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: Seamless bridging of assets and messages from Ethereum L1 to Morph L2
• Morph Transaction: Versioned Morph EVM+ transaction with alternative fee-token support and Jade-era reference/memo fields
• Morph Hardforks: Implements Morph hardfork logic through Jade, with bundled Mainnet and Hoodi chainspecs currently scheduled through Emerald
• Custom Engine API: L2-specific Engine API for sequencer block building and validation
• L1 Fee Validation: Transaction pool with L1 data fee affordability checks

Supported Networks

Network	Chain ID	Type
Morph Mainnet	2818	Production
Morph Hoodi	2910	Testnet

Architecture

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

morph-reth/
├── bin/
│   └── morph-reth/      # Main CLI binary
└── crates/
    ├── chainspec/        # Morph chain specification and hardfork definitions
    ├── consensus/        # L2 block validation (header, body, L1 messages)
    ├── engine-api/       # Custom L2 Engine API (assemble/validate/import blocks)
    ├── evm/              # EVM configuration and block execution
    ├── node/             # Node assembly with component builders
    ├── payload/
    │   ├── builder/      # Block building logic
    │   └── types/        # Engine API types (MorphExecutionData, etc.)
    ├── primitives/       # Core types (transactions, receipts)
    ├── revm/             # L1 fee calculation, token fee logic
    ├── rpc/              # RPC implementation and type conversions
    └── txpool/           # Transaction pool with L1 fee validation

Crates

Crate	Description
morph-reth	Main CLI binary — Morph L2 Execution Layer Client
morph-chainspec	Chain specification with Morph hardfork definitions
morph-consensus	Consensus validation for L2 blocks
morph-engine-api	Custom L2 Engine API for sequencer interaction
morph-evm	EVM configuration and receipt builder
morph-node	Node implementation with modular component builders
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
morph-rpc	RPC implementation and type conversions
morph-txpool	Transaction pool with L1 fee and MorphTx validation

Getting Started

Prerequisites

• Rust 1.88 or later
• Cargo

Building from Source

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

Running the Node

Morph Reth is a sequencer-driven L2 execution client. Block production and import are driven through the custom L2 Engine API by an external sequencer or derivation pipeline, and the execution layer must stay aligned with the Morph consensus node state.

# Generate a JWT secret for Engine API authentication
openssl rand -hex 32 > jwt.hex

# Run on Morph mainnet
./target/release/morph-reth node \
  --chain mainnet \
  --http \
  --authrpc.jwtsecret jwt.hex

# Run on Hoodi testnet
./target/release/morph-reth node \
  --chain hoodi \
  --http \
  --authrpc.jwtsecret jwt.hex

# Run with a custom genesis file
./target/release/morph-reth node \
  --chain /path/to/genesis.json \
  --http \
  --authrpc.jwtsecret jwt.hex

Note: The commands above only start the Morph execution client. In production, bootstrap with a paired reth + node snapshot at the same height, because Morph EL state must stay aligned with the consensus node's node-data. The node still requires a sequencer or derivation pipeline to drive the custom Engine API (engine_assembleL2Block, engine_newL2Block, etc.) for block production and import. See Morph Documentation for deployment guides.

Morph-Specific CLI Flags

Flag	Default	Description
--morph.max-tx-payload-bytes	122880 (120KB)	Maximum transaction payload bytes per block
--morph.max-tx-per-block	None (unlimited)	Maximum number of transactions per block

Running Tests

# Run all tests
cargo test --all

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

Development

# Format code
cargo fmt --all

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

# Run doc tests
cargo test --doc --all --verbose

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	Delegate EOA execution to smart contract code
L1 Message	0x7e	L1-to-L2 deposit messages
Morph Transaction	0x7f	Morph EVM+ transaction with enhanced features

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)

Morph Transaction

Morph Transaction (0x7f) is a versioned custom transaction type that extends EIP-1559-style transactions with alternative fee payment and, from Jade onward, optional metadata fields:

Version	Availability	Description
V0	Always	Requires fee_token_id > 0, uses an active fee token from the L2 Token Registry, and does not support reference or memo
V1	Jade+	Adds optional reference (32 bytes) and memo (max 64 bytes); fee_token_id == 0 uses the normal ETH-fee path, while fee_token_id > 0 uses an active registry token

Hardforks

Bernoulli and Curie use block-based activation; Morph203, Viridian, Emerald, and Jade use timestamp-based activation.

The codebase implements hardfork logic through Jade, but the bundled Mainnet and Hoodi chainspecs currently schedule through Emerald.

Hardfork	Activation	Description
Bernoulli	Block	Initial L2 launch with disabled ripemd160 and blake2f precompiles
Curie	Block	Introduces blob-based L1 data-fee calculation and initializes the Curie L1 Gas Price Oracle fields
Morph203	Timestamp	Re-enable ripemd160 and blake2f precompiles
Viridian	Timestamp	EIP-7702 EOA delegation support
Emerald	Timestamp	BLS12-381 and P256verify precompiles
Jade	Timestamp	MPT state root validation, MorphTx V1 with reference and memo fields

Before Jade, Morph uses ZK-trie state roots, so morph-reth intentionally skips state-root equality checks and only enables MPT state-root validation at Jade.

Engine API

Morph provides a custom L2 Engine API (different from the standard Ethereum Engine API) for sequencer interaction:

Method	Description
engine_assembleL2Block	Build executable L2 block data for the next height; the sequencer supplies L1-message transactions via the transactions parameter, and L2 transactions are pulled from the txpool
engine_validateL2Block	Validate executable block data without importing it
engine_newL2Block	Import a new L2 block via newPayload + forkchoiceUpdated and advance the canonical head
engine_newSafeL2Block	Rebuild and import a safe L2 block from derivation inputs
engine_setBlockTags	Update safe/finalized block tags without importing a block

Contributing

See CONTRIBUTING.md for guidelines on how to contribute.

License

Licensed under either of:

• Apache License, Version 2.0
• MIT License

at your option.

Links

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