solana_kit_sysvars

System variable (sysvar) account access for the Solana Kit Dart SDK -- provides typed access to Solana runtime sysvar accounts like Clock, Rent, EpochSchedule, and more.

This is the Dart port of @solana/sysvars from the Solana TypeScript SDK.

Installation

Add solana_kit_sysvars to your pubspec.yaml:

dependencies:
  solana_kit_sysvars:

Or, if you are using the umbrella package:

dependencies:
  solana_kit:

Documentation

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

Usage

Sysvar addresses

All Solana sysvar account addresses are available as const Address values.

import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

void main() {
  print(sysvarClockAddress);
  // Address('SysvarC1ock11111111111111111111111111111111')

  print(sysvarRentAddress);
  // Address('SysvarRent111111111111111111111111111111111')

  print(sysvarEpochScheduleAddress);
  // Address('SysvarEpochSchedu1e111111111111111111111111')

  print(sysvarSlotHashesAddress);
  // Address('SysvarS1otHashes111111111111111111111111111')

  print(sysvarSlotHistoryAddress);
  // Address('SysvarS1otHistory11111111111111111111111111')

  print(sysvarStakeHistoryAddress);
  // Address('SysvarStakeHistory1111111111111111111111111')

  print(sysvarRecentBlockhashesAddress);
  // Address('SysvarRecentB1ockHashes11111111111111111111')

  print(sysvarInstructionsAddress);
  // Address('Sysvar1nstructions1111111111111111111111111')

  print(sysvarEpochRewardsAddress);
  // Address('SysvarEpochRewards1111111111111111111111111')

  print(sysvarLastRestartSlotAddress);
  // Address('SysvarLastRestartS1ot1111111111111111111111')
}

Fetching the Clock sysvar

The Clock sysvar contains data about the current slot, epoch, and Unix timestamp. It is updated every slot.

import 'package:solana_kit_rpc/solana_kit_rpc.dart';
import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

Future<void> main() async {
  final rpc = createSolanaRpc('https://api.devnet.solana.com');

  final clock = await fetchSysvarClock(rpc);
  print('Current slot: ${clock.slot}');
  print('Current epoch: ${clock.epoch}');
  print('Unix timestamp: ${clock.unixTimestamp}');
  print('Epoch start timestamp: ${clock.epochStartTimestamp}');
  print('Leader schedule epoch: ${clock.leaderScheduleEpoch}');
}

The SysvarClock class contains:

import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

void main() {
  // Construct a SysvarClock value directly (e.g. for testing).
  final clock = SysvarClock(
    slot: BigInt.from(100),
    epochStartTimestamp: BigInt.from(1700000000),
    epoch: BigInt.from(5),
    leaderScheduleEpoch: BigInt.from(6),
    unixTimestamp: BigInt.from(1700001000),
  );

  print(clock.slot); // 100
  print(clock.epoch); // 5
}

Fetching the Rent sysvar

The Rent sysvar contains rent configuration for the cluster.

import 'package:solana_kit_rpc/solana_kit_rpc.dart';
import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

Future<void> main() async {
  final rpc = createSolanaRpc('https://api.devnet.solana.com');

  final rent = await fetchSysvarRent(rpc);
  print('Lamports per byte-year: ${rent.lamportsPerByteYear}');
  print('Exemption threshold: ${rent.exemptionThreshold} years');
  print('Burn percent: ${rent.burnPercent}%');
}

Fetching the EpochSchedule sysvar

The EpochSchedule sysvar includes the number of slots per epoch, leader schedule timing, and warmup information.

import 'package:solana_kit_rpc/solana_kit_rpc.dart';
import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

Future<void> main() async {
  final rpc = createSolanaRpc('https://api.devnet.solana.com');

  final schedule = await fetchSysvarEpochSchedule(rpc);
  print('Slots per epoch: ${schedule.slotsPerEpoch}');
  print('Leader schedule slot offset: ${schedule.leaderScheduleSlotOffset}');
  print('Warmup: ${schedule.warmup}');
  print('First normal epoch: ${schedule.firstNormalEpoch}');
  print('First normal slot: ${schedule.firstNormalSlot}');
}

Fetching encoded sysvar accounts

For sysvars that do not yet have a dedicated fetch function, or when you need the raw encoded bytes, use fetchEncodedSysvarAccount.

import 'dart:typed_data';

import 'package:solana_kit_accounts/solana_kit_accounts.dart';
import 'package:solana_kit_rpc/solana_kit_rpc.dart';
import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

Future<void> main() async {
  final rpc = createSolanaRpc('https://api.devnet.solana.com');

  // Fetch the raw encoded data for any sysvar.
  final maybeAccount = await fetchEncodedSysvarAccount(
    rpc,
    sysvarSlotHashesAddress,
  );

  switch (maybeAccount) {
    case ExistingAccount<Uint8List>(:final account):
      print('SlotHashes data: ${account.data.length} bytes');
    case NonExistingAccount():
      print('Sysvar account not found');
  }
}

Using sysvar codecs

Each sysvar type has encoder, decoder, and codec factory functions for binary serialization.

import 'dart:typed_data';

import 'package:solana_kit_sysvars/solana_kit_sysvars.dart';

void main() {
  // Encode a Clock sysvar value to bytes.
  final encoder = getSysvarClockEncoder();
  final clock = SysvarClock(
    slot: BigInt.from(42),
    epochStartTimestamp: BigInt.from(1700000000),
    epoch: BigInt.from(5),
    leaderScheduleEpoch: BigInt.from(6),
    unixTimestamp: BigInt.from(1700001000),
  );
  final bytes = encoder.encode(clock);
  print(bytes.length); // 40 (sysvarClockSize)

  // Decode bytes back to a SysvarClock.
  final decoder = getSysvarClockDecoder();
  final (decoded, _) = decoder.read(bytes, 0);
  print(decoded.slot); // 42

  // Use the combined codec.
  final codec = getSysvarClockCodec();
  final roundTripped = codec.decode(codec.encode(clock));
  print(roundTripped == clock); // true
}

API Reference

Sysvar addresses

Constant	Address
`sysvarClockAddress`	`SysvarC1ock11111111111111111111111111111111`
`sysvarRentAddress`	`SysvarRent111111111111111111111111111111111`
`sysvarEpochScheduleAddress`	`SysvarEpochSchedu1e111111111111111111111111`
`sysvarEpochRewardsAddress`	`SysvarEpochRewards1111111111111111111111111`
`sysvarInstructionsAddress`	`Sysvar1nstructions1111111111111111111111111`
`sysvarLastRestartSlotAddress`	`SysvarLastRestartS1ot1111111111111111111111`
`sysvarRecentBlockhashesAddress`	`SysvarRecentB1ockHashes11111111111111111111`
`sysvarSlotHashesAddress`	`SysvarS1otHashes111111111111111111111111111`
`sysvarSlotHistoryAddress`	`SysvarS1otHistory11111111111111111111111111`
`sysvarStakeHistoryAddress`	`SysvarStakeHistory1111111111111111111111111`

Sysvar types

Class	Fields
`SysvarClock`	`slot`, `epochStartTimestamp`, `epoch`, `leaderScheduleEpoch`, `unixTimestamp`
`SysvarRent`	`lamportsPerByteYear`, `exemptionThreshold`, `burnPercent`
`SysvarEpochSchedule`	`slotsPerEpoch`, `leaderScheduleSlotOffset`, `warmup`, `firstNormalEpoch`, `firstNormalSlot`

Fetch functions

Function	Description
`fetchSysvarClock(rpc, {config?})`	Fetches and decodes the Clock sysvar. Returns `Future<SysvarClock>`.
`fetchSysvarRent(rpc, {config?})`	Fetches and decodes the Rent sysvar. Returns `Future<SysvarRent>`.
`fetchSysvarEpochSchedule(rpc, {config?})`	Fetches and decodes the EpochSchedule sysvar. Returns `Future<SysvarEpochSchedule>`.
`fetchEncodedSysvarAccount(rpc, address, {config?})`	Fetches any sysvar as a `MaybeEncodedAccount`.

Codec functions

Sysvar	Encoder	Decoder	Codec
Clock	`getSysvarClockEncoder()`	`getSysvarClockDecoder()`	`getSysvarClockCodec()`
Rent	`getSysvarRentEncoder()`	`getSysvarRentDecoder()`	`getSysvarRentCodec()`
EpochSchedule	`getSysvarEpochScheduleEncoder()`	`getSysvarEpochScheduleDecoder()`	`getSysvarEpochScheduleCodec()`

Size constants

Constant	Value	Description
`sysvarClockSize`	`40`	Size of the Clock sysvar data in bytes.
`sysvarRentSize`	`17`	Size of the Rent sysvar data in bytes.
`sysvarEpochScheduleSize`	`33`	Size of the EpochSchedule sysvar data in bytes.

Example

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

Import path: package:solana_kit_sysvars/solana_kit_sysvars.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.

solana_kit_sysvars

Installation

Documentation

Usage

Sysvar addresses

Fetching the Clock sysvar

Fetching the Rent sysvar

Fetching the EpochSchedule sysvar

Fetching encoded sysvar accounts

Using sysvar codecs

API Reference

Sysvar addresses

Sysvar types

Fetch functions

Codec functions

Size constants

Example

Maintenance

Libraries

solana_kit_sysvars package