What are isolates?

Learn the Dart concurrency model with isolates.

What are isolates?

An isolate is Dart's unit of isolated execution. Each isolate has its own memory, its own event loop and its own stack.

Unlike threads, two isolates do not share memory; this removes the need for locks or mutexes. They communicate only by message passing — through SendPort and ReceivePort.

This design eliminates race conditions up front. Heavy work is moved to the background without blocking the main isolate.

How do you start an isolate?

A new isolate is started with Isolate.spawn(entryPoint, args). entryPoint must be a top-level function (or a static method); it cannot capture closure variables.

Signature: void entryPoint(List<String> args). The args list is passed as the second argument to spawn; typically the first element is a SendPort.

Example: Isolate.spawn(worker, ['gorev-1']);. This schedules the new isolate; the main isolate continues.

Exercise Define the entryPoint function

Define a top-level void entryPoint(List<String> args) function. Its body should do print('Isolate ${args[0]} çalışıyor'). Inside main call this function with the argument ['gorev-1'].

Show example solution

void entryPoint(List<String> args) {
  print('Isolate ${args[0]} çalışıyor');
}

void main() {
  entryPoint(['gorev-1']);
}

Test yourself

Which statement about isolates is true?
- They have their own memory, not shared
- They can only use a single CPU core
- They share memory and need locks
- It means the same thing as a thread
Show answer

They have their own memory, not shared — each isolate owns its memory and does not share it.

Complete the spawn call

Isolate.spawn(
  ____,
  ['gorev-1'],
);

Show answer

Isolate.spawn(
  entryPoint,
  ['gorev-1'],
);

Match the isolate concepts

Isolate

Isolated worker
SendPort

Message sending channel
Memory

Unshared area
Event loop

Event queue

Next lesson: Isolate.spawn

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