Building Actual Peer-to-peer Applications: Outside Misconceptions

Peer-to-peer (P2P) applications are often misunderstood as insecure, illegal file-sharing networks that operate without any servers. In reality, P2P systems are decentralized architectures where each participant acts as both client and server, enabling direct resource sharing without central control. Building production P2P applications requires addressing three critical layers: Network (using libraries like libp2p for peer discovery and DHT-based routing), Data (implementing CRDTs for conflict-free eventual consistency), and Security (employing ECDSA cryptographic signatures for authentication and integrity). Modern P2P systems typically use bootstrap nodes for initial discovery, support NAT traversal, and combine structured overlays like Kademlia DHT with gossip protocols for resilience. The article demonstrates these concepts through a practical expense tracker application that showcases how proper P2P architecture achieves scalability, censorship resistance, and distributed resource utilization while maintaining security and data consistency.