In Dart, both var and dynamic are used to declare variables without explicitly specifying a type, but they behave differently in terms of type safety and compile-time checks.
var:
When you declare a variable withvar, Dart infers the type at compile-time based on the initial value. Once inferred, the type is fixed, and you cannot assign a value of a different type later.
var name = 'Aswini'; // inferred as String
// name = 42; // Error: a String variable can't be assigned an int
dynamic:
When you declare a variable with dynamic, Dart allows any type to be assigned at runtime. The type can change over time, and the compiler does not enforce type safety.
dynamic value = 'Hello';
value = 42; // Allowed
value = true; // Also allowed
I’ve applied var and dynamic in Flutter projects while handling API responses. I use var when I know the expected type, which helps catch errors early at compile-time. I use dynamic when dealing with loosely typed JSON or when the type can vary, but I always combine it with runtime checks using is or as to avoid errors.
A challenge I faced was overusing dynamic — it made debugging harder because type-related mistakes only appeared at runtime. A limitation of dynamic is the lack of compile-time type checking, so for safer code, strongly typed variables or model classes are recommended.
In short: var = inferred and fixed type; dynamic = flexible type that can change at runtime.