Differences from Ethereum

Immutable Chain is built from a geth fork and maintains high compatibility with Ethereum. However, there are some notable differences developers should be aware of.

Source Code

View the Immutable geth fork on GitHub

Solidity Compatibility

Immutable Chain’s most recent hard fork aligns with Ethereum’s Cancun fork. We officially support Solidity versions up to and including 0.8.28.

// Recommended pragma
pragma solidity >=0.8.19 <0.8.29;

If you use ^0.8.19, you may pull a compiler version not compatible with Immutable Chain. Always pin your version.

EVM Differences

EIP-4844 Blobs

Blob transactions are not supported. Any such transactions will be rejected by the RPC.

Op Code	Behavior
`BLOBHASH`	Returns empty `bytes32` (0x0)
`BLOBBASEFEE`	Returns 0x1

Block headers blobGasUsed and excessBlobGas are always 0x0.

PREVRANDAO Op Code

The PREVRANDAO op code (EIP-4399) always returns uint256(0) on Immutable Chain.

Do not rely on PREVRANDAO for randomness. Use an oracle like Supra VRF instead.

RPC Endpoint Differences

Some RPC methods are disabled for security and performance:

Category	Methods	Reason
Debug	`debug_*`	Unbounded memory usage, DDoS risk
Engine	`engine_*`	Not needed for external use
Txpool	`txpool_*`	Prevents front-running
Admin	`admin_*`	Internal operations only

For debug methods, use QuickNode which provides dedicated endpoints. See Ecosystem Partners.

Gas Pricing

Immutable Chain uses EIP-1559 gas pricing. See the full gas configuration:

Property	Value
Gas Model	EIP-1559
Min Priority Fee	10 gwei
Block Gas Limit	30,000,000
Gas Sponsorship	Available for Passport users

// Always set minimum priority fee
const tx = await contract.method({
  maxPriorityFeePerGas: 10_000_000_000n, // 10 gwei
  maxFeePerGas: 15_000_000_000n,
});

See Gas Sponsorship for sponsored transactions.

Resources

Chain Configuration

Network details and RPC endpoints

Bridging

Core protocol addresses

Next Steps

Deploy Contracts

Deploy contracts with Hardhat

Chain Overview

Network configuration details

Gas Sponsorship

Sponsor user transactions

Ecosystem Partners

Find RPC and development tools

PRODUCTS

GUIDES

Differences from Ethereum

Source Code

Solidity Compatibility

EVM Differences

EIP-4844 Blobs

PREVRANDAO Op Code

RPC Endpoint Differences

Gas Pricing

Resources

Chain Configuration

Bridging

Next Steps

Deploy Contracts

Chain Overview

Gas Sponsorship

Ecosystem Partners

Source Code

​Solidity Compatibility

​EVM Differences

​EIP-4844 Blobs

​PREVRANDAO Op Code

​RPC Endpoint Differences

​Gas Pricing

​Resources

Chain Configuration

Bridging

​Next Steps

Deploy Contracts

Chain Overview

Gas Sponsorship

Ecosystem Partners

Solidity Compatibility

EVM Differences

EIP-4844 Blobs

PREVRANDAO Op Code

RPC Endpoint Differences

Gas Pricing

Resources

Next Steps