Deferred Execution

Every Solana transaction includes a recent blockhash—a reference to a recent network state that proves the transaction was created "now." The network rejects any transaction with a blockhash older than ~150 blocks (~60-90 seconds), preventing replay attacks and stale submissions. This works perfectly for real-time payments. But it breaks workflows that need a gap between signing and submission, such as:

Scenario	Why Standard Transactions Fail
Treasury operations	CFO in Tokyo signs, Controller in NYC approves—90 seconds isn't enough
Compliance workflows	Transactions need legal/compliance review before execution
Cold storage signing	Air-gapped machines require manual transfer of signed transactions
Batch preparation	Prepare payroll or disbursements during business hours, execute overnight
Multi-sig coordination	Multiple approvers across time zones
Scheduled payments	Schedule payments to be executed at a future date

In traditional finance, a signed check doesn't expire in 90 seconds. Certain blockchain operations shouldn't either. Durable nonces solve this by replacing the recent blockhash with a stored, persistent value that only advances when you use it—giving you transactions that stay valid until you're ready to submit.

How It Works

Instead of a recent blockhash (valid ~150 blocks), you use a nonce account, a special account that stores a unique value. Each transaction using this nonce must "advance" it as the first instruction, preventing replay attacks.

┌─────────────────────────────────────────────────────────────────────────────┐
│  STANDARD BLOCKHASH                                                         │
│                                                                             │
│    ┌──────┐      ┌──────────┐                                               │
│    │ Sign │ ───▶ │  Submit  │     ⏱️ Must happen within ~90 seconds         │
│    └──────┘      └──────────┘                                               │
│       │                                                                     │
│       └─────────  Transaction expires if not submitted in time              │
└─────────────────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────────────────┐
│  DURABLE NONCE                                                              │
│                                                                             │
│    ┌──────┐      ┌───────┐       ┌─────────┐      ┌──────────┐              │
│    │ Sign │ ───▶ │ Store │ ───▶  │ Approve │ ───▶ │  Submit  │              │
│    └──────┘      └───────┘       └─────────┘      └──────────┘              │
│                                                                             │
│    Transaction remains valid until you submit it                            │
└─────────────────────────────────────────────────────────────────────────────┘

The nonce account costs ~0.0015 SOL for rent exemption. One nonce account = one pending transaction at a time. For parallel workflows, create multiple nonce accounts.

Setup: Create a Nonce Account

Creating a nonce account requires two instructions in a single transaction:

Create the account using getCreateAccountInstruction from the System Program
Initialize it as a nonce using getInitializeNonceAccountInstruction

import { generateKeyPairSigner } from "@solana/kit";
import {
  getNonceSize,
  getCreateAccountInstruction,
  getInitializeNonceAccountInstruction,
  SYSTEM_PROGRAM_ADDRESS
} from "@solana-program/system";

// Generate a keypair for the nonce account address
const nonceKeypair = await generateKeyPairSigner();

// Get required account size for rent calculation
const space = BigInt(getNonceSize());

// 1. Create the account (owned by System Program)
getCreateAccountInstruction({
  payer,
  newAccount: nonceKeypair,
  lamports: rent,
  space,
  programAddress: SYSTEM_PROGRAM_ADDRESS
});

// 2. Initialize as nonce account
getInitializeNonceAccountInstruction({
  nonceAccount: nonceKeypair.address,
  nonceAuthority: authorityAddress // Controls nonce advancement
});

// Assemble and send transaction to the network

Building a Deferred Transaction

Two key differences from standard transactions:

Use the nonce value as the blockhash
Add advanceNonceAccount as the first instruction

Fetch the Nonce Value

import { fetchNonce } from "@solana-program/system";

const nonceAccount = await fetchNonce(rpc, nonceAddress);
const nonceValue = nonceAccount.data.blockhash; // Use this as your "blockhash"

Set Transaction Lifetime with Nonce

Instead of using a recent blockhash that expires, use the nonce value:

import { setTransactionMessageLifetimeUsingBlockhash } from "@solana/kit";

setTransactionMessageLifetimeUsingBlockhash(
  {
    blockhash: nonceAccount.data.blockhash,
    lastValidBlockHeight: BigInt(2n ** 64n - 1n) // Effectively never expires
  },
  transactionMessage
);

Advance the Nonce (Required First Instruction)

Every durable nonce transaction must include advanceNonceAccount as its first instruction. This prevents replay attacks by invalidating the nonce value after use and updating the nonce value.

import { getAdvanceNonceAccountInstruction } from "@solana-program/system";

// MUST be the first instruction in your transaction
getAdvanceNonceAccountInstruction({
  nonceAccount: nonceAddress,
  nonceAuthority // Signer that controls the nonce
});

Sign and Store

After building, sign the transaction and serialize it for storage:

import {
  signTransactionMessageWithSigners,
  getTransactionEncoder,
  getBase64EncodedWireTransaction
} from "@solana/kit";

// Sign the transaction
const signedTx = await signTransactionMessageWithSigners(transactionMessage);

// Serialize for storage (database, file, etc.)
const txBytes = getTransactionEncoder().encode(signedTx);
const serialized = getBase64EncodedWireTransaction(txBytes);

Store the serialized string in your database—it remains valid until the nonce is advanced.

Multi-Party Approval Workflow

Deserialize the transaction to add additional signatures, then serialize again for storage or submission:

import {
  getBase64Decoder,
  getTransactionDecoder,
  getTransactionEncoder,
  getBase64EncodedWireTransaction
} from "@solana/kit";

// Deserialize the stored transaction
const txBytes = getBase64Decoder().decode(serializedString);
const partiallySignedTx = getTransactionDecoder().decode(txBytes);

// Each approver adds their signature
const fullySignedTx = await newSigner.signTransactions([partiallySignedTx]);

// Serialize again for storage
const txBytes = getTransactionEncoder().encode(fullySignedTx);
const serialized = getBase64EncodedWireTransaction(txBytes);

The transaction can be serialized, stored, and passed between approvers. Once all required signatures are collected, submit to the network.

Execute When Ready

When approvals are complete, send the serialized transaction to the network:

const signature = await rpc
  .sendTransaction(serializedTransaction, { encoding: "base64" })
  .send();

Each nonce can only be used once. If a transaction fails or you decide not to submit it, you must advance the nonce before preparing another transaction with the same nonce account.

Advancing a Used or Abandoned Nonce

To invalidate a pending transaction or prepare the nonce for reuse, advance it manually:

import { getAdvanceNonceAccountInstruction } from "@solana-program/system";

// Submit this instruction (with a regular blockhash) to invalidate any pending transaction
getAdvanceNonceAccountInstruction({
  nonceAccount: nonceAddress,
  nonceAuthority
});

This generates a new nonce value, making any transaction signed with the old value permanently invalid.

Production Considerations

Nonce account management:

Create a pool of nonce accounts for parallel transaction preparation
Track which nonces are "in use" (have pending signed transactions)
Implement nonce recycling after transactions are submitted or abandoned

Security:

The nonce authority controls whether transactions can be invalidated. Consider separating nonce authority from transaction signers for additional control and separation of duties
Anyone with the serialized transaction bytes can submit it to the network

Introduction to Durable Nonces

सामग्री तालिका