Connecting to a Network

After installing Polkadart and generating types, you’re ready to connect to a network and start querying the blockchain.

Setting Up Your Connection

Using Provider with Generated APIs

Create a new file bin/demo.dart and add the following code:

import 'package:demo/generated/polkadot/polkadot.dart';
import 'package:polkadart/provider.dart';

Future<void> main(List<String> arguments) async {
  final provider = Provider.fromUri(Uri.parse('wss://rpc.polkadot.io'));
  final polkadot = Polkadot(provider);

  final query = await polkadot.rpc.state.getRuntimeVersion();
  print(query.toJson());
}

Running Your Application

Execute your application with:

dart run bin/demo.dart

Expected Output

You should see the runtime version of the Polkadot chain:

{
  specName: polkadot,
  implName: parity-polkadot,
  authoringVersion: 0,
  specVersion: 1003003,
  implVersion: 0,
  apis: [...],
  transactionVersion: 26,
  stateVersion: 1
}

🎉 Success! You’ve successfully connected to Polkadot and made your first query to the chain!

Connecting to Different Networks

final provider = Provider.fromUri(Uri.parse('wss://rpc.polkadot.io'));

final provider = Provider.fromUri(Uri.parse('wss://kusama-rpc.polkadot.io'));

final provider = Provider.fromUri(Uri.parse('wss://westend-rpc.polkadot.io'));

final provider = Provider.fromUri(Uri.parse('ws://127.0.0.1:9944'));

Connection Options

You can customize your connection with additional options:

final provider = Provider.fromUri(
  Uri.parse('wss://rpc.polkadot.io'),
  // Add connection options here if needed
);