shard-sdk: minimal rollup framework

shard-sdk is a CLI tool designed to streamline the creation of simple based rollups on Celestia using a minimal template.

There is no bloat.

There are no features.

Because of the architectural simplicity of based rollups, all you need to implement is the verification and processing of transactions, as well as state management.

Examples here

Installation

We use just as a task runner. After cloning the repo, run the following command to install the binary.

just install

Usage

Create a new project

shard init [rollup-name]

If no project name is provided, the default project name is “my-rollup”.

Adding a new TransactionType

This will create a new transaction type with the specified fields and prepares both the transaction and state handling code automatically. Make sure you are in the rollup directory before you’re using shard create-tx ...

shard create-tx <tx-name> [field_name field_type]...

For example:

shard create-tx SendMessage msg String user String

After creating a new transaction type, you'll need to:

1. Update the verify() method in src/tx.rs to add your custom validation logic
2. Modify the process() method to implement the transaction logic

Running the rollup

To start a local celestia network, run

just celestia-up

Starting the node

After installing the binary for your rollup, you can run

my-rollup-name serve

Creating a signer

If you have enabled signature verification, you will need to use signers. Generating signers to use with your rollup is easy:

my-rollup-name create-signer user1

Submitting transcations

Let's say you used the SendMessage transaction type example above. To send a transaction, you can run:

my-rollup-name submit-tx send-message --key-name user1 --nonce 0 "Here is my message!" "Ryan"

You can omit the --key-name if signature verification is disabled, and --nonce if you haven't implemented nonce controls.

Notes

Signature verification is disabled by default to allow for quick experimentation.

To enable it, change SIGNATURE_VERIFICATION_ENABLED in your-rollup/src/tx.rs to true .

Nonce control is also not implemented by default. To prevent replay attacks, ensure processed transactions increment an account nonce. See example here [COMING SOON].

Roadmap:

• Implement State as trait to not need to copy syncing logic
• Provide hooks for block processing, e.g. OnRecvCelestiaBlock(ExtendedHeader)
• Improve UX for adding webserver endpoints, provide examples
• Provide examples for nonce control
• ZK template with sp1
• Integrate prism sdk
• Fully move to lumina once ready
• Ship with an in browser light node for zk template