solana_kit_rpc_subscriptions #

Subscription client for the Solana Kit Dart SDK -- the composition layer that ties together WebSocket channels, the subscriptions API, JSON serialization, and error handling.

This is the Dart port of @solana/rpc-subscriptions from the Solana TypeScript SDK.

Installation #

Add solana_kit_rpc_subscriptions to your pubspec.yaml:

dependencies:
  solana_kit_rpc_subscriptions:

Or, if you are using the umbrella package:

dependencies:
  solana_kit:

Documentation #

• Package page: https://pub.dev/packages/solana_kit_rpc_subscriptions
• API reference: https://pub.dev/documentation/solana_kit_rpc_subscriptions/latest/

Usage #

Creating a subscription client #

The primary entry point is createSolanaRpcSubscriptions, which composes a fully-featured subscription client with BigInt-safe JSON serialization, autopinging, channel pooling, and subscription coalescing.

import 'package:solana_kit_rpc_subscriptions/solana_kit_rpc_subscriptions.dart';
import 'package:solana_kit_rpc_subscriptions_channel_websocket/solana_kit_rpc_subscriptions_channel_websocket.dart';

void main() async {
  // Create a subscription client for devnet.
  final subscriptions = createSolanaRpcSubscriptions(
    'wss://api.devnet.solana.com',
  );

  // Subscribe to account notifications.
  final controller = AbortController();
  final pending = subscriptions.request('accountNotifications', [
    '11111111111111111111111111111111',
    {'encoding': 'base64', 'commitment': 'confirmed'},
  ]);

  final stream = await pending.subscribe(
    RpcSubscribeOptions(abortSignal: controller.signal),
  );

  await for (final notification in stream) {
    print('Account changed: $notification');
    // Unsubscribe after the first notification.
    controller.abort();
  }
}

Including unstable subscription methods #

To access unstable subscription methods like blockNotifications, slotsUpdatesNotifications, and voteNotifications, use createSolanaRpcSubscriptionsUnstable:

import 'package:solana_kit_rpc_subscriptions/solana_kit_rpc_subscriptions.dart';
import 'package:solana_kit_rpc_subscriptions_channel_websocket/solana_kit_rpc_subscriptions_channel_websocket.dart';

void main() async {
  final subscriptions = createSolanaRpcSubscriptionsUnstable(
    'wss://api.devnet.solana.com',
  );

  final controller = AbortController();
  final pending = subscriptions.request('slotsUpdatesNotifications');

  final stream = await pending.subscribe(
    RpcSubscribeOptions(abortSignal: controller.signal),
  );

  await for (final notification in stream) {
    print('Slot update: $notification');
    controller.abort();
  }
}

Customizing channel configuration #

The DefaultRpcSubscriptionsChannelConfig class lets you tune connection pooling, autopinging intervals, and send buffer sizes.

import 'package:solana_kit_rpc_subscriptions/solana_kit_rpc_subscriptions.dart';

void main() {
  final subscriptions = createSolanaRpcSubscriptions(
    'wss://api.mainnet-beta.solana.com',
    DefaultRpcSubscriptionsChannelConfig(
      url: 'wss://api.mainnet-beta.solana.com',
      intervalMs: 10000, // Ping every 10 seconds.
      maxSubscriptionsPerChannel: 200, // More subs per channel.
      minChannels: 2, // Start with 2 channels.
      sendBufferHighWatermark: 256 * 1024, // 256KB send buffer.
    ),
  );
}

Building from a custom transport #

When you need full control over the transport layer, use createSolanaRpcSubscriptionsFromTransport:

import 'package:solana_kit_rpc_subscriptions/solana_kit_rpc_subscriptions.dart';

void main() {
  // Create a custom transport with subscription coalescing.
  final transport = createDefaultRpcSubscriptionsTransport(
    DefaultRpcSubscriptionsTransportConfig(
      createChannel: createDefaultSolanaRpcSubscriptionsChannelCreator(
        DefaultRpcSubscriptionsChannelConfig(
          url: 'wss://api.devnet.solana.com',
        ),
      ),
    ),
  );

  final subscriptions = createSolanaRpcSubscriptionsFromTransport(transport);
}

Subscription coalescing #

When multiple callers subscribe to the same notification with the same parameters, the coalescer deduplicates them into a single server-side subscription. This happens automatically with createSolanaRpcSubscriptions.

import 'package:solana_kit_rpc_subscriptions/solana_kit_rpc_subscriptions.dart';
import 'package:solana_kit_rpc_subscriptions_channel_websocket/solana_kit_rpc_subscriptions_channel_websocket.dart';

void main() async {
  final subscriptions = createSolanaRpcSubscriptions(
    'wss://api.devnet.solana.com',
  );

  // Both subscriptions share a single server-side subscription
  // because they have the same method and params.
  final controller1 = AbortController();
  final pending1 = subscriptions.request('slotNotifications');
  final stream1 = await pending1.subscribe(
    RpcSubscribeOptions(abortSignal: controller1.signal),
  );

  final controller2 = AbortController();
  final pending2 = subscriptions.request('slotNotifications');
  final stream2 = await pending2.subscribe(
    RpcSubscribeOptions(abortSignal: controller2.signal),
  );

  // Both streams receive the same notifications.
  stream1.listen((n) => print('Listener 1: $n'));
  stream2.listen((n) => print('Listener 2: $n'));
}

API Reference #

Factory functions #

Channel creators #

Classes #

Type aliases #

Example #

Use example/main.dart as a runnable starting point for solana_kit_rpc_subscriptions.

• Import path: package:solana_kit_rpc_subscriptions/solana_kit_rpc_subscriptions.dart
• This section is centrally maintained with mdt to keep package guidance aligned.
• After updating shared docs templates, run docs:update from the repo root.

Maintenance #

• Validate docs in CI and locally with docs:check.
• Keep examples focused on one workflow and reference package README sections for deeper API details.