Use when implementing Network.framework connections (NWConnection, NetworkConnection), debugging connection failures, migrating from sockets/URLSession streams, or handling network transitions...
SKILL.md
Swift Networking
Network.framework is Apple's modern networking API for TCP/UDP connections, replacing BSD sockets with smart connection establishment, user-space networking, and seamless mobility handling.
Ignoring state handlers — Creating an NWConnection without a state change handler means you never learn when it's ready or failed. Always implement the state handler first.
Blocking the main thread — Never call receive() on the main queue. Use a background DispatchQueue or Task for all network operations.
Wrong queue selection — Using the wrong queue (UI queue for network work, or serial queue for concurrent reads) causes deadlocks or silent failures. Always explicit your queue choice.
Not handling network transitions — WiFi/cellular switches or network loss aren't always detected automatically. Implement viability checks and state monitoring for robust apps.
Improper error recovery — Network errors need retry logic with backoff. Immediately failing on transient errors (timeouts, temporary loss) creates poor UX.
