What are blue and red blocks in Kaspa?

Every block in Kaspa's network is assigned one of two labels through a process called Block Classification. A blue block is consensus-valid — the network has agreed it belongs in the shared transaction history. A red block is potentially conflicting — it could not be accepted without introducing ambiguity into that agreed-upon order. Understanding blue versus red blocks matters for beginners because this classification is how Kaspa decides which blocks actually count toward confirmed transactions.