Stripe has raised $80 million in a series c funding round which values the San Francisco-based payments start-up at $1.75 billion.
The latest financing comes from Sequoia Capital, Founders Fund, Khosla Ventures, and Allen & Co, and brings total funding to around $130 million for the firm, which only launched publicly in late 2011.
Founded by 20-something brothers Patrick and John Collison, Stripe provides merchants with an API that they can embed into their Web sites to easily accept credit card payments.
The company already processes billions of dollars a year - taking a 2.9% cut of transactions and 30 cents - for thousands of firms, including Rackspace, Shopify and DailMotion. In the last year it has begun expanding beyond the US, launching in the UK, Ireland and Canada, and running betas in several other European countries.
Last week speculation surfaced that the firm is close to securing a potentially massive deal with Twitter, helping the micro-blogging giant move into the commerce arena.
Stripe's rapid growth has seen it emerge as the principal rival to e-commerce payments giant PayPal. The eBay unit is understood to have considered acquiring its upstart rival before eventually buying the similar Braintree for $800 million.