TL;DR. River AI raised .1 billion in funding, led by General Catalyst and AMP PBC, to build an open alternative to proprietary AI platforms. - This capital infusion aims to foster a more accessible and modular AI ecosystem for developers and enterprises. - The 'open AI stack' initiative seeks to challenge the dominance of closed-source foundational models and platforms. - The funding round signals significant investor confidence in open-source AI development and its future growth.