DA

Now that you have the foundations of running and building a rollup with Rollkit, it is time to start customizing it to fit your needs.

The first choice you need to make is which data availability (DA) layer to use. The DA layer is a critical component of a blockchain, as it provides the data availability and finality guarantees that your chain needs to operate securely.

Rollkit uses the go-da interface to communicate to DA layers. Any DA layer that implements this interface can be used with Rollkit.

Go DA

The go-da interface defines the core functions required to interact with a DA layer. Probably the two most important functions being Get and Submit.

// DA defines very generic interface for interaction with Data Availability layers.
type DA interface {
	// Get returns Blob for each given ID, or an error.
	Get(ctx context.Context, ids []ID, namespace Namespace) ([]Blob, error)

	// Submit submits the Blobs to Data Availability layer.
	Submit(ctx context.Context, blobs []Blob, gasPrice float64, namespace Namespace) ([]ID, error)
}

DA layers can integrate the go-da interface directly into their node like Celestia, or they can define a middleware service like Avail.

Mock DA

You might have noticed that we did not define any DA layer during the quick start or build a chain tutorials. This is because we used a mock DA layer that is built into Rollkit.

If you revisit the logs from those tutorials, you will see one of the first lines being:

I[2024-11-15|14:09:41.735] Starting mock DA server                      module=main address=http://localhost:26658

The mock DA layer is a simple in-memory DA layer that is great for testing and development. It is not suitable for production use, as it does not provide the data availability and finality guarantees that a real DA layer would.

DA Layers

Now that you have a better understanding of what a DA layer is, you can start to explore the different DA layers that are available to use with Rollkit.

• Local DA
• Celestia DA
• Avail DA