined to control quality.

“Sellers need to be able to run a credible store,” he said. “It needs to have a range rather than just four items and it needs to deliver customer service. This means responding to customers quickly and supplying packaging with goods.”

Further vetting will take place when stores are operational. Mystery shoppers will be deployed and Asos will use customer feedback to identify struggling stores.

Marketplace will drive revenue through commission payments and charging rent on boutiques. Boutique owners pay £50 per month and a 15% commission from sales.

Asos is among a growing number of retailers that have launched marketplaces. It will also launch its Fashion Finder initiative as a beta site before the end of the year.