Morph Reth

Overview

Morph Reth is the next-generation execution client for Morph, a decentralized Layer 2 scaling solution for Ethereum. Built on the modular Reth SDK, it provides high-performance block execution with Morph-specific features.

Key Features

• L1 Message Support: Native handling of L1-to-L2 deposit messages with queue index validation
• Alt Fee Tokens: Support for paying transaction fees in alternative ERC-20 tokens
• Custom Receipt Types: Extended receipt format with L1 fee tracking
• Morph Hardforks: Full support for Morph's upgrade schedule (Bernoulli, Curie, Morph203, Viridian, Emerald)

Architecture

Morph Reth is designed as a modular extension of Reth, following the SDK pattern:

morph-reth/
├── crates/
│   ├── chainspec/       # Morph chain specification and hardfork definitions
│   ├── consensus/       # L2 block validation (header, body, L1 messages)
│   ├── evm/             # EVM configuration and block execution
│   ├── payload/
│   │   ├── builder/     # Block building logic
│   │   └── types/       # Engine API types (ExecutableL2Data, etc.)
│   ├── primitives/      # Core types (transactions, receipts)
│   └── revm/            # L1 fee calculation, token fee logic

Crates

Crate	Description
morph-chainspec	Chain specification with Morph hardfork timestamps
morph-consensus	Consensus validation for L2 blocks
morph-evm	EVM configuration and receipt builder
morph-payload-types	Engine API payload types
morph-payload-builder	Block building implementation
morph-primitives	Transaction and receipt types
morph-revm	L1 fee and token fee calculations

Getting Started

Prerequisites

• Rust 1.82.0 or later
• Cargo

Building from Source

git clone https://github.com/morph-l2/morph-reth.git
cd morph-reth
cargo build --release

Running Tests

# Run all tests
cargo test --all

# Run tests for a specific crate
cargo test -p morph-consensus

Development

# Format code
cargo +nightly fmt --all

# Run clippy
cargo clippy --all --all-targets -- -D warnings

# Check documentation
cargo doc --no-deps --document-private-items

Morph L2 Specifics

Transaction Types

Morph supports the following transaction types:

Type	ID	Description
Legacy	0x00	Standard legacy transactions
EIP-2930	0x01	Access list transactions
EIP-1559	0x02	Dynamic fee transactions
EIP-7702	0x04	Account abstraction transactions
L1 Message	0x7e	L1-to-L2 deposit messages
Alt Fee	0x7f	Alternative fee token transactions

L1 Messages

L1 messages are special deposit transactions that originate from Ethereum L1:

• Must appear at the beginning of each block
• Must have strictly sequential queue_index values
• Gas is prepaid on L1, so no L2 gas fee is charged
• Cannot be sent via the mempool (sequencer only)

Hardforks

Hardfork	Description
Bernoulli	Initial L2 launch
Curie	EIP-1559 fee market activation
Morph203	Various improvements
Viridian	Fee vault and alt fee support
Emerald	Block time 300ms

Development Setup

1. Fork and clone the repository
2. Create a new branch for your feature
3. Make your changes with tests
4. Ensure all checks pass: cargo fmt, cargo clippy, cargo test
5. Submit a pull request

Links

• Morph Website
• Morph Documentation
• Morph GitHub
• Reth Documentation