Interactive Contract Playground

Test LayerZero contracts directly from your browser. No coding required. Explore key application functions for message fee calculation, sending, receiving, configuration, and state management. This page focuses on methods relevant to building applications and does not include worker-related functions.

​

LayerZero EndpointV2

The main entry point for all crosschain messaging operations. This contract handles message routing, fee calculation, and configuration management.

​

Message Routing

Core functions for sending and receiving messages between smart contracts.

​

quote() - Get Fee Estimates

​

send() - Send Messages

​

lzReceive() - Receive Messages

​

sendCompose() - Send Compose Messages

​

lzCompose() - Execute Compose Messages

​

Configuration Management

Functions for setting custom verification, execution, and pathway management.

​

eid() - Get Endpoint ID

​

isRegisteredLibrary() - Check Library Registration

​

receiveLibraryTimeout() - Get Library Timeout

​

setDelegate() - Set Delegate Address

​

setSendLibrary() - Configure Send Library

​

setReceiveLibrary() - Configure Receive Library

​

setConfig() - Set Configuration Parameters

​

Message Recovery & Security

Functions for handling message exceptions, security threats, and recovery scenarios.

​

clear() - Clear Stored Message

​

burn() - Permanently Block Message

​

skip() - Skip Message Nonce

​

nilify() - Mark Message as Nil

​

Status Checks

Functions for querying current configuration settings, library assignments, nonce tracking, and message states.

​

getConfig() - Check Configuration

​

delegates() - Check Delegate Address

​

getSendLibrary() - Get Send Library

​

getReceiveLibrary() - Get Receive Library

​

inboundNonce() - Get Processed Nonce

​

lazyInboundNonce() - Get Lazy Nonce

​

initializable() - Check Message Initialization

​

verifiable() - Check Message Verification

​

inboundPayloadHash() - Get Message Payload Hash

​

nextGuid() - Get Next Message GUID

​

composeQueue() - Check Compose Message Queue

​

isSendingMessage() - Check Send State

​

getSendContext() - Get Current Send Context

​

Events

Key events emitted by the EndpointV2 contract.

​

PacketSent - Message Sent Event

​

PacketVerified - Message Verified Event

​

PacketDelivered - Message Delivered Event

​

ComposeSent - Compose Message Queued Event

​

ComposeDelivered - Compose Message Delivered Event

​

DelegateSet - Delegate Configuration Event

​

SendLibrarySet - Send Library Configuration Event

​

ReceiveLibrarySet - Receive Library Configuration Event

​

ReceiveLibraryTimeoutSet - Library Timeout Configuration Event

​

InboundNonceSkipped - Nonce Skip Event

​

PacketNilified - Message Nilified Event

​

PacketBurnt - Message Burnt Event

​

Errors

​

LZ_InsufficientFee - Insufficient Fee

​

LZ_InvalidNonce - Invalid Nonce

​

LZ_Unauthorized - Unauthorized Access

​

LZ_SendReentrancy - Send Reentrancy Detected

​

Key Functions to Try:

• Messaging Operations:
  • quote() - Get fee estimates for crosschain messages
  • send() - Send messages to other chains
  • lzReceive() - Receive messages from other chains
  • sendCompose() - Queue compose messages
  • lzCompose() - Execute compose messages
• Configuration Management:
  • setDelegate() - Assign configuration permissions
  • setSendLibrary() - Choose send message library
  • setReceiveLibrary() - Choose receive message library
  • setConfig() - Set library-specific parameters
• Message Recovery & Security:
  • burn() - Permanently block malicious messages
  • skip() - Skip flagged message nonces
  • nilify() - Mark messages for re-verification
  • clear() - Clear verified but unexecuted messages
• Status Checks:
  • getConfig() - Check current configurations
  • delegates() - View current delegate address
  • getSendLibrary() - Check send library for endpoint
  • getReceiveLibrary() - Check receive library for endpoint
  • inboundNonce() - Get highest processed message nonce
  • lazyInboundNonce() - Get highest verified/skipped nonce
  • nextGuid() - Get next message GUID
  • composeQueue() - Check compose queue
  • isSendingMessage() - Check send state
  • getSendContext() - Get send context

​

LayerZero Message Libraries

Message Libraries handle the core verification and execution logic for LayerZero messages. While developers don’t interact with these contracts directly, understanding their error codes and events is crucial for debugging failed transactions.

​

Current Message Libraries

• SendUln302: Handles outbound message verification setup
• ReceiveUln302: Processes inbound message verification and execution
• ReadLib1002: Manages crosschain read operations

When You’ll See These: These errors appear when calling Endpoint methods like send() or lzReceive(). The Endpoint delegates to these libraries internally, so their errors bubble up through your Endpoint transactions.

​

SendUln302 - Outbound Message Library

The SendUln302 library manages the configuration and verification setup for outbound messages. It coordinates with DVNs (Decentralized Verifier Networks) and handles fee calculations for message transmission.

​

Errors

Configuration & Setup Errors

​

LZ_ULN_InvalidConfigType - Invalid Configuration Type

​

LZ_ULN_InvalidRequiredDVNCount - Invalid DVN Count

​

LZ_ULN_InvalidOptionalDVNCount - Invalid Optional DVN Count

​

LZ_ULN_InvalidOptionalDVNThreshold - Invalid DVN Threshold

​

LZ_ULN_AtLeastOneDVN - At Least One DVN Required

​

LZ_ULN_InvalidConfirmations - Invalid Confirmations

​

LZ_ULN_Unsorted - DVNs Not Sorted

Worker & Option Errors

​

LZ_ULN_InvalidWorkerId - Invalid Worker ID

​

LZ_ULN_InvalidWorkerOptions - Invalid Worker Options

​

LZ_ULN_UnsupportedOptionType - Unsupported Option Type

​

LZ_ULN_InvalidLegacyType1Option - Invalid Legacy Type 1 Option

​

LZ_ULN_InvalidLegacyType2Option - Invalid Legacy Type 2 Option

​

LZ_ULN_UnsupportedEid - Unsupported Endpoint ID

Fee & Payment Errors

​

LZ_MessageLib_InvalidAmount - Invalid Fee Amount

​

LZ_MessageLib_TransferFailed - Fee Transfer Failed

Library Access Errors

​

LZ_MessageLib_OnlyEndpoint - Only Endpoint Allowed

​

LZ_MessageLib_InvalidExecutor - Invalid Executor

​

LZ_MessageLib_NotTreasury - Not Treasury

​

LZ_MessageLib_CannotWithdrawAltToken - Cannot Withdraw Alt Token

Message Validation Errors

​

LZ_MessageLib_InvalidMessageSize - Message Too Large

​

LZ_MessageLib_ZeroMessageSize - Zero Message Size

​

DVN_InvalidDVNOptions - Invalid DVN Options

​

DVN_InvalidDVNIdx - Invalid DVN Index

Transfer Errors

​

Transfer_NativeFailed - Native Transfer Failed

​

Transfer_ToAddressIsZero - Transfer to Zero Address

​

Events

​

DVNFeePaid - DVN Fee Payment

​

ReceiveUln302 - Inbound Message Library

The ReceiveUln302 library handles the verification and execution of inbound messages. It validates DVN signatures, manages message ordering, and ensures secure message delivery.

​

Errors

Verification Errors

​

LZ_ULN_InvalidPacketHeader - Invalid Packet Header

​

LZ_ULN_InvalidPacketVersion - Wrong Packet Version

​

LZ_ULN_InvalidEid - Invalid Endpoint ID

Configuration Errors

​

LZ_ULN_InvalidConfigType - Invalid Configuration Type

​

LZ_ULN_InvalidRequiredDVNCount - Invalid DVN Count

​

LZ_ULN_InvalidOptionalDVNCount - Invalid Optional DVN Count

​

LZ_ULN_InvalidOptionalDVNThreshold - Invalid DVN Threshold

​

LZ_ULN_AtLeastOneDVN - At Least One DVN Required

​

LZ_ULN_InvalidConfirmations - Invalid Confirmations

​

LZ_ULN_Unsorted - DVNs Not Sorted

​

LZ_ULN_UnsupportedEid - Unsupported Endpoint ID

​

LZ_ULN_Verifying - Already Verifying

​

LZ_MessageLib_OnlyEndpoint - Only Endpoint Allowed

​

ReadLib1002 - Crosschain Read Library

The ReadLib1002 library enables crosschain data reading without state changes. It manages read channels, handles request/response cycles, and ensures data integrity.

​

Errors

Configuration Errors

​

LZ_RL_InvalidConfigType - Invalid Configuration Type

​

LZ_RL_InvalidRequiredDVNCount - Invalid DVN Count

​

LZ_RL_InvalidOptionalDVNCount - Invalid Optional DVN Count

​

LZ_RL_InvalidOptionalDVNThreshold - Invalid DVN Threshold

Validation Errors

​

LZ_RL_InvalidPacketHeader - Invalid Packet Header

​

LZ_RL_InvalidPacketVersion - Wrong Packet Version

​

LZ_RL_InvalidCmdHash - Invalid Command Hash

​

LZ_RL_InvalidReceiver - Invalid Receiver

​

LZ_RL_InvalidAmount - Invalid Fee Amount

​

LZ_RL_Verifying - Already Verifying

​

LZ_RL_InvalidEid - Invalid Endpoint ID

​

LZ_RL_AtLeastOneDVN - At Least One DVN Required

​

LZ_RL_Unsorted - DVNs Not Sorted

​

LZ_RL_UnsupportedEid - Unsupported Endpoint ID

Library Access Errors

​

LZ_MessageLib_OnlyEndpoint - Only Endpoint Allowed

​

LZ_RL_InvalidExecutor - Invalid Executor

​

LZ_RL_NotTreasury - Not Treasury

​

LZ_RL_CannotWithdrawAltToken - Cannot Withdraw Alt Token

Worker & Option Errors

​

LZ_ULN_InvalidWorkerId - Invalid Worker ID

​

LZ_ULN_InvalidWorkerOptions - Invalid Worker Options

​

LZ_ULN_UnsupportedOptionType - Unsupported Option Type

​

LZ_ULN_InvalidLegacyType1Option - Invalid Legacy Type 1 Option

​

LZ_ULN_InvalidLegacyType2Option - Invalid Legacy Type 2 Option

DVN Errors

​

DVN_InvalidDVNOptions - Invalid DVN Options

​

DVN_InvalidDVNIdx - Invalid DVN Index

Transfer Errors

​

Transfer_NativeFailed - Native Transfer Failed

​

Transfer_ToAddressIsZero - Transfer to Zero Address

​

Troubleshooting Common Library Errors

​

Fee-Related Issues

• LZ_MessageLib_InvalidAmount: Always use quote() before send() to get exact fees
• LZ_MessageLib_TransferFailed: Ensure contract has sufficient ETH balance
• LZ_RL_InvalidAmount: Ensure correct fee for read operations
• DVN_InvalidDVNOptions: Check DVN option encoding and parameters

​

Configuration Issues

• LZ_ULN_InvalidRequiredDVNCount: Must have at least 1 required DVN
• LZ_ULN_InvalidOptionalDVNThreshold: Threshold must be ≤ optional DVN count
• LZ_ULN_InvalidConfigType: Use correct config type (ULN=2, Executor=1)
• LZ_RL_InvalidConfigType: Use correct config type for read library

​

Verification Issues

• LZ_ULN_Verifying: Message already being verified, wait for completion
• LZ_RL_Verifying: Read response already being verified
• LZ_ULN_InvalidPacketHeader: Possible message corruption or tampering
• LZ_RL_InvalidPacketHeader: Read packet header malformed
• LZ_ULN_InvalidPacketVersion: Wrong packet version for message library
• LZ_RL_InvalidPacketVersion: Wrong packet version for read library

For detailed troubleshooting guides, see LayerZero Troubleshooting.

​

Omnichain Application (OApp)

The foundation for building any crosschain application. OApp provides the core messaging infrastructure for a smart contract interacting with the EndpointV2.

​

Core Information

​

oAppVersion() - Get OApp Version

​

endpoint() - Get Endpoint Address

​

Peer Configuration

​

peers() - Get Remote Peer Address

​

setPeer() - Connect Remote Chains

​

setDelegate() - Set Configuration Delegate

​

Message Reception

​

allowInitializePath() - Check Path Initialization

​

nextNonce() - Get Next Message Nonce

​

lzReceive() - Receive Crosschain Messages

​

Composability

​

isComposeMsgSender() - Verify Compose Sender

​

Events and Errors

Key events and errors emitted by the OApp contract.

​

Events

​

PeerSet - Peer Configuration Updated

​

Errors

​

OnlyPeer - Unauthorized Peer Message

​

NoPeer - Missing Peer Configuration

​

InvalidEndpointCall - Invalid Endpoint Call

​

InvalidDelegate - Invalid Delegate Configuration

​

NotEnoughNative - Insufficient Native Fee

​

OnlyEndpoint - Unauthorized Endpoint Call

​

LzTokenUnavailable - LayerZero Token Not Available

​

Key Functions to Try:

• Core Information:
  • oAppVersion() - Get OApp version information
  • endpoint() - Get connected endpoint address
• Peer Configuration:
  • setPeer() - Connect to remote chains
  • peers() - Check connected chains
  • setDelegate() - Set configuration delegate
• Message Reception:
  • lzReceive() - Receive crosschain messages
  • allowInitializePath() - Check path initialization
  • nextNonce() - Get message ordering info
• Composability:
  • isComposeMsgSender() - Verify compose sender

​

Tips:

• Peers must be set before messaging
• Nonces ensure ordered delivery
• Options control execution parameters

​

Omnichain Application Read (OAppRead)

OAppRead extends the standard OApp with LayerZero Read functionality, enabling crosschain data reading capabilities. It includes all standard methods plus the read channel configuration.

​

setReadChannel() - Configure Read Channel

​

Key Functions to Try:

• setReadChannel() - Configure read channel for crosschain data reading
• Plus all standard OApp functions listed above

​

Omnichain Fungible Token (OFT)

OFT inherits from OApp, providing all crosschain messaging capabilities plus token-specific functionality. Create tokens that work seamlessly across multiple blockchains while maintaining a unified supply.

​

Send Tokens

​

quoteSend() - Get Transfer Fees

​

quoteOFT() - Get Detailed Transfer Quote

​

send() - Transfer Tokens

​

Token Details

​

sharedDecimals() - Get Shared Decimals

​

approvalRequired() - Check Approval Requirement

​

oftVersion() - Get OFT Version

​

token() - Get Underlying Token Address

​

decimalConversionRate() - Get Decimal Conversion Factor

​

Management Functions

​

owner() - Get Current Owner

​

transferOwnership() - Transfer Contract Ownership

​

renounceOwnership() - Renounce Ownership

​

setPeer() - Connect to Remote OFTs

​

setEnforcedOptions() - Configure Message Options

​

setMsgInspector() - Set Message Inspector

​

Events

Key events emitted by the OFT contract.

​

OFTSent - Token Transfer Sent

​

OFTReceived - Token Transfer Received

​

Transfer - Standard ERC20 Transfer

​

Errors

​

InvalidLocalDecimals - Invalid Decimal Configuration

​

SlippageExceeded - Transfer Slippage Too High

​

AmountSDOverflowed - Shared Decimal Overflow

​

Key Functions to Try:

• Transfer Operations:
  • quoteSend() - Get transfer fee estimates
  • send() - Transfer tokens crosschain
  • quoteOFT() - Get comprehensive transfer quotes
• Token Information:
  • sharedDecimals() - Check decimal configuration
  • approvalRequired() - Check if approval is needed
  • oftVersion() - Get OFT implementation version
  • token() - Get underlying token address
  • decimalConversionRate() - Get decimal conversion factor
• Management Functions:
  • owner() - Check current contract owner
  • setPeer() - Connect to OFTs on other chains
  • setEnforcedOptions() - Configure security parameters
  • setMsgInspector() - Set message inspector
  • transferOwnership() - Transfer contract ownership
  • renounceOwnership() - Permanently remove ownership

​

Tips:

• Always call quoteSend() before send() to get accurate fees
• The minAmountLD parameter provides slippage protection
• Shared decimals (typically 6-8) may differ from local decimals (e.g., 18 for most ERC20s)
• approvalRequired() returns false for OFT and true for OFTAdapter
• Use quoteOFT() for detailed information including transfer limits and fee breakdowns
• OFTAdapter requires approval on the underlying token before sending
• Must call setPeer() to connect OFTs on different chains before transfers
• Only the contract owner can call management functions
• Use setEnforcedOptions() to enforce minimum gas limits for security
• renounceOwnership() is irreversible - use with extreme caution

For complete contract documentation including all functions, events, and technical details:

• Contract Standards Overview
• OApp Technical Reference
• OFT Technical Reference
• Protocol Contracts

​

Decentralized Verifier Network (DVN)

DVNs provide independent verification of crosschain messages. Each DVN can set custom pricing and confirmation requirements for different destination chains.

​

getFee() - Get DVN Verification Fee

InteractiveDVN temporarily disabled.

​

dstConfig() - Get DVN Configuration

InteractiveDVN temporarily disabled.

​

Executor

Executors handle the final delivery of verified messages on destination chains. They manage gas pricing, execution parameters, and delivery guarantees.

​

getFee() - Get Execution Fee

​

dstConfig() - Get Destination Configuration