Comparing arbitrum with kamino

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skills/arbitrum/SKILL.md

Arbitrum

Arbitrum is the largest Ethereum L2 by TVL, running an optimistic rollup via the Nitro execution engine. Nitro compiles a modified Geth (go-ethereum) to WASM, enabling full EVM equivalence with fraud proofs. Arbitrum One targets general-purpose DeFi, Arbitrum Nova uses AnyTrust (data availability committee) for high-throughput gaming/social, and Orbit lets teams launch custom L3s settling to Arbitrum.

What You Probably Got Wrong

AI models trained before late 2024 carry stale assumptions about Arbitrum. These corrections are critical.

block.number returns the L1 block number, not L2 — On Arbitrum, block.number in Solidity returns the L1 Ethereum block number at the time the sequencer processed the transaction. Use ArbSys(0x64).arbBlockNumber() for the actual L2 block number.
block.timestamp is the L1 timestamp — Same issue. block.timestamp reflects L1 time. For L2ley timing use ArbSys(0x64).arbBlockNumber() and correlate.
Arbitrum does NOT have the same gas model as Ethereum — Every Arbitrum transaction pays two gas components: (1) L2 execution gas (similar to Ethereum but cheaper), and (2) L1 data posting cost (calldata compressed and posted to Ethereum). The L1 component often dominates for data-heavy transactions. Use NodeInterface.gasEstimateComponents() to get the breakdown.
You need --legacy for Foundry deployments — Arbitrum's sequencer does not support EIP-1559 type-2 transactions natively in forge scripts. Use --legacy flag or your deployment will fail with a cryptic RPC error.
msg.sender in cross-chain calls is aliased — When an L1 contract sends a message to L2 via retryable tickets, msg.sender on L2 is NOT the L1 contract address. It is the L1 address + 0x1111000000000000000000000000000000001111 (the "address alias"). This prevents L1/L2 address collision attacks.
Retryable tickets can fail silently — An L1-to-L2 retryable ticket that runs out of gas on L2 does NOT revert on L1. It sits in the retry buffer for 7 days. You must monitor and manually redeem failed retryables, or your cross-chain message is lost after the TTL.
Withdrawals take 7 days, not minutes — L2-to-L1 messages go through the optimistic rollup challenge period. After calling ArbSys.sendTxToL1(), the user must wait ~7 days, then execute the message on L1 via the Outbox contract. There is no fast path in the native bridge.
There is no mempool — Arbitrum uses a centralized sequencer that orders transactions on a first-come-first-served basis. There is no traditional mempool, so MEV extraction works differently (no frontrunning via gas price bidding).

Quick Start

Chain Configuration

import { defineChain } from "viem";
import { arbitrum, arbitrumNova, arbitrumSepolia } from "viem/chains";

// Arbitrum One — mainnet
// Chain ID: 42161
// RPC: https://arb1.arbitrum.io/rpc (public, rate-limited)

// Arbitrum Nova — AnyTrust chain for gaming/social
// Chain ID: 42170
// RPC: https://nova.arbitrum.io/rpc

// Arbitrum Sepolia — testnet
// Chain ID: 421614
// RPC: https://sepolia-rollup.arbitrum.io/rpc

Client Setup

import { createPublicClient, createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { arbitrum } from "viem/chains";

const publicClient = createPublicClient({
  chain: arbitrum,
  transport: http(process.env.ARBITRUM_RPC_URL),
});

const account = privateKeyToAccount(
  process.env.PRIVATE_KEY as `0x${string}`
);

const walletClient = createWalletClient({
  account,
  chain: arbitrum,
  transport: http(process.env.ARBITRUM_RPC_URL),
});

Chain Details

Property	Arbitrum One	Arbitrum Nova	Arbitrum Sepolia
Chain ID	42161	42170	421614
RPC	`https://arb1.arbitrum.io/rpc`	`https://nova.arbitrum.io/rpc`	`https://sepolia-rollup.arbitrum.io/rpc`
Explorer	`https://arbiscan.io`	`https://nova.arbiscan.io`	`https://sepolia.arbiscan.io`
Bridge	`https://bridge.arbitrum.io`	`https://bridge.arbitrum.io`	`https://bridge.arbitrum.io`
Native Token	ETH	ETH	ETH
Block Time	~0.25s	~0.25s	~0.25s
Finality	~7 days (challenge period)	~7 days	~7 days

Deployment

Foundry Deployment

The --legacy flag is required — Arbitrum's sequencer does not natively support EIP-1559 type-2 transaction envelopes in forge broadcast.

# Deploy to Arbitrum One
forge create src/MyContract.sol:MyContract \
  --rpc-url $ARBITRUM_RPC_URL \
  --private-key $PRIVATE_KEY \
  --legacy

# Deploy to Arbitrum Sepolia (testnet)
forge create src/MyContract.sol:MyContract \
  --rpc-url https://sepolia-rollup.arbitrum.io/rpc \
  --private-key $PRIVATE_KEY \
  --legacy

# Using forge script
forge script script/Deploy.s.sol:DeployScript \
  --rpc-url $ARBITRUM_RPC_URL \
  --private-key $PRIVATE_KEY \
  --broadcast \
  --legacy

Hardhat Deployment

// hardhat.config.ts
import { HardhatUserConfig } from "hardhat/config";

const config: HardhatUserConfig = {
  solidity: "0.8.24",
  networks: {
    arbitrumOne: {
      url: process.env.ARBITRUM_RPC_URL ?? "https://arb1.arbitrum.io/rpc",
      accounts: [process.env.PRIVATE_KEY!],
      chainId: 42161,
    },
    arbitrumSepolia: {
      url: "https://sepolia-rollup.arbitrum.io/rpc",
      accounts: [process.env.PRIVATE_KEY!],
      chainId: 421614,
    },
  },
  etherscan: {
    apiKey: {
      arbitrumOne: process.env.ARBISCAN_API_KEY!,
      arbitrumSepolia: process.env.ARBISCAN_API_KEY!,
    },
  },
};

export default config;

Contract Verification

# Verify on Arbiscan (Foundry)
forge verify-contract \
  --chain-id 42161 \
  --etherscan-api-key $ARBISCAN_API_KEY \
  --compiler-version v0.8.24 \
  $CONTRACT_ADDRESS \
  src/MyContract.sol:MyContract

# Verify with constructor args
forge verify-contract \
  --chain-id 42161 \
  --etherscan-api-key $ARBISCAN_API_KEY \
  --constructor-args $(cast abi-encode "constructor(address,uint256)" 0xYourAddress 1000) \
  $CONTRACT_ADDRESS \
  src/MyContract.sol:MyContract

# Verify on Sourcify
forge verify-contract \
  --chain-id 42161 \
  --verifier sourcify \
  $CONTRACT_ADDRESS \
  src/MyContract.sol:MyContract

Cross-Chain Messaging

L1 to L2: Retryable Tickets

Retryable tickets are Arbitrum's mechanism for sending messages from Ethereum L1 to Arbitrum L2. The L1 Inbox contract accepts the message and ETH for L2 gas, then the sequencer auto-executes it on L2.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface IInbox {
    /// @notice Create a retryable ticket to send an L1→L2 message
    /// @param to L2 destination address
    /// @param l2CallValue ETH value to send to L2 destination
    /// @param maxSubmissionCost Max cost for L2 submission (refund if overestimated)
    /// @param excessFeeRefundAddress L2 address to refund excess fees
    /// @param callValueRefundAddress L2 address to refund call value on failure
    /// @param gasLimit L2 gas limit for execution
    /// @param maxFeePerGas Max L2 gas price
    /// @param data L2 calldata
    function createRetryableTicket(
        address to,
        uint256 l2CallValue,
        uint256 maxSubmissionCost,
        address excessFeeRefundAddress,
        address callValueRefundAddress,
        uint256 gasLimit,
        uint256 maxFeePerGas,
        bytes calldata data
    ) external payable returns (uint256);
}

// TypeScript: send L1→L2 message via retryable ticket
import { createPublicClient, createWalletClient, http, parseEther } from "viem";
import { mainnet } from "viem/chains";

const INBOX = "0x4Dbd4fc535Ac27206064B68FfCf827b0A60BAB3f" as const;

const inboxAbi = [
  {
    name: "createRetryableTicket",
    type: "function",
    stateMutability: "payable",
    inputs: [
      { name: "to", type: "address" },
      { name: "l2CallValue", type: "uint256" },
      { name: "maxSubmissionCost", type: "uint256" },
      { name: "excessFeeRefundAddress", type: "address" },
      { name: "callValueRefundAddress", type: "address" },
      { name: "gasLimit", type: "uint256" },
      { name: "maxFeePerGas", type: "uint256" },
      { name: "data", type: "bytes" },
    ],
    outputs: [{ name: "", type: "uint256" }],
  },
] as const;

const l1PublicClient = createPublicClient({
  chain: mainnet,
  transport: http(process.env.ETHEREUM_RPC_URL),
});

const maxSubmissionCost = parseEther("0.001");
const gasLimit = 1_000_000n;
const maxFeePerGas = 100_000_000n; // 0.1 gwei

// Total ETH needed: l2CallValue + maxSubmissionCost + (gasLimit * maxFeePerGas)
const totalValue = 0n + maxSubmissionCost + gasLimit * maxFeePerGas;

const { request } = await l1PublicClient.simulateContract({
  address: INBOX,
  abi: inboxAbi,
  functionName: "createRetryableTicket",
  args: [
    "0xYourL2ContractAddress",     // to
    0n,                             // l2CallValue
    maxSubmissionCost,              // maxSubmissionCost
    account.address,                // excessFeeRefundAddress
    account.address,                // callValueRefundAddress
    gasLimit,                       // gasLimit
    maxFeePerGas,                   // maxFeePerGas
    "0x",                           // data (encoded L2 function call)
  ],
  value: totalValue,
  account: account.address,
});

const hash = await walletClient.writeContract(request);

L2 to L1: ArbSys.sendTxToL1

L2-to-L1 messages go through the 7-day challenge period before they can be executed on L1.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

interface IArbSys {
    /// @notice Send a transaction from L2 to L1
    /// @param destination L1 destination address
    /// @param data L1 calldata
    /// @return unique message ID
    function sendTxToL1(
        address destination,
        bytes calldata data
    ) external payable returns (uint256);

    /// @notice Get the current L2 block number
    function arbBlockNumber() external view returns (uint256);
}

// ArbSys is at a fixed precompile address on all Arbitrum chains
IArbSys constant ARBSYS = IArbSys(0x0000000000000000000000000000000000000064);

contract L2ToL1Sender {
    event L2ToL1MessageSent(uint256 indexed messageId, address destination);

    function sendMessageToL1(
        address l1Target,
        bytes calldata l1Calldata
    ) external payable {
        uint256 messageId = ARBSYS.sendTxToL1{value: msg.value}(
            l1Target,
            l1Calldata
        );
        emit L2ToL1MessageSent(messageId, l1Target);
    }
}

Address Aliasing

When an L1 contract sends a retryable ticket, the msg.sender seen on L2 is the aliased address:

L2 alias = L1 address + 0x1111000000000000000000000000000000001111

// Reverse the alias to get the original L1 sender
function undoL1ToL2Alias(address l2Address) internal pure returns (address) {
    uint160 offset = uint160(0x1111000000000000000000000000000000001111);
    unchecked {
        return address(uint160(l2Address) - offset);
    }
}

// Verify an L2 call came from a specific L1 contract
modifier onlyFromL1Contract(address expectedL1Sender) {
    require(
        undoL1ToL2Alias(msg.sender) == expectedL1Sender,
        "NOT_FROM_L1_CONTRACT"
    );
    _;
}

ArbOS Precompiles

Arbitrum provides system-level functionality through precompile contracts at fixed addresses. These are available on all Arbitrum chains.

ArbSys (0x0000000000000000000000000000000000000064)

Core system functions for L2 operations.

interface IArbSys {
    function arbBlockNumber() external view returns (uint256);
    function arbBlockHash(uint256 blockNumber) external view returns (bytes32);
    function arbChainID() external view returns (uint256);
    function arbOSVersion() external view returns (uint256);
    function sendTxToL1(address dest, bytes calldata data) external payable returns (uint256);
    function withdrawEth(address dest) external payable returns (uint256);
}

const arbSysAbi = [
  {
    name: "arbBlockNumber",
    type: "function",
    stateMutability: "view",
    inputs: [],
    outputs: [{ name: "", type: "uint256" }],
  },
  {
    name: "withdrawEth",
    type: "function",
    stateMutability: "payable",
    inputs: [{ name: "destination", type: "address" }],
    outputs: [{ name: "", type: "uint256" }],
  },
] as const;

const ARBSYS = "0x0000000000000000000000000000000000000064" as const;

const l2BlockNumber = await publicClient.readContract({
  address: ARBSYS,
  abi: arbSysAbi,
  functionName: "arbBlockNumber",
});

ArbRetryableTx (0x000000000000000000000000000000000000006E)

Manage retryable tickets on L2.

interface IArbRetryableTx {
    /// @notice Redeem a retryable ticket that failed auto-execution
    function redeem(bytes32 ticketId) external;
    /// @notice Get the TTL for retryable tickets (default: 7 days)
    function getLifetime() external view returns (uint256);
    /// @notice Get the timeout timestamp for a specific ticket
    function getTimeout(bytes32 ticketId) external view returns (uint256);
    /// @notice Extend the lifetime of a retryable ticket
    function keepalive(bytes32 ticketId) external returns (uint256);
}

ArbGasInfo (0x000000000000000000000000000000000000006C)

Gas pricing information, especially the L1 data cost component.

interface IArbGasInfo {
    /// @notice Get gas prices: [perL2Tx, perL1CalldataUnit, perStorageAlloc, perArbGasBase, perArbGasCongestion, perArbGasTotal]
    function getPricesInWei() external view returns (uint256, uint256, uint256, uint256, uint256, uint256);
    /// @notice Get estimated L1 base fee
    function getL1BaseFeeEstimate() external view returns (uint256);
    /// @notice Get L1 gas pricing parameters
    function getL1GasPriceEstimate() external view returns (uint256);
}

const arbGasInfoAbi = [
  {
    name: "getPricesInWei",
    type: "function",
    stateMutability: "view",
    inputs: [],
    outputs: [
      { name: "perL2Tx", type: "uint256" },
      { name: "perL1CalldataUnit", type: "uint256" },
      { name: "perStorageAlloc", type: "uint256" },
      { name: "perArbGasBase", type: "uint256" },
      { name: "perArbGasCongestion", type: "uint256" },
      { name: "perArbGasTotal", type: "uint256" },
    ],
  },
  {
    name: "getL1BaseFeeEstimate",
    type: "function",
    stateMutability: "view",
    inputs: [],
    outputs: [{ name: "", type: "uint256" }],
  },
] as const;

const ARBGASINFO = "0x000000000000000000000000000000000000006C" as const;

const prices = await publicClient.readContract({
  address: ARBGASINFO,
  abi: arbGasInfoAbi,
  functionName: "getPricesInWei",
});

const l1BaseFee = await publicClient.readContract({
  address: ARBGASINFO,
  abi: arbGasInfoAbi,
  functionName: "getL1BaseFeeEstimate",
});

NodeInterface (0x00000000000000000000000000000000000000C8)

Virtual contract for gas estimation — not callable from other contracts, only via eth_call / eth_estimateGas.

interface INodeInterface {
    /// @notice Estimate gas for a retryable ticket submission
    function estimateRetryableTicket(
        address sender,
        uint256 deposit,
        address to,
        uint256 l2CallValue,
        address excessFeeRefundAddress,
        address callValueRefundAddress,
        bytes calldata data
    ) external;

    /// @notice Get gas cost breakdown: gasEstimate, gasEstimateForL1, baseFee, l1BaseFeeEstimate
    function gasEstimateComponents(
        address to,
        bool contractCreation,
        bytes calldata data
    ) external payable returns (uint64, uint64, uint256, uint256);
}

const nodeInterfaceAbi = [
  {
    name: "gasEstimateComponents",
    type: "function",
    stateMutability: "payable",
    inputs: [
      { name: "to", type: "address" },
      { name: "contractCreation", type: "bool" },
      { name: "data", type: "bytes" },
    ],
    outputs: [
      { name: "gasEstimate", type: "uint64" },
      { name: "gasEstimateForL1", type: "uint64" },
      { name: "baseFee", type: "uint256" },
      { name: "l1BaseFeeEstimate", type: "uint256" },
    ],
  },
] as const;

const NODE_INTERFACE = "0x00000000000000000000000000000000000000C8" as const;

// Estimate gas with L1/L2 breakdown
const result = await publicClient.simulateContract({
  address: NODE_INTERFACE,
  abi: nodeInterfaceAbi,
  functionName: "gasEstimateComponents",
  args: [
    "0xTargetContract",
    false,
    "0xEncodedCalldata",
  ],
});

const [totalGas, l1Gas, baseFee, l1BaseFee] = result.result;
// L2 gas = totalGas - l1Gas

Gas Model

Arbitrum's gas model has two components. Understanding this is critical for accurate cost estimation.

Two-Component Gas

Component	Source	Scales With
L2 execution gas	ArbOS computation	Opcodes executed (similar to Ethereum)
L1 data posting cost	Calldata posted to Ethereum	Transaction size in bytes

The L1 data cost is computed as:

L1 cost = L1 base fee * (calldata bytes * 16 + overhead)

This L1 cost is converted to L2 gas units and added to the total gas used. For data-heavy transactions (large calldata, many storage writes that get batched), the L1 component can be 80%+ of total cost.

Gas Estimation

import { encodeFunctionData, formatEther } from "viem";

async function estimateArbitrumGas(
  publicClient: PublicClient,
  to: `0x${string}`,
  data: `0x${string}`
) {
  const nodeInterfaceAbi = [
    {
      name: "gasEstimateComponents",
      type: "function",
      stateMutability: "payable",
      inputs: [
        { name: "to", type: "address" },
        { name: "contractCreation", type: "bool" },
        { name: "data", type: "bytes" },
      ],
      outputs: [
        { name: "gasEstimate", type: "uint64" },
        { name: "gasEstimateForL1", type: "uint64" },
        { name: "baseFee", type: "uint256" },
        { name: "l1BaseFeeEstimate", type: "uint256" },
      ],
    },
  ] as const;

  const { result } = await publicClient.simulateContract({
    address: "0x00000000000000000000000000000000000000C8",
    abi: nodeInterfaceAbi,
    functionName: "gasEstimateComponents",
    args: [to, false, data],
  });

  const [totalGas, l1Gas, baseFee, l1BaseFee] = result;
  const l2Gas = totalGas - l1Gas;

  return {
    totalGas,
    l1Gas,
    l2Gas,
    baseFee,
    l1BaseFee,
    estimatedCostWei: BigInt(totalGas) * baseFee,
    estimatedCostEth: formatEther(BigInt(totalGas) * baseFee),
  };
}

Token Bridge

Bridging ETH (L1 to L2)

const INBOX = "0x4Dbd4fc535Ac27206064B68FfCf827b0A60BAB3f" as const;

const inboxAbi = [
  {
    name: "depositEth",
    type: "function",
    stateMutability: "payable",
    inputs: [],
    outputs: [{ name: "", type: "uint256" }],
  },
] as const;

// Deposit 0.1 ETH from L1 to L2 (arrives at same address on L2)
const { request } = await l1PublicClient.simulateContract({
  address: INBOX,
  abi: inboxAbi,
  functionName: "depositEth",
  value: parseEther("0.1"),
  account: account.address,
});

const hash = await l1WalletClient.writeContract(request);
const receipt = await l1PublicClient.waitForTransactionReceipt({ hash });
if (receipt.status !== "success") throw new Error("ETH deposit failed");
// ETH appears on L2 within ~10 minutes

Bridging ETH (L2 to L1)

// Withdraw ETH from L2 to L1 via ArbSys precompile
const ARBSYS = "0x0000000000000000000000000000000000000064" as const;

const arbSysAbi = [
  {
    name: "withdrawEth",
    type: "function",
    stateMutability: "payable",
    inputs: [{ name: "destination", type: "address" }],
    outputs: [{ name: "", type: "uint256" }],
  },
] as const;

const { request } = await l2PublicClient.simulateContract({
  address: ARBSYS,
  abi: arbSysAbi,
  functionName: "withdrawEth",
  args: [account.address], // L1 destination
  value: parseEther("0.1"),
  account: account.address,
});

const hash = await l2WalletClient.writeContract(request);
// After 7-day challenge period, claim on L1 via Outbox contract

Bridging ERC20 Tokens (L1 to L2)

ERC20 tokens bridge through the Gateway Router, which routes to the appropriate gateway (standard, custom, or WETH).

const GATEWAY_ROUTER = "0x72Ce9c846789fdB6fC1f34aC4AD25Dd9ef7031ef" as const;

const gatewayRouterAbi = [
  {
    name: "outboundTransfer",
    type: "function",
    stateMutability: "payable",
    inputs: [
      { name: "_token", type: "address" },
      { name: "_to", type: "address" },
      { name: "_amount", type: "uint256" },
      { name: "_maxGas", type: "uint256" },
      { name: "_gasPriceBid", type: "uint256" },
      { name: "_data", type: "bytes" },
    ],
    outputs: [{ name: "", type: "bytes" }],
  },
  {
    name: "getGateway",
    type: "function",
    stateMutability: "view",
    inputs: [{ name: "_token", type: "address" }],
    outputs: [{ name: "", type: "address" }],
  },
] as const;

const USDC_L1 = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" as const;

// Step 1: Approve the gateway (not the router) to spend tokens
const gateway = await l1PublicClient.readContract({
  address: GATEWAY_ROUTER,
  abi: gatewayRouterAbi,
  functionName: "getGateway",
  args: [USDC_L1],
});

// Step 2: approve gateway, then call outboundTransfer on the router
// The _data param encodes maxSubmissionCost and extra data
import { encodeAbiParameters, parseAbiParameters } from "viem";

const maxSubmissionCost = parseEther("0.001");
const extraData = encodeAbiParameters(
  parseAbiParameters("uint256, bytes"),
  [maxSubmissionCost, "0x"]
);

const bridgeAmount = 1000_000000n; // 1000 USDC (6 decimals)
const gasLimit = 300_000n;
const gasPriceBid = 100_000_000n; // 0.1 gwei

const totalValue = maxSubmissionCost + gasLimit * gasPriceBid;

const { request } = await l1PublicClient.simulateContract({
  address: GATEWAY_ROUTER,
  abi: gatewayRouterAbi,
  functionName: "outboundTransfer",
  args: [
    USDC_L1,
    account.address,
    bridgeAmount,
    gasLimit,
    gasPriceBid,
    extraData,
  ],
  value: totalValue,
  account: account.address,
});

Gateway Types

Gateway	Address (L1)	Purpose
Standard ERC20	`0xa3A7B6F88361F48403514059F1F16C8E78d60EeC`	Default for most ERC20 tokens
Custom	Varies per token	Tokens needing custom L1/L2 logic
WETH	`0xd92023E9d9911199a6711321D1277285e6d4e2db`	Handles WETH unwrap/wrap across bridge

Orbit Chains

Orbit allows teams to launch custom L3 chains that settle to Arbitrum One or Nova. These are independent chains with configurable parameters.

Orbit Architecture

Ethereum L1 (settlement)
  └── Arbitrum One L2 (execution + DA)
       └── Your Orbit L3 (custom chain)

Orbit SDK Setup

import { createRollupPrepareConfig, createRollupPrepareTransactionRequest } from "@arbitrum/orbit-sdk";

// Prepare Orbit chain configuration
const config = createRollupPrepareConfig({
  chainId: BigInt(YOUR_CHAIN_ID),
  owner: "0xYourOwnerAddress",
  chainConfig: {
    // Custom gas token, data availability, etc.
    homesteadBlock: 0,
    daoForkBlock: null,
    daoForkSupport: true,
    eip150Block: 0,
    eip150Hash: "0x0000000000000000000000000000000000000000000000000000000000000000",
    eip155Block: 0,
    eip158Block: 0,
    byzantiumBlock: 0,
    constantinopleBlock: 0,
    petersburgBlock: 0,
    istanbulBlock: 0,
    muirGlacierBlock: 0,
    berlinBlock: 0,
    londonBlock: 0,
    clique: { period: 0, epoch: 0 },
    arbitrum: {
      EnableArbOS: true,
      AllowDebugPrecompiles: false,
      DataAvailabilityCommittee: false, // true for AnyTrust
      InitialArbOSVersion: 20,
      InitialChainOwner: "0xYourOwnerAddress",
      GenesisBlockNum: 0,
    },
  },
});

When to Use Orbit

Use Case	Recommendation
App-specific chain with custom gas token	Orbit L3
High-throughput gaming with cheap DA	Orbit L3 + AnyTrust
General DeFi app	Deploy to Arbitrum One directly
Cross-chain interop needed	Deploy to Arbitrum One (better liquidity)

Key Differences from Ethereum

Behavior	Ethereum	Arbitrum
`block.number`	Current L1 block	L1 block number (NOT L2)
`block.timestamp`	L1 timestamp	L1 timestamp
L2 block number	N/A	`ArbSys(0x64).arbBlockNumber()`
Gas model	Single gas price	L2 gas + L1 data posting cost
Transaction type	EIP-1559 (type 2)	Legacy (type 0) recommended
Mempool	Public, competitive	No mempool (FCFS sequencer)
Finality	~12 seconds (1 epoch)	~0.25s soft, ~7 days hard
`msg.sender` cross-chain	Same address	Aliased (+0x1111...1111 offset)
`SELFDESTRUCT`	Deprecated (EIP-6780)	Same as Ethereum post-Dencun
Contract size limit	24KB (EIP-170)	24KB (same)
`PUSH0` opcode	Supported (Shanghai)	Supported (Nitro supports it)

Contract Addresses

Last verified: February 2026

Core Contracts (Arbitrum One)

Contract	Address
Rollup	`0x5eF0D09d1E6204141B4d37530808eD19f60FBa35`
Inbox	`0x4Dbd4fc535Ac27206064B68FfCf827b0A60BAB3f`
Outbox	`0x0B9857ae2D4A3DBe74ffE1d7DF045bb7F96E4840`
Bridge	`0x8315177aB297bA92A06054cE80a67Ed4DBd7ed3a`
SequencerInbox	`0x1c479675ad559DC151F6Ec7ed3FbF8ceE79582B6`
Gateway Router (L1)	`0x72Ce9c846789fdB6fC1f34aC4AD25Dd9ef7031ef`
Standard Gateway (L1)	`0xa3A7B6F88361F48403514059F1F16C8E78d60EeC`
WETH Gateway (L1)	`0xd92023E9d9911199a6711321D1277285e6d4e2db`
Gateway Router (L2)	`0x5288c571Fd7aD117beA99bF60FE0846C4E84F933`
Standard Gateway (L2)	`0x09e9222E96E7B4AE2a407B98d48e330053351EEe`

ArbOS Precompiles

Precompile	Address
ArbSys	`0x0000000000000000000000000000000000000064`
ArbInfo	`0x0000000000000000000000000000000000000065`
ArbAddressTable	`0x0000000000000000000000000000000000000066`
ArbBLS (deprecated)	`0x0000000000000000000000000000000000000067`
ArbFunctionTable (deprecated)	`0x0000000000000000000000000000000000000068`
ArbosTest	`0x0000000000000000000000000000000000000069`
ArbOwner	`0x0000000000000000000000000000000000000070`
ArbGasInfo	`0x000000000000000000000000000000000000006C`
ArbAggregator	`0x000000000000000000000000000000000000006D`
ArbRetryableTx	`0x000000000000000000000000000000000000006E`
ArbStatistics	`0x000000000000000000000000000000000000006F`
NodeInterface	`0x00000000000000000000000000000000000000C8`

Token Addresses (Arbitrum One)

Token	Address
ARB	`0x912CE59144191C1204E64559FE8253a0e49E6548`
WETH	`0x82aF49447D8a07e3bd95BD0d56f35241523fBab1`
USDC (native)	`0xaf88d065e77c8cC2239327C5EDb3A432268e5831`
USDC.e (bridged)	`0xFF970A61A04b1cA14834A43f5dE4533eBDDB5CC8`
USDT	`0xFd086bC7CD5C481DCC9C85ebE478A1C0b69FCbb9`
DAI	`0xDA10009cBd5D07dd0CeCc66161FC93D7c9000da1`
WBTC	`0x2f2a2543B76A4166549F7aaB2e75Bef0aefC5B0f`
GMX	`0xfc5A1A6EB076a2C7aD06eD22C90d7E710E35ad0a`

Error Handling

Error	Cause	Fix
`NOT_ENOUGH_FUNDS`	Insufficient ETH for L2 gas + L1 data cost	Account for both gas components in estimation
`RETRYABLE_TICKET_CREATION_FAILED`	Retryable ticket underfunded	Increase `maxSubmissionCost` or `gasLimit * maxFeePerGas`
`ONLY_ROLLUP_OR_OWNER`	Calling admin precompile without permission	These are restricted to chain owner
`NO_TICKET_WITH_ID`	Redeeming non-existent or expired retryable	Check ticket still exists with `getTimeout()`
`ALREADY_REDEEMED`	Retryable ticket already executed	No action needed — message was delivered
`L1_MSG_NOT_CONFIRMED`	Trying to execute L2→L1 message too early	Wait for the 7-day challenge period to elapse
Nonce too high/low	Sequencer nonce mismatch	Reset nonce or wait for pending transactions

Security

Cross-Chain Message Validation

// Always verify the sender of cross-chain messages
// L1→L2: check aliased sender
modifier onlyL1Contract(address expectedL1Sender) {
    uint160 offset = uint160(0x1111000000000000000000000000000000001111);
    unchecked {
        require(
            address(uint160(msg.sender) - offset) == expectedL1Sender,
            "ONLY_L1_CONTRACT"
        );
    }
    _;
}

// L2→L1: verify via Outbox on L1
modifier onlyL2Contract(address outbox) {
    // The Outbox contract provides l2ToL1Sender() during execution
    IOutbox(outbox).l2ToL1Sender();
    _;
}

Gas Estimation Safety

Always use NodeInterface.gasEstimateComponents() instead of plain eth_estimateGas — the latter may not account for L1 data costs correctly in all cases.
Add a 20-30% buffer to gas estimates for L1 data cost fluctuations.
For retryable tickets, overestimate maxSubmissionCost — excess is refunded.

Retryable Ticket Monitoring

Monitor all retryable tickets for auto-redeem failure.
Failed retryables expire after 7 days — set up alerts.
Use the ArbRetryableTx precompile to check status and manually redeem.

References

kamino

View full →

Author

@0xinit

Stars

Repository

0xinit/cryptoskills

skills/kamino/SKILL.md

Kamino Finance Development Guide

Build sophisticated DeFi applications on Solana with Kamino Finance - the comprehensive DeFi protocol offering lending, borrowing, automated liquidity management, leverage trading, and oracle aggregation.

Overview

Kamino Finance provides:

Kamino Lend (K-Lend): Lending and borrowing protocol with isolated markets
Kamino Liquidity (K-Liquidity): Automated CLMM liquidity management strategies
Scope Oracle: Oracle price aggregator for reliable pricing
Multiply/Leverage: Leveraged long/short positions on assets
Vaults: Yield-generating vault strategies
Obligation Orders: Automated LTV-based and price-based order execution

Quick Start

Installation

# Lending SDK
npm install @kamino-finance/klend-sdk

# Liquidity SDK
npm install @kamino-finance/kliquidity-sdk

# Oracle SDK
npm install @kamino-finance/scope-sdk

# Required peer dependencies
npm install @solana/web3.js @coral-xyz/anchor decimal.js

Environment Setup

# .env file
SOLANA_RPC_URL=https://api.mainnet-beta.solana.com
WALLET_KEYPAIR_PATH=./keypair.json

Kamino Lending (klend-sdk)

The lending SDK enables interaction with Kamino's lending markets for deposits, borrows, repayments, and liquidations.

Core Classes

Class	Purpose
`KaminoMarket`	Load and interact with lending markets
`KaminoAction`	Build lending transactions (deposit, borrow, repay, withdraw)
`KaminoObligation`	Manage user obligations (positions)
`KaminoReserve`	Access reserve configurations and stats
`VanillaObligation`	Standard obligation type

Initialize Market

import { KaminoMarket } from "@kamino-finance/klend-sdk";
import { Connection, PublicKey } from "@solana/web3.js";

const connection = new Connection("https://api.mainnet-beta.solana.com");

// Main lending market address
const MAIN_MARKET = new PublicKey("7u3HeHxYDLhnCoErrtycNokbQYbWGzLs6JSDqGAv5PfF");

// Load market with basic data
const market = await KaminoMarket.load(connection, MAIN_MARKET);

// Load reserves for detailed data
await market.loadReserves();

// Get specific reserve
const usdcReserve = market.getReserve("USDC");
console.log("Total Deposits:", usdcReserve?.stats.totalDepositsWads.toString());
console.log("LTV:", usdcReserve?.stats.loanToValueRatio);
console.log("Borrow APY:", usdcReserve?.stats.borrowInterestAPY);
console.log("Supply APY:", usdcReserve?.stats.supplyInterestAPY);

// Refresh all data including obligations
await market.refreshAll();

Deposit Collateral

import { KaminoAction, VanillaObligation, PROGRAM_ID } from "@kamino-finance/klend-sdk";
import { Keypair, sendAndConfirmTransaction } from "@solana/web3.js";
import Decimal from "decimal.js";

async function deposit(
  market: KaminoMarket,
  wallet: Keypair,
  tokenSymbol: string,
  amount: Decimal
) {
  // Build deposit transaction
  const kaminoAction = await KaminoAction.buildDepositTxns(
    market,
    amount.toString(),           // Amount in base units
    tokenSymbol,                  // e.g., "USDC", "SOL"
    wallet.publicKey,
    new VanillaObligation(PROGRAM_ID),
    0,                            // Additional compute budget (optional)
    true,                         // Include Ata init instructions
    undefined,                    // Referrer (optional)
    undefined,                    // Current slot (optional)
    "finalized"                   // Commitment
  );

  // Get all instructions
  const instructions = [
    ...kaminoAction.setupIxs,
    ...kaminoAction.lendingIxs,
    ...kaminoAction.cleanupIxs,
  ];

  // Create and send transaction
  const tx = new Transaction().add(...instructions);
  const signature = await sendAndConfirmTransaction(connection, tx, [wallet]);

  return signature;
}

Borrow Assets

async function borrow(
  market: KaminoMarket,
  wallet: Keypair,
  tokenSymbol: string,
  amount: Decimal
) {
  const kaminoAction = await KaminoAction.buildBorrowTxns(
    market,
    amount.toString(),
    tokenSymbol,
    wallet.publicKey,
    new VanillaObligation(PROGRAM_ID),
    0,
    true,
    false,                        // Include deposit for fees (optional)
    undefined,
    undefined,
    "finalized"
  );

  const instructions = [
    ...kaminoAction.setupIxs,
    ...kaminoAction.lendingIxs,
    ...kaminoAction.cleanupIxs,
  ];

  const tx = new Transaction().add(...instructions);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Repay Loan

async function repay(
  market: KaminoMarket,
  wallet: Keypair,
  tokenSymbol: string,
  amount: Decimal | "max"
) {
  const repayAmount = amount === "max" ? "max" : amount.toString();

  const kaminoAction = await KaminoAction.buildRepayTxns(
    market,
    repayAmount,
    tokenSymbol,
    wallet.publicKey,
    new VanillaObligation(PROGRAM_ID),
    0,
    true,
    undefined,
    "finalized"
  );

  const instructions = [
    ...kaminoAction.setupIxs,
    ...kaminoAction.lendingIxs,
    ...kaminoAction.cleanupIxs,
  ];

  const tx = new Transaction().add(...instructions);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Withdraw Collateral

async function withdraw(
  market: KaminoMarket,
  wallet: Keypair,
  tokenSymbol: string,
  amount: Decimal | "max"
) {
  const withdrawAmount = amount === "max" ? "max" : amount.toString();

  const kaminoAction = await KaminoAction.buildWithdrawTxns(
    market,
    withdrawAmount,
    tokenSymbol,
    wallet.publicKey,
    new VanillaObligation(PROGRAM_ID),
    0,
    true,
    undefined,
    "finalized"
  );

  const instructions = [
    ...kaminoAction.setupIxs,
    ...kaminoAction.lendingIxs,
    ...kaminoAction.cleanupIxs,
  ];

  const tx = new Transaction().add(...instructions);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Get User Obligations

// Get single vanilla obligation for user
const obligation = await market.getUserVanillaObligation(wallet.publicKey);

if (obligation) {
  console.log("Deposits:", obligation.state.deposits);
  console.log("Borrows:", obligation.state.borrows);
  console.log("Health Factor:", obligation.refreshedStats.borrowLimit);
}

// Get all obligations for user
const allObligations = await market.getAllUserObligations(wallet.publicKey);

// Get obligations for specific reserve
const reserveObligations = await market.getAllUserObligationsForReserve(
  wallet.publicKey,
  usdcReserve
);

// Check if reserve is part of obligation
const isReserveInObligation = market.isReserveInObligation(
  obligation,
  usdcReserve
);

Liquidation

async function liquidate(
  market: KaminoMarket,
  liquidator: Keypair,
  obligationOwner: PublicKey,
  repayTokenSymbol: string,
  withdrawTokenSymbol: string,
  repayAmount: Decimal
) {
  const kaminoAction = await KaminoAction.buildLiquidateTxns(
    market,
    repayAmount.toString(),
    repayTokenSymbol,
    withdrawTokenSymbol,
    obligationOwner,
    liquidator.publicKey,
    new VanillaObligation(PROGRAM_ID),
    0,
    true,
    "finalized"
  );

  const instructions = [
    ...kaminoAction.setupIxs,
    ...kaminoAction.lendingIxs,
    ...kaminoAction.cleanupIxs,
  ];

  const tx = new Transaction().add(...instructions);
  return await sendAndConfirmTransaction(connection, tx, [liquidator]);
}

Leverage/Multiply Operations

Kamino supports leveraged positions through the multiply feature.

Open Leveraged Position

import {
  getLeverageDepositIxns,
  getLeverageWithdrawIxns,
  calculateLeverageMultiplier
} from "@kamino-finance/klend-sdk/leverage";

async function openLeveragedPosition(
  market: KaminoMarket,
  wallet: Keypair,
  collateralToken: string,
  borrowToken: string,
  depositAmount: Decimal,
  targetLeverage: number  // e.g., 2x, 3x
) {
  // Calculate parameters for target leverage
  const leverageParams = await calculateLeverageMultiplier(
    market,
    collateralToken,
    borrowToken,
    depositAmount,
    targetLeverage
  );

  // Build leverage deposit instructions
  const { instructions, lookupTables } = await getLeverageDepositIxns(
    market,
    wallet.publicKey,
    collateralToken,
    borrowToken,
    depositAmount,
    leverageParams,
    new VanillaObligation(PROGRAM_ID)
  );

  // Execute transaction with address lookup tables
  const tx = new VersionedTransaction(/* ... */);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Close Leveraged Position

async function closeLeveragedPosition(
  market: KaminoMarket,
  wallet: Keypair,
  collateralToken: string,
  borrowToken: string
) {
  const { instructions, lookupTables } = await getLeverageWithdrawIxns(
    market,
    wallet.publicKey,
    collateralToken,
    borrowToken,
    "max",  // Withdraw full position
    new VanillaObligation(PROGRAM_ID)
  );

  const tx = new VersionedTransaction(/* ... */);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Obligation Orders

Automate actions based on LTV or price thresholds.

LTV-Based Orders

import {
  createLtvBasedOrder,
  LtvOrderType
} from "@kamino-finance/klend-sdk/obligation_orders";

// Create order to repay when LTV exceeds threshold
async function createLtvOrder(
  market: KaminoMarket,
  wallet: Keypair,
  targetLtv: number,  // e.g., 0.8 for 80%
  repayToken: string,
  repayAmount: Decimal
) {
  const orderIx = await createLtvBasedOrder(
    market,
    wallet.publicKey,
    new VanillaObligation(PROGRAM_ID),
    {
      type: LtvOrderType.REPAY_ON_HIGH_LTV,
      triggerLtv: targetLtv,
      repayToken,
      repayAmount: repayAmount.toString(),
    }
  );

  const tx = new Transaction().add(orderIx);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Price-Based Orders

import {
  createPriceBasedOrder,
  PriceOrderType
} from "@kamino-finance/klend-sdk/obligation_orders";

// Create stop-loss order
async function createStopLossOrder(
  market: KaminoMarket,
  wallet: Keypair,
  tokenSymbol: string,
  triggerPrice: Decimal,
  action: "repay" | "withdraw"
) {
  const orderIx = await createPriceBasedOrder(
    market,
    wallet.publicKey,
    new VanillaObligation(PROGRAM_ID),
    {
      type: PriceOrderType.STOP_LOSS,
      tokenSymbol,
      triggerPrice: triggerPrice.toString(),
      action,
    }
  );

  const tx = new Transaction().add(orderIx);
  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Kamino Liquidity (kliquidity-sdk)

Automated liquidity management for concentrated liquidity positions on Orca, Raydium, and Meteora.

Initialize SDK

import { Kamino } from "@kamino-finance/kliquidity-sdk";
import { Connection, clusterApiUrl } from "@solana/web3.js";

const connection = new Connection(clusterApiUrl("mainnet-beta"));
const kamino = new Kamino("mainnet-beta", connection);

Fetch Strategies

// Get all strategies
const strategies = await kamino.getStrategies();

// Get strategy by address
const strategy = await kamino.getStrategyByAddress(
  new PublicKey("strategy_address")
);

// Get strategy by kToken mint
const strategyByMint = await kamino.getStrategyByKTokenMint(
  new PublicKey("ktoken_mint")
);

// Get strategies with filters
const filteredStrategies = await kamino.getAllStrategiesWithFilters({
  strategyType: "NON_PEGGED",   // NON_PEGGED, PEGGED, STABLE
  status: "LIVE",               // LIVE, STAGING, DEPRECATED
  tokenA: new PublicKey("..."), // Filter by token A
  tokenB: new PublicKey("..."), // Filter by token B
});

Strategy Types

Type	Description	Example Pairs
`NON_PEGGED`	Uncorrelated assets	SOL-BONK, SOL-USDC
`PEGGED`	Loosely correlated	BSOL-JitoSOL, mSOL-SOL
`STABLE`	Price-stable	USDC-USDT, USDH-USDC

Get Strategy Data

// Get share price
const sharePrice = await kamino.getStrategySharePrice(strategy);
console.log("Share Price:", sharePrice.toString());

// Get share data
const shareData = await kamino.getStrategyShareData(strategy);
console.log("Total Shares:", shareData.totalShares);
console.log("Token A per Share:", shareData.tokenAPerShare);
console.log("Token B per Share:", shareData.tokenBPerShare);

// Get token amounts per share
const tokenAmounts = await kamino.getTokenAAndBPerShare(strategy);
console.log("Token A:", tokenAmounts.tokenA);
console.log("Token B:", tokenAmounts.tokenB);

// Get strategy price range
const range = await kamino.getStrategyRange(strategy);
console.log("Lower Price:", range.lowerPrice);
console.log("Upper Price:", range.upperPrice);
console.log("Current Price:", range.currentPrice);

Deposit to Strategy

import Decimal from "decimal.js";

async function depositToStrategy(
  kamino: Kamino,
  wallet: Keypair,
  strategyAddress: PublicKey,
  tokenAAmount: Decimal,
  tokenBAmount: Decimal,
  slippage: Decimal  // e.g., new Decimal(0.01) for 1%
) {
  const strategy = await kamino.getStrategyByAddress(strategyAddress);

  // Build deposit instructions
  const depositIxs = await kamino.deposit(
    strategy,
    wallet.publicKey,
    tokenAAmount,
    tokenBAmount,
    slippage
  );

  // Create transaction with extra compute budget
  const tx = kamino.createTransactionWithExtraBudget();
  tx.add(...depositIxs);

  await kamino.assignBlockInfoToTransaction(tx);

  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Single Token Deposit

async function singleTokenDeposit(
  kamino: Kamino,
  wallet: Keypair,
  strategyAddress: PublicKey,
  tokenAmount: Decimal,
  isTokenA: boolean,  // true for Token A, false for Token B
  slippage: Decimal
) {
  const strategy = await kamino.getStrategyByAddress(strategyAddress);

  const depositIxs = await kamino.singleTokenDeposit(
    strategy,
    wallet.publicKey,
    tokenAmount,
    isTokenA,
    slippage
  );

  const tx = kamino.createTransactionWithExtraBudget();
  tx.add(...depositIxs);

  await kamino.assignBlockInfoToTransaction(tx);

  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Withdraw from Strategy

async function withdrawFromStrategy(
  kamino: Kamino,
  wallet: Keypair,
  strategyAddress: PublicKey,
  shareAmount: Decimal,  // Number of shares to withdraw
  slippage: Decimal
) {
  const strategy = await kamino.getStrategyByAddress(strategyAddress);

  const withdrawIxs = await kamino.withdraw(
    strategy,
    wallet.publicKey,
    shareAmount,
    slippage
  );

  const tx = kamino.createTransactionWithExtraBudget();
  tx.add(...withdrawIxs);

  await kamino.assignBlockInfoToTransaction(tx);

  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

// Withdraw all shares
async function withdrawAllShares(
  kamino: Kamino,
  wallet: Keypair,
  strategyAddress: PublicKey,
  slippage: Decimal
) {
  const strategy = await kamino.getStrategyByAddress(strategyAddress);

  const withdrawIxs = await kamino.withdrawAllShares(
    strategy,
    wallet.publicKey,
    slippage
  );

  const tx = kamino.createTransactionWithExtraBudget();
  tx.add(...withdrawIxs);

  await kamino.assignBlockInfoToTransaction(tx);

  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Collect Fees & Rewards

async function collectFeesAndRewards(
  kamino: Kamino,
  wallet: Keypair,
  strategyAddress: PublicKey
) {
  const strategy = await kamino.getStrategyByAddress(strategyAddress);

  const collectIxs = await kamino.collectFeesAndRewards(
    strategy,
    wallet.publicKey
  );

  const tx = kamino.createTransactionWithExtraBudget();
  tx.add(...collectIxs);

  await kamino.assignBlockInfoToTransaction(tx);

  return await sendAndConfirmTransaction(connection, tx, [wallet]);
}

Get Pool Information

// Get supported DEXes
const dexes = kamino.getSupportedDexes();
// Returns: ["ORCA", "RAYDIUM", "METEORA"]

// Get fee tiers for DEX
const feeTiers = kamino.getFeeTiersForDex("ORCA");

// Get pools for token pair
const orcaPools = await kamino.getOrcaPoolsForTokens(tokenAMint, tokenBMint);
const raydiumPools = await kamino.getRaydiumPoolsForTokens(tokenAMint, tokenBMint);
const meteoraPools = await kamino.getMeteoraPoolsForTokens(tokenAMint, tokenBMint);

// Get current price for pair
const price = await kamino.getPriceForPair("ORCA", tokenAMint, tokenBMint);

Rebalance Methods

// Get available rebalance methods
const methods = kamino.getRebalanceMethods();
// Returns: ["MANUAL", "DRIFT", "TAKE_PROFIT", "PERIODIC", "PRICE_PERCENTAGE", ...]

// Get enabled methods
const enabledMethods = kamino.getEnabledRebalanceMethods();

// Get default method
const defaultMethod = kamino.getDefaultRebalanceMethod();

// Read rebalance parameters for strategy
const driftParams = await kamino.readDriftRebalanceParams(strategy);
const periodicParams = await kamino.readPeriodicRebalanceParams(strategy);
const priceParams = await kamino.readPricePercentageParams(strategy);

Create New Strategy

async function createStrategy(
  kamino: Kamino,
  admin: Keypair,
  params: {
    dex: "ORCA" | "RAYDIUM" | "METEORA";
    tokenAMint: PublicKey;
    tokenBMint: PublicKey;
    feeTierBps: Decimal;
    rebalanceMethod: string;
  }
) {
  const strategyKeypair = Keypair.generate();

  // Check token accounts exist
  const tokenAAccount = await kamino.getAssociatedTokenAddressAndData(
    params.tokenAMint,
    admin.publicKey
  );
  const tokenBAccount = await kamino.getAssociatedTokenAddressAndData(
    params.tokenBMint,
    admin.publicKey
  );

  // Create strategy account
  const createAccountIx = await kamino.createStrategyAccount(
    strategyKeypair.publicKey
  );

  // Initialize strategy
  const initIxs = await kamino.initializeStrategy(
    strategyKeypair.publicKey,
    admin.publicKey,
    params
  );

  const tx = kamino.createTransactionWithExtraBudget();
  tx.add(createAccountIx, ...initIxs);

  await kamino.assignBlockInfoToTransaction(tx);

  return await sendAndConfirmTransaction(
    connection,
    tx,
    [admin, strategyKeypair],
    { commitment: "finalized" }
  );
}

Scope Oracle (scope-sdk)

Oracle price aggregator providing reliable pricing data.

Initialize Scope

import { Scope } from "@kamino-finance/scope-sdk";
import { Connection, clusterApiUrl } from "@solana/web3.js";

const connection = new Connection(clusterApiUrl("mainnet-beta"));
const scope = new Scope("mainnet-beta", connection);

Get Oracle Prices

// Get all oracle prices
const prices = await scope.getOraclePrices();

// Prices indexed by token
console.log("SOL Price:", prices.get("SOL"));
console.log("USDC Price:", prices.get("USDC"));

// Get specific price
const solPrice = await scope.getPrice("SOL");
console.log("SOL/USD:", solPrice.price.toString());
console.log("Timestamp:", solPrice.timestamp);
console.log("Confidence:", solPrice.confidence);

Price Feeds

Scope aggregates from multiple oracle sources:

Pyth: Real-time market prices
Switchboard: Decentralized oracle network
TWAP: Time-weighted average prices
CLMM Prices: DEX-derived prices

// Get price with source info
const priceData = await scope.getPriceWithMetadata("SOL");
console.log("Price:", priceData.price);
console.log("Source:", priceData.source);
console.log("Age (slots):", priceData.ageSlots);

CLI Commands

Lending CLI

# Deposit tokens
yarn cli deposit --url <RPC> --owner ./keypair.json --token USDC --amount 100

# Print all lending market accounts
yarn cli print-all-lending-market-accounts --rpc <RPC>

# Print all reserve accounts
yarn cli print-all-reserve-accounts --rpc <RPC>

# Print all obligation accounts
yarn cli print-all-obligation-accounts --rpc <RPC>

# Filter with jq
yarn cli print-all-reserve-accounts --rpc <RPC> | jq '.lastUpdateSlot'
yarn cli print-all-obligation-accounts --rpc <RPC> | jq --stream 'select(.[0][1] == "owner")'

Program Addresses

Mainnet

Program	Address
Kamino Lending	`KLend2g3cP87ber41qQDzWpAFuqP2tCxDqC8S3k7L1U`
Main Market	`7u3HeHxYDLhnCoErrtycNokbQYbWGzLs6JSDqGAv5PfF`
Kamino Liquidity	`KLIQ... (varies)`
Scope Oracle	`ScopE... (varies)`

Reserve Configuration

Each reserve has configurable parameters:

interface ReserveConfig {
  // Collateral configuration
  loanToValueRatio: number;        // Max borrowing power (e.g., 0.8 = 80%)
  liquidationThreshold: number;     // Liquidation trigger (e.g., 0.85 = 85%)
  liquidationBonus: number;         // Liquidator reward (e.g., 0.05 = 5%)

  // Interest rate model
  optimalUtilizationRate: number;   // Target utilization
  borrowRateCurve: {
    baseRate: number;
    optimalRate: number;
    maxRate: number;
  };

  // Fees
  protocolTakeRate: number;         // Protocol fee on interest
  hostFeeRate: number;              // Host integration fee

  // Limits
  depositLimit: number;             // Max deposits
  borrowLimit: number;              // Max borrows

  // Status
  depositEnabled: boolean;
  borrowEnabled: boolean;
  withdrawEnabled: boolean;
}

Error Handling

import { KaminoError, ErrorCode } from "@kamino-finance/klend-sdk";

try {
  await kaminoAction.execute();
} catch (error) {
  if (error instanceof KaminoError) {
    switch (error.code) {
      case ErrorCode.InsufficientCollateral:
        console.error("Not enough collateral for this borrow");
        break;
      case ErrorCode.BorrowLimitExceeded:
        console.error("Borrow limit reached for this reserve");
        break;
      case ErrorCode.LiquidationThresholdExceeded:
        console.error("Position is at risk of liquidation");
        break;
      case ErrorCode.InvalidObligation:
        console.error("Obligation account not found or invalid");
        break;
      default:
        console.error("Kamino error:", error.message);
    }
  } else {
    throw error;
  }
}

Best Practices

Health Factor Monitoring

async function checkHealthFactor(
  market: KaminoMarket,
  wallet: PublicKey
): Promise<number> {
  await market.refreshAll();
  const obligation = await market.getUserVanillaObligation(wallet);

  if (!obligation) return Infinity;

  const stats = obligation.refreshedStats;
  const healthFactor = stats.borrowLimit / stats.borrowedValue;

  if (healthFactor < 1.1) {
    console.warn("WARNING: Health factor below 1.1, consider adding collateral");
  }

  return healthFactor;
}

Transaction Optimization

// Use lookup tables for smaller transactions
const { instructions, lookupTables } = await kaminoAction.buildWithLookupTables();

// Create versioned transaction
const messageV0 = new TransactionMessage({
  payerKey: wallet.publicKey,
  recentBlockhash: (await connection.getLatestBlockhash()).blockhash,
  instructions,
}).compileToV0Message(lookupTables);

const tx = new VersionedTransaction(messageV0);
tx.sign([wallet]);

await sendAndConfirmTransaction(connection, tx, [wallet]);

Slippage Protection

// For liquidity operations, always use slippage protection
const slippage = new Decimal(0.005); // 0.5% max slippage

const depositIxs = await kamino.deposit(
  strategy,
  wallet.publicKey,
  tokenAAmount,
  tokenBAmount,
  slippage  // Protects against price movement
);

TypeScript Types

import type {
  // Lending types
  KaminoMarket,
  KaminoAction,
  KaminoObligation,
  KaminoReserve,
  VanillaObligation,
  ReserveConfig,
  ObligationStats,

  // Liquidity types
  Kamino,
  WhirlpoolStrategy,
  StrategyWithAddress,
  ShareData,
  PositionRange,
  RebalanceMethod,
  StrategiesFilters,

  // Oracle types
  Scope,
  OraclePrices,
  PriceData,
} from "@kamino-finance/klend-sdk";

Kamino 2.0 / K-Lend (New Features)

Architecture Updates

Kamino 2.0 introduced a fully integrated application with two key layers:

Market Layer: Core lending markets with advanced risk parameters
Vault Layer: Curator-managed vault strategies for optimized yield

New Collateral Support (2025)

Asset	Type	Notes
nxSOL	LST	Nansen liquid staking token
Huma RWA	RWA	Real-world asset backed collateral
JitoSOL	LST	Jito liquid staking token

K-Lend V2 Features (Q4 2025)

Modular Lending: Isolated markets for RWAs and institutional use cases
Enhanced Risk Engine: Improved liquidation parameters
Multi-collateral Positions: Borrow against multiple assets

Governance (Q1 2026)

Decentralized decision-making via KMNO stakers will be activated, allowing token holders to vote on:

Reserve parameters
New market listings
Protocol fees

Security Milestones

Fourth protocol verification completed (October 2025)
$1.5M bug bounty program active

Resources

Skill Structure

kamino/
├── SKILL.md                        # This file
├── resources/
│   ├── klend-api-reference.md      # Complete lending API
│   ├── kliquidity-api-reference.md # Complete liquidity API
│   ├── scope-api-reference.md      # Oracle API reference
│   ├── reserve-configs.md          # Reserve configurations
│   └── program-addresses.md        # All program addresses
├── examples/
│   ├── lending/
│   │   ├── deposit-withdraw.md     # Deposit & withdraw examples
│   │   ├── borrow-repay.md         # Borrowing examples
│   │   ├── leverage.md             # Multiply/leverage examples
│   │   └── liquidation.md          # Liquidation bot example
│   ├── liquidity/
│   │   ├── strategy-management.md  # Strategy operations
│   │   ├── deposits-withdrawals.md # LP operations
│   │   └── rebalancing.md          # Rebalance strategies
│   └── oracle/
│       └── price-feeds.md          # Oracle usage examples
├── templates/
│   ├── lending-setup.ts            # Lending starter
│   ├── liquidity-setup.ts          # Liquidity starter
│   └── full-integration.ts         # Complete integration
└── docs/
    ├── troubleshooting.md          # Common issues
    └── advanced-patterns.md        # Complex patterns