What is the difference between debug, profile, and release build modes in Flutter?

Debug mode uses the Dart JIT compiler, enabling Hot Reload and Hot Restart. It includes assertion checks, widget inspector support, and detailed error messages, but runs significantly slower than release. Profile mode uses AOT compilation like release but retains profiling hooks, allowing DevTools to measure real-world performance without debug overhead — always profile on a real device in this mode. Release mode uses full AOT compilation with all optimizations, tree shaking, and no debugging overhead — this is what ships to users and is dramatically faster than debug.