Layer-2 firm Polygon Labs also participated in the investment round, a spokesperson for Espresso told CoinDesk over email. According to a screenshot tweeted by the Espresso team, other investors included the layer-2 developers StarkWare and Taiko. Offchain Labs, the main developer behind Arbitrum, the biggest layer-2 network, backed Espresso, according to a post on X by CEO Steven Goldfeder.