Stackup

Stackup is a suite of open-source developer tools for building user-friendly blockchain products. It starts with ERC-4337 infrastructure.

Winter offers an embeddable checkout widget for businesses & NFT projects to sell NFTs through a credit card

Y Combinator

Listia is a new kind of auction marketplace for giving and getting free stuff.

Y Combinator

[Inactive] Tinker is a cryptocurrency electronic trading & market making firm

Y Combinator