Mint cTokens - Kamino Docs

Mint cTokens (collateral tokens) by depositing assets into Kamino lending reserves. cTokens represent your deposit and accrue interest over time, which can be redeemed later for the underlying asset plus earned interest.

Minting cTokens

Deposit reserve liquidity to receive cTokens in your wallet.

1

Import Dependencies

import {
  createSolanaRpc,
  createSolanaRpcSubscriptions,
  address,
  pipe,
  createTransactionMessage,
  setTransactionMessageFeePayerSigner,
  setTransactionMessageLifetimeUsingBlockhash,
  appendTransactionMessageInstructions,
  signTransactionMessageWithSigners,
  assertIsTransactionWithinSizeLimit,
  sendAndConfirmTransactionFactory,
  getSignatureFromTransaction,
} from '@solana/kit';
import {
  KaminoMarket,
  KaminoAction,
  VanillaObligation,
  PROGRAM_ID,
  getCurrentLedgerInstant,
  getMedianSlotDurationInMsFromLastEpochs,
} from '@kamino-finance/klend-sdk';
import { parseKeypairFile } from '@kamino-finance/klend-sdk/dist/utils/signer.js';
import BN from 'bn.js';

2

Load Market and Initialize RPC

const KEYPAIR_FILE = '/path/to/your/keypair.json';
const signer = await parseKeypairFile(KEYPAIR_FILE);

const rpc = createSolanaRpc('https://api.mainnet-beta.solana.com');
const rpcSubscriptions = createSolanaRpcSubscriptions('wss://api.mainnet-beta.solana.com');
const marketPubkey = address('7u3HeHxYDLhnCoErrtycNokbQYbWGzLs6JSDqGAv5PfF'); // SOL/BTC Market

const market = await KaminoMarket.load(rpc, marketPubkey, await getMedianSlotDurationInMsFromLastEpochs());

3

Build Deposit Reserve Liquidity Instructions

Supply USDC to the reserve and receive its cTokens.

const usdcMint = address('EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v');
const usdcReserve = market!.getExistingFloatRateReserveByMint(usdcMint);

const mintAction = await KaminoAction.buildDepositReserveLiquidityTxns({
  kaminoMarket: market!,
  amount: new BN(1_000_000),
  reserveAddress: usdcReserve.address,
  owner: signer,
  obligation: new VanillaObligation(PROGRAM_ID),
  scopeRefreshConfig: undefined,
  currentLedgerInstant: await getCurrentLedgerInstant(rpc),
});

console.log('cToken mint:', usdcReserve.getCTokenMint());

This doesn’t open a borrow position, so the obligation prop is required by the type but unused. reserve.getCollateralExchangeRate() returns the current cTokens per token.

4

Build the Transaction

const { value: latestBlockhash } = await rpc.getLatestBlockhash({ commitment: 'finalized' }).send();

const transactionMessage = pipe(
  createTransactionMessage({ version: 0 }),
  (tx) => setTransactionMessageFeePayerSigner(signer, tx),
  (tx) => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx),
  (tx) => appendTransactionMessageInstructions(KaminoAction.actionToIxs(mintAction), tx)
);

5

Sign and Send

const signedTransaction = await signTransactionMessageWithSigners(transactionMessage);
assertIsTransactionWithinSizeLimit(signedTransaction);

await sendAndConfirmTransactionFactory({ rpc, rpcSubscriptions })(signedTransaction, {
  commitment: 'confirmed',
  skipPreflight: true,
});

console.log('cTokens minted! Signature:', getSignatureFromTransaction(signedTransaction));

Once the transaction is confirmed, the cTokens are in your wallet. They grow in value as borrowers pay interest, and can be redeemed for USDC plus the interest earned.