Block Construction

Signet Block construction works very similarly to mainnet, with a few additions to help streamline the building process and correctly handle Signet Orders.

Throughout the docs we'll mention Orders. Builders should treat these as opaque extensions of the EVM. If you use official Signet rust crates and Orders will be entirely handled for you.

Overview

Building a Signet block involves the following steps:

1. Fetch transactions, bundles, and/or orders

2. Process and ingest them into the block, respecting bundle guarantees.

3. Simulate the block for validity (optional)

4. Sign the block via the Sequencer API

5. Submit it to Ethereum

Additional Builder Obligations

We expect Builders to abide by the flashbots fair market principles. Signet builders must also obey the following rule:

• Do not separate host fills from bundles. Any signed permit2 fills to be executed on Ethereum must be atomic with the block submission.

Violating market rules can result in losing the right to build Signet blocks.

Key Differences

Signet block building differs from other chains in the following ways:

• There is a hosted cache of transactions and bundles. Builders should poll the cache for transactions and bundles to simulate. See Getting Transactions and Bundles for a Block.

• Signet bundles can contain Ethereum actions, so they need special simulation. See Simulating Signet Bundles.

• Signet blocks must be co-signed by the Signet Sequencer API. See Getting a Sequencer Signature.

• Signet blocks must be submitted to Ethereum. See Submitting a block to Ethereum

Block Builder General Guidelines

• Block Builders SHOULD use a private relay like Flashbots in most cases.

• Builder slot timing processes SHOULD be handled by the Builder, typically by polling a protected endpoint until a 200 response is achieved, signifying the start of the Builder's assigned slot.