The NFT marketplace OpenSea has raised $23 million for its Series A funding round, according to a statement from the startup's CEO.

The round was led by the crypto-friendly VC firm Andreessen Horowitz. Dallas Mavericks owner (and Ethereum enthusiast) Mark Cuban, angel investor Naval Ravikant, and Metapurse—a fund from the pseudonymous NFT investor MetaKovan—have also invested in the company.

The market for NFTs, or non-fungible tokens, has seen massive growth over the past few months. NFTs are most recognizable as digital, blockchain-based collectibles that can take the form of anything online; the recent boom has seen them applied to everything from visual art to music to tweets.

Musicians like Grimes, Kings of Leon, and Yaeji have all gotten involved with NFTs, and the digital artist Beeple just sold an NFT at Christie’s for $69 million.

OpenSea was founded in 2017, as a product of Y Combinator’s startup accelerator program. Last week, it auctioned off a series of NFT trading cards themed after four-time Super Bowl champion Rob Gronkowski, which sold for more than $1.6 million.

OpenSea is one of many online auction houses riding the NFT wave. According to the crypto data company Messari, the Winklevoss twins’ NFT platform, Nifty Gateway, may be worth over $1 billion.