How to Sign with a Keychain Backend

Keychain provides one SolanaSigner interface across many key-management backends: in-memory keys, cloud KMS/HSM, and managed wallet services. Write your signing code once, then switch backends through configuration.

The example below signs and sends a transfer with an in-memory signer. The same code works with any backend that signs a transaction you own (most of them); only the signer's construction changes. Crossmint and Fordefi native modes rewrite or broadcast the transaction themselves, so they cannot act as a Kit client signer: call them through signAndSendTransaction() from @solana/keychain-core instead.

Kit

import { createClient, generateKeyPairSigner, lamports } from "@solana/kit";
import { createMemorySigner } from "@solana/keychain-memory";
import { rpcAirdrop, solanaRpc } from "@solana/kit-plugin-rpc";
import { airdropSigner, signer } from "@solana/kit-plugin-signer";
import { getTransferSolInstruction } from "@solana-program/system";

// Most Keychain backends return a `SolanaTransactionSigner`. Swap this
// in-memory signer for `createAwsKmsSigner`, `createVaultSigner`, ... and the
// rest of this file is identical.
const keychainSigner = await createMemorySigner({
  privateKey: crypto.getRandomValues(new Uint8Array(32)),
});

const recipient = await generateKeyPairSigner();

const client = await createClient()
  .use(signer(keychainSigner))
  .use(
    solanaRpc({
      rpcUrl: "http://localhost:8899",
      rpcSubscriptionsUrl: "ws://localhost:8900",
    }),
  )
  .use(rpcAirdrop())
  .use(airdropSigner(lamports(1_000_000_000n)));

const { context } = await client.sendTransaction([
  getTransferSolInstruction({
    source: keychainSigner,
    destination: recipient.address,
    amount: lamports(10_000_000n),
  }),
]);

console.log("Signature:", context.signature);

Console

Click to execute the code.

Kit

import { createClient, generateKeyPairSigner, lamports } from "@solana/kit";
import { createMemorySigner } from "@solana/keychain-memory";
import { rpcAirdrop, solanaRpc } from "@solana/kit-plugin-rpc";
import { airdropSigner, signer } from "@solana/kit-plugin-signer";
import { getTransferSolInstruction } from "@solana-program/system";

// Most Keychain backends return a `SolanaTransactionSigner`. Swap this
// in-memory signer for `createAwsKmsSigner`, `createVaultSigner`, ... and the
// rest of this file is identical.
const keychainSigner = await createMemorySigner({
  privateKey: crypto.getRandomValues(new Uint8Array(32)),
});

const recipient = await generateKeyPairSigner();

const client = await createClient()
  .use(signer(keychainSigner))
  .use(
    solanaRpc({
      rpcUrl: "http://localhost:8899",
      rpcSubscriptionsUrl: "ws://localhost:8900",
    }),
  )
  .use(rpcAirdrop())
  .use(airdropSigner(lamports(1_000_000_000n)));

const { context } = await client.sendTransaction([
  getTransferSolInstruction({
    source: keychainSigner,
    destination: recipient.address,
    amount: lamports(10_000_000n),
  }),
]);

console.log("Signature:", context.signature);

Console

Click to execute the code.

The in-memory signer holds a raw private key: use it for development and tests. In production, use a managed backend so keys stay in dedicated infrastructure. See Choosing a backend.

Use a production backend

To sign with a production backend, install its package (or the umbrella @solana/keychain) and construct the signer through the unified factory. For backends that sign a transaction you own, the signing code stays the same.

AWS KMS

import { createKeychainSigner } from "@solana/keychain";

const signer = await createKeychainSigner({
  backend: "aws-kms",
  keyId: "alias/my-solana-key",
  publicKey: "base58_public_key"
});

HashiCorp Vault

import { createKeychainSigner } from "@solana/keychain";

const signer = await createKeychainSigner({
  backend: "vault",
  vaultAddr: "https://vault.example.com:8200",
  vaultToken: "hvs.xxxxx",
  keyName: "my-solana-key",
  publicKey: "base58_public_key"
});

See the TypeScript guide for every backend's configuration, or Choosing a backend to compare custody models.