NFT exchange OpenSea made just $28,000 a month when it launched 4 years ago. Now its founders are about to be crypto billionaires.

• NFT marketplace OpenSea made a meager $28,000 per month in revenue two years ago, Forbes reported.
• Its founders decided it would fold if sales didn't double by the end of 2020 — then hit that goal by September of that year.

After two years in operation, the founders of OpenSea, an exchange for non-fungible tokens, were nearing a make-or-break moment.

By March 2020, the platform was still only making a meager $28,000 in commission revenue per month since launching in December 2017, Forbes reported in a November 23 profile titled "What Every Crypto Buyer Should Know About OpenSea, The King Of The NFT Market."

The founders — 31-year-old Devin Finzer and 29-year-old Alex Atallah — said the market for NFTs felt dead and planned on folding if business hadn't doubled by year-end, according to the article.

By September 2020, they met that goal, Forbes wrote.

The doubling in revenue, which is derived from a 2.5% commission on transactions, was just a precursor of what was to come.

OpenSea, now the largest NFT marketplace by trading volume, jumped from $1.1 million in transactions per month when it was struggling to get started, to an all-time high of $3.4 billion in August 2021 (producing $85 million in commission revenue), Forbes said.

With the explosion of the NFT marketplace, Finzer and Atallah have scored a net worth in the hundreds of millions of dollars, and they're soon to be the newest billionaires in the crypto world, Forbes wrote.

Since its days as a little-known operation, OpenSea has become the go-to marketplace for NFTs, selling collections like CryptoPunks, the Bored Ape Yacht Club, Decentraland, and even a tungsten cube.

NFTs are digital assets like artwork tied to the blockchain. While bitcoin tokens are fungible, or replicable, NFTs derive their value from the fact that they're one-of-a-kind. Some skeptics, however, say there's no value, and they can simply right-click and save the image.

Even so, the marketplace for NFTs has ballooned this year. In the third-quarter alone, NFTs registered $10.7 billion in trading volume – a 704% jump from about $2 billion the previous quarter.

In the interview with Forbes, Finzer said OpenSea succeeded by "being in the right place at the right time."