If you want to buy Jack Dorsey’s first tweet, you’d better get your bid in. The billionaire co-founder and CEO of Twitter put the tweet up for digital auction as an NFT —non-fungible token— a digital good that lives on the Ethereum blockchain. Dorsey’s 15-year-old tweet is up for sale on a platform called Valuables by Cent that lets people make offers on tweets that are “autographed by their original creators.”

On Sunday afternoon, the high bid for Dorsey’s tweet, the succinct “just setting up my twttr,” was at $2.5 million, from Sina Estavi, CEO of Bridge Oracle.

Obviously you’re not buying the actual tweet, but as Valuables by Cent’s FAQ page explains, you get a digital certificate of the tweet with your purchase, which is “unique because it has been signed and verified by the creator.”

Dorsey tweeted he was ending the NFT auction March 21st (but not what time, pls hurry up Jack, we’re on deadline here), would convert the proceeds to Bitcoin then send to Give Directly for its Africa Response. Give Directly is a charitable organization that, as its name suggests, gives money directly to people living in poverty. So, OK, good job there, Jack.

Tweets are not the only items that can be sold as NFTs; the technology is taking over the art world as well. On March 11th, an NFT of a work by Mike Winkelmann — the digital artist known as Beeple — sold for $69 million at Christie’s, making him “among the top three most valuable living artists,” according to the auction house.

But if you want to own a digital signature (aka an autograph) of the Twitter CEO’s first tweet, the clock is ticking.