CCIP v2.0.0 LockReleaseTokenPool API Reference

LockReleaseTokenPool is a TokenPool implementation that locks tokens on the source chain and releases escrowed tokens on the destination chain.

If you use this pool, tokens are transferred into a lockbox on the source chain and released from escrow on the destination chain.

This approach preserves total token supply and relies on custody and available liquidity rather than mint/burn mechanics.

Use this variant when bridging tokens without modifying total supply (lock-and-release model), rather than burning and minting tokens.

This contract is not intended to be called directly by applications. It is used by CCIP infrastructure during token transfers.

Usage Boundary

You do not call this contract directly.

• The Router and OnRamp/OffRamp contracts invoke this pool during cross-chain token transfers.
• You choose this pool when configuring how a token is bridged across chains.
• Use this pool when you want to preserve total token supply across chains.
• You are responsible for ensuring the lockbox securely holds and releases tokens.
• If the lockbox does not hold sufficient tokens to satisfy a release, the transfer will fail.

Contract

pools/LockReleaseTokenPool.sol

Import

import {LockReleaseTokenPool} from "chainlink-ccip/pools/LockReleaseTokenPool.sol";

If you have not installed the package:

npm install @chainlink/contracts-ccip@2.0.0

Inheritance

• TokenPool
• ITypeAndVersion

Constructor

constructor(
  IERC20 token,
  uint8 localTokenDecimals,
  address advancedPoolHooks,
  address rmnProxy,
  address router,
  address lockBox
) TokenPool(
  token,
  localTokenDecimals,
  advancedPoolHooks,
  rmnProxy,
  router
)

External API

getLockBox

function getLockBox() external view returns (address)

Returns the configured lockbox address.

Returns:

typeAndVersion

function typeAndVersion() external pure virtual override returns (string memory)

Returns:

Events

No new events declared.

For a cross-contract event index, see Events.

Errors

No new custom errors declared.

For a cross-contract error index, see Errors.

Internal Functions

_lockOrBurn

function _lockOrBurn(
  uint64 remoteChainSelector,
  uint256 amount
) internal override

Locks tokens by transferring them into the configured lockbox.

• Tokens are transferred from the sender into escrow in the lockbox.
• The lockbox holds tokens until they are released on the destination chain.

_releaseOrMint

function _releaseOrMint(
  address receiver,
  uint256 amount,
  uint64 remoteChainSelector
) internal override

Transfers tokens from the lockbox to the receiver.

• The lockbox must hold sufficient tokens to fulfill the release.
• No minting occurs; tokens must already exist in escrow.

Security model

• The lockbox is the sole custody layer for escrowed tokens.
• All token accounting depends on the correctness of the lockbox.
• Only authorized CCIP components (OnRamp and OffRamp) can trigger token movements.
• If the lockbox is compromised or misconfigured, escrowed tokens may be lost or stolen.

Notes

• This pool does not change token supply; tokens are locked and later released.
• This model depends on both secure custody and sufficient escrowed liquidity.
• Each locked token on the source chain must correspond to an available token in the destination lockbox.
• The lockbox must be pre-funded with sufficient liquidity to support incoming transfers.
• Tokens must be available in the lockbox to fulfill release operations.
• Unlike burn/mint pools, this model requires maintaining liquidity in the lockbox.
• Unlike burn/mint models, token availability is constrained by lockbox liquidity rather than total supply.
• If maintaining escrowed liquidity is not feasible, use a burn/mint pool instead.
• Pool configuration and lockbox selection are fixed at deployment. Changing them requires deploying a new pool.

Related Interfaces & Contracts

• ILockBox
• TokenPool
• BurnMintTokenPool
• RateLimiter
• TokenAdminRegistry
• Router