Zalando has raised its profit outlook to the upper half, after hailing its “strongest-ever second-quarter active customer growth” and fastest site growth since 2013.

The Germany-based fashion retailer said its adjusted group profits for the second quarter grew 6.4% to €101.7m, while total sales swelled by 20.1% to more than €1.5bn for the period.

The etailer also said it added more than 3.7 million new customers to its ecommerce platform, a 15.2% increase year on year, which brought the total number of users to 28.3 million across Zalando’s 17 European markets.

Visits to the etailer’s site grew 34.3% to over 986 million, 84% of which were through mobile devices.

As a result, the etailer raised its profit outlook to the upper half of the €175m to €225m adjusted profit range.

The retailer also increased its network of bricks-and-mortar stores connected to its platform to more than 1,300.

Zalando boss David Schröder hailed progress in the second quarter and said more customers than ever were choosing the marketplace “as their starting point for fashion”.

“More customers than ever before have chosen Zalando as their starting point for fashion. This proves that our continuous efforts to deliver a best-in-class fashion experience pay off.

“Our platform transition continues to accelerate. The growth of our partner programme leads to a more attractive and diverse assortment for our customers. We will continue to see GMV growing faster than revenues, fully in line with our long-term strategy.”