Mayank Bidawatka, co-founder of the Koo app, has raised $4 million for his new consumer tech venture, Billion Hearts, in a funding round led by Blume Ventures, with participation from General Catalyst and Athera Venture Partners. An earlier $250K pre-seed round was backed by founders of redBus, Ola, and Myntra. The funds will support building a small, tech-focused global team and launching a beta product early next year on Android and iOS. Koo shut down in July 2024 due to lack of traction and failed M&A attempts.