HyperEVM Dual Block Architecture

What is Dual Block Architecture?

HyperEVM has a unique architecture using two block types: Small Block and Big Block.

Traditional blockchains had to choose between block speed and block size:

• Fast blocks: Transactions confirm quickly, but small block size limits complex operations
• Large blocks: Complex contract deployments possible, but slower block creation degrades user experience

HyperEVM's dual block architecture is designed to get the best of both worlds. Regular transactions confirm quickly, while complex operations are handled reliably in big blocks.

Two Block Types

Small Block

Block creation time: 1 second
Gas limit: 2,000,000 (per documentation)
Actual gas limit: 3,000,000 (verified via block explorer)

Main Use Cases

• Regular token transfers
• Simple smart contract calls
• Time-sensitive transactions
• DeFi operations like DEX swaps or lending/repayment

Features

• Blocks created every second for fast finality
• Improved user experience (quick transaction confirmation)
• Sufficient gas for most everyday operations

Real Example: Block #20,040,192

Big Block

Block creation time: 60 seconds
Gas limit: 30,000,000

Main Use Cases

• Smart contract deployment
• Complex initialization operations
• Batch operations processing large amounts of data
• Complex computations requiring high gas

Features

• 10x larger gas limit (3M → 30M)
• Deploy complex contracts in a single transaction
• Increased efficiency by batch processing multiple operations

Real Example: Block #20,040,172

Block Type Comparison

Technical Structure

On-Chain Mempool Separation

HyperEVM's mempool is managed as on-chain state at the L1 execution level and is separated into two independent mempools for the dual block system:

• Small Block mempool: Queue for small transactions
• Big Block mempool: Queue for large transactions

Each mempool only allows the next 8 nonces per address. Transactions older than 1 day are automatically removed.

Block Numbering

Both block types are interleaved and have unique increasing EVM block numbers.

Big Block Creation Rules

Official documentation:

"block duration of x means that the first L1 block for each value of l1_block_time % x produces an EVM block"

Analyzing actual blocks shows that Big Blocks are created when Block Number % 61 = 25.

Block Number % 61 = 25  → Big Block (30M gas)
Block Number % 61 ≠ 25 → Small Block (3M gas)

Actual Block Verification:

Big Blocks (all % 61 = 25):

• #20,039,745, #20,039,867, #20,040,111, #20,040,172

Small Blocks (all % 61 ≠ 25):

• #20,040,185, #20,040,192, #20,040,200

Pattern: A Big Block repeats every 61 blocks (60 Small Blocks + 1 Big Block).

Using Big Blocks

Large transactions like contract deployments should use Big Blocks.

{
  "type": "evmUserModify",
  "usingBigBlocks": true
}

Sending this action routes your transaction to a Big Block. You can test at hyperevm-block-toggle.vercel.app (unofficial).

After your operation is complete, revert to "usingBigBlocks": false.