Multipeer Connectivity

The Multipeer Connectivity APIs, introduced in iOS 7, therefore may well be the most significant for the platform. It allows developers to completely reimagine how mobile apps are built, and to redefine what is possible. And we’re not just talking about successors to the lame bump-to-send-contact-information genre, either: multi-peer connectivity has implications on everything from collaborative editing and file sharing to multiplayer gaming and sensor aggregation.

→ nshipster.com/multipeer-connectivity/

Multipeer Connectivity (introduced in iOS 7) lets nearby iPhones, iPads, and Macs talk directly to each other using Wi-Fi, peer-to-peer Wi-Fi, or Bluetooth. No internet, no server, no central service required.

Key ideas:

• Devices advertise themselves with a short service type (e.g., “myapp-game”).
• Other devices browse for that service and ask to connect.
• Once connected, they form an MCSession and can exchange three kinds of data:
  • Messages (small chunks, reliable or best-effort)
  • Streams (continuous data such as audio or video)
  • Resources (whole files, with built-in progress tracking)

Apple even gives MCBrowserViewController, a ready-made screen that handles discovery and invitation for you.

Advantages:

• Works completely offline
• Fully encrypted when you want it
• No API keys, no rate limits, no cloud costs
• Automatic handling of NAT traversal and connection types

Common uses today:

• Multiplayer games
• Real-time collaboration (drawing, notes, whiteboard)
• AirDrop-style file sharing
• Mesh chat or walkie-talkie apps
• Sharing sensor data between devices

It remains one of the most powerful and under used frameworks on Apple platforms. If your app involves several nearby people or devices, Multipeer Connectivity is usually the simplest and most private way to make them talk.