Affirm, a three-year-old online lender that finances consumer purchases at the point of sale, has raised a $100 million in equity funding to help it boost distribution and develop new products and services.

Founders Fund, a venture capital firm that has invested in such successful startups as Facebook, Airbnb and Spotify, led this latest round of funding, Affirm said Wednesday. It was joined by several existing investors, including Lightspeed Venture Partners, Spark Capital, Khosla Ventures, Andreesen Horowitz and Jefferies.

Founding Fund partner Brian Singerman will join representatives from Lightspeed, Khosla and Spark on Affirm's board.

Affirm has now raised roughly $425 million in debt and equity funding since it was founded in 2013. The San Francisco company said it plans to use its latest influx of capital to add new merchant partners and develop new services beyond point of sale financing.

Affirm, headed by PayPal co-founder Max Levchin, offers loans to consumers who don't have credit scores or choose not to use credit cards and need help financing big-ticket purchases. Borrowers are informed of the cost, including interest, at checkout online or in stores and repay the loans in fixed monthly installments.

The company now has partnerships with roughly 700 merchants that offer Affirm loans as a payment option at checkout, up from about 100 a year ago. Its merchant partners include the online clothing retailers Trades and TheRealReal, the jewelry retailer and Smile Direct Club, a provider of dental services.

Also on Wednesday, Affirm said that Len Eschweiler, a former managing director at Amazon, has joined the company as senior vice president of retail. Eschweiler most recently served as senior vice president of worldwide sales at the e-commerce firm Avangate. He will largely be responsible for developing partnerships with more retailers.