Contract Limits

MegaETH contract size limits — 512 KB max bytecode, 536 KB max initcode, inherited from MiniRex.

This page specifies MegaETH's limits on deployed contract bytecode size and initcode size. It defines the contract-size limits inherited from MiniRex.

Motivation

Contract size and initcode size directly affect execution cost, state footprint, and validation overhead. MegaETH raises these limits to accommodate larger deployments, but the protocol must still define explicit maximum values so all nodes reject oversized contracts consistently.

Specification

A node MUST enforce the following limits:

Limit	Value
Maximum deployed contract size	MAX_CONTRACT_SIZE
Maximum initcode size	MAX_INITCODE_SIZE

If deployed runtime bytecode exceeds MAX_CONTRACT_SIZE, the node MUST reject the deployment. If initcode exceeds MAX_INITCODE_SIZE, the node MUST reject the creation transaction or creation opcode execution.

The initcode limit is defined as:

MAX_INITCODE_SIZE = MAX_CONTRACT_SIZE + ADDITIONAL_INITCODE_SIZE

Zero-Length Init Code in CREATE2

When a CREATE2 opcode is executed with an init-code length of zero, a node MUST short-circuit after validating the salt operand: it MUST use the keccak-256 hash of the empty byte string as the resulting init-code hash, and MUST NOT perform any offset conversion, memory expansion, or hashing of memory. Because the init-code length is zero, the init-code offset operand MUST be ignored entirely, even when it is a very large value. This ensures that a zero-length CREATE2 charges no memory-expansion gas (and no associated compute gas) for the unused offset operand and never halts with a spurious out-of-gas error caused by an out-of-range offset whose length is zero.

Constants

Constant	Value	Description
MAX_CONTRACT_SIZE	524,288 bytes	Maximum size of deployed contract bytecode
ADDITIONAL_INITCODE_SIZE	24,576 bytes	Additional bytes allowed above the contract-size limit for initcode
MAX_INITCODE_SIZE	548,864 bytes	Maximum initcode size

Rationale

Why raise the contract limits? MegaETH allows substantially larger contracts than standard Ethereum. The enlarged limits support deployment patterns that would otherwise exceed Ethereum's contract-size constraints.

Security Considerations

This page has no security considerations.

Spec History

• MiniRex introduced the enlarged contract and initcode limits.
• Rex, Rex1, Rex2, Rex3, and Rex4 retain the same stable limits.
• Rex5 short-circuits zero-length CREATE2 after salt validation, using the empty-init-code hash without observing the init-code offset operand.