Practical Implications for Developers: Key Considerations

Developers migrating from Ethereum or building new dApps on VeChainThor must consider these differences:

1. Transaction Structure:

Ethereum transactions are incompatible with VeChainThor. Developers must construct transactions using the VeChainThor format. Libraries provided in vechain-sdk-j are essential for this. Here follows the transaction body structure:

Field	Type	JSON Key	Description
ChainTag	byte	chainTag	Identifies the blockchain network the transaction is targeting.
BlockRef	string	blockRef	Reference to a specific block to maintain ordering and prevent replay attacks.
Expiration	uint32	expiration	Number of blocks until the transaction expires.
Clauses	[]*JSONClause	clauses	Array of operation clauses (each clause represents a contract call or transfer).
GasPriceCoef	uint8	gasPriceCoef	Multiplier adjusting the base gas price, affecting transaction priority.
Gas	uint64	gas	Maximum amount of gas allocated for execution.
Origin	thor.Address	origin	Address initiating the transaction.
Delegator	*thor.Address	delegator	(Optional) If present, indicates a delegator executing on behalf of origin.
Nonce	math.HexOrDecimal64	nonce	A unique number preventing transaction replay attacks.
DependsOn	*thor.Bytes32	dependsOn	(Optional) Specifies a dependency on another transaction’s hash.

1. RPC Compatibility and the SDK RPC Proxy:

The SDK RPC Proxy offers partial Ethereum JSON-RPC compatibility. Not all methods are supported, and some have different behaviors or limitations. Consult the official VeChainThor documentation for the updated list of supported methods (see Section RPC Methods).

1. Gas Calculation and VTHO:

Gas costs are paid in VTHO, not VET. Developers need to ensure their accounts have sufficient VTHO. Use VeChainThor-specific APIs to estimate VTHO costs. A feeDelegation service can be used to overcome the need, and the specific provider configuration is supported in the VeChain SDK.

1. Smart Contract Compilation:

VeChainThor supports Solidity up to the Paris EVM version.