Rollups as a service (RAAS)

What is RAAS?

Rollups as a service (RAAS) is a scaling service offered by Ankr to large and small businesses.

RAAS allows you to have a turnkey scaling solution easily implemented into your business processes. The great reputation of the leading Web3 infrastructure company guarantees that quality and involvement of Ankr engineers collecting initial parameters, setting a RAAS up, and supporting streamlining it into your company's daily routine.

What are rollups?

Rollups are a Layer 2 scaling solution that increases transaction output by bundling multiple transactions into batches, which are processed off-chain. After that, the transaction data is recorded on the main chain with data compression techniques that help lower cost and increase speed. Assets are always held in an on-chain smart contract.

This approach reduces congestion and computation load on the base or main blockchain, thereby increasing transaction throughput.

The first reason for the growing adoption of rollups is the increasing popularity of crypto and blockchain, which has lead to many popular blockchains meeting their speed limits. The rising crypto demand could lead to network congestion and expensive transaction costs. To address this, scaling solutions are being developed and tested, among them, rollups.

The second reason for their adoption is the use cases of many legal and baning companies that require privacy due to various business and legal reasons. An example can be a bank that wants to be ready and compliant for ledger audits, but doesn't want to reveal any sensitive information, such as the parties involved in the banking transactions.

Types of rollups

There are two main types of rollups:

• Optimistic rollups — rollups that assume transactions are valid by default and only runs computation, via a fraud proof, in the event of a challenge.
• Zero-knowledge rollups (zkRollups) — rolups that run computation off-chain and submits a validity proof to the chain.

Optimistic rollups

Optimistic rollups are named for the "optimistic" approach to executing off-chain transactions — all layer 2 transactions are valid unless challenged and proven wrong by an honest network validator.

They use a "fraud-proof" mechanism to detect invalid transactions. There is a "challenge" period during which someone can submit fraud proof to challenge a set of approved transactions.

If the proof is valid, it nullifies the faulty transaction and re-executes it to update the rollup's state. Also, malicious validators are penalized for approving wrong transactions.

However, if the rollup batch is unchallenged during the dispute period, the transaction data is successfully added to the Mainnet.

For more information, read "Optimistic rollups" (opens in a new tab).

Zero-knowledge rollups

Zero-knowledge rollups (zkRollups) are named for the Zero-knowledge Proofs mechanism. Zero-knowledge Proofs (ZKP) is a method for one party to cryptographically prove to another that they possess knowledge about a piece of information without revealing the actual underlying information. Validators on zkRollups prove a transaction’s authenticity without revealing any transaction details.

Unlike optimistic rollups, zkRollups assume all transactions are false until proven valid through ZKP. zkRollups rely on validity proofs to determine if a transaction is true or not, having the verifier ask the prover to perform a series of actions that can only be performed accurately if the prover knows the underlying information. If the prover is only guessing as to the result of these actions, then they will eventually be proven wrong by the verifier’s test with a high degree of probability. ZkRollup nodes have to provide validity proofs for all transactions to ensure that the transaction data on the main chain is valid.

For more information on how zkRollups work and ZKP types, read "Zero-knowledge rollups" (opens in a new tab) and "Zero-Knowledge Proofs" (opens in a new tab).

Which type is better?

By many, zkRollups are considered safer and faster.

The primary benefit of zero-knowledge proofs in zkRollups is the ability to leverage privacy-preserving datasets within transparent systems such as public blockchain networks.

The challenge period of optimistic rollups, that zkRollups do not have, increases the time taken for transactions to be finalized. The finality of chains with optimistic rollups is also lower than that of zkRollups. Finality is the measure of how long a user has to wait for a reasonable guarantee that the transactions will not be reversed or altered. In optimistic rollups, all transaction data must be posted on-chain to finalize transactions, while in zkRollups only validity proofs are required on-chain.

Do I need a rollup or a sidechain?

A sidechain is an independent EVM-compatible blockchain which runs in parallel to Mainnet. Sidechains are compatible with he Mainnet via two-way bridges, and run under their own chosen rules of consensus, and block parameters.

Rollups are a Layer 2 scaling solution on-top of a blockchain that increases transaction output by bundling multiple transactions into batches, which are processed off-chain.

You would need a sidechain if you need own blockchain network with custom rules and parameters. And you would need a rollup if you need hide sensitive transaction data for privacy reason and constantly process big batches of transactions.

By the way, zkRollups are considerably safer than pure off-chain scaling solutions, such as sidechains, which are responsible for their security properties.