Dymension's RollApps: Scaling Solutions with Enhanced Security and Sustainability

There’s a new kid on the block — RollApps. RollApps are Dymension’s solution to scaling. They are application-specific blockchains minus the consensus overhead, leaving just a highly scalable execution environment. RollApps use a common shared security framework, the Dymension Hub. The IBC-enabled hub allows for a connection to all other IBC-enabled chains, as well as communication between deployed Dymension RollApps, creating greater network effects as more applications are deployed.
RollApps are autonomous, think Texas, not USA. Texas is free to focus on attracting quality companies to head over and build (Howdy Elon!), all while not having to directly deal with the security overhead of uncle sam’s army.
Back to crypto, what do we mean by autonomous? Each Dymension RollApp maintains its own token as the network fee. So no more paying Ethereum when you are using Curve (think more use-cases and value accrual to Curve token holders). Users pay fees to the RollApp rather than Dymension, boosting app sustainability. At this stage some may wonder what role does Dymension play in all of this? RollApp security and agreed upon state of the application is maintained by the Dymension settlement layer which requires RollApp sequencers (the operators of the application) to stake DYM tokens to participate as part of the ecosystem.
As the name implies RollApps are app-specific rollups which come with their own set of advantages compared to blockchains — namely orders of magnitude of higher throughput and much lower latency (If you’re not too familiar with what are roll ups take a look at our previous article). In short, they execute transactions off-chain and post data and state updates on-chain. With the data posted, anyone can submit a fraud proof and earn slashing rewards in case of a fraudulent state update.
RollApps operate under fraud proof design allowing for greater scale and relying on just one honest participant for a well functioning system. One honest participant means that only one actor needs to prove that a malicious action was committed by the RollApp sequencer and if so the sequencer gets slashed. In technical jargon this is known as 1 of N trust assumptions¹. You can compare this to the usual N/2 of N consensus assumptions that PoW blockchains operate under.
https://vitalik.ca/general/2020/08/20/trust.html
To give a bit more context on where RollApps come from, we need to look at the Cosmos ecosystem. Cosmos is a decentralized network of independent, parallel blockchains (App-Chains) powered by Tendermint. One of the main factors that makes Cosmos’ tech extremely robust is the segregation of application logic and the consensus and networking. Although the Cosmos app-chain design is considered monolithic, it showcases the advantages of a modular architecture. This approach is amplified with RollApps, as the system is completely modular.

App-Chain Diagram

In many ways RollApps are very similar to App-chains. They too are a set of interconnected independent chains that compose a wider network. Similarly to App-chains, RollApps are also application-specific, and they too have their own token which can be used to pay for network fees. There will even be an SDK for rollups, the RollApp Development Kit (termed RDK). But, as much as they are alike, there are still a few major differences which constitutes the reason for their creation. Namely, allowing for higher throughput, lower latency and substantially easier bootstrapping than any monolithic blockchain.
So, a disaggregated execution layer from the settlement layer? Astute readers might think of Polkadot, but unlike Polkadot’s para-chains, deploying a RollApp is permission-less, does not require participating in an expensive auction and slots are virtually limitless. Similar to Cosmos, Dymension believes deployment should be made as easy as possible to encourage a thriving ecosystem. Dymension aims to enable developers to deploy RollApps as easy as deploying an AWS instance.
By design, Dymension’s settlement hub is a lean machine. In-line with the modular blockchain framework, data is passed down to a disaggregated Data Availability Layer² and a merklized state root is passed to Dymension’s settlement layer. Dymension’s validators are responsible for maintaining the current state and handling any fraud disputes or malicious RollApp sequencers. For example, if a RollApp is censoring its users, the user can force a RollApp to accept a transaction by interacting directly with the Dymension Hub.
In conclusion, RollApps architectural advantages mostly resemble the familiar app-chains, yet RollApps also possess impactful improvements for the future of decentralized applications. Dymension’s team is looking forward to the next steps in this exciting building process as we edge closer and closer to the release of the litepaper and a following testnet. Dymension welcomes new enthusiastic community members as a new optimal design space for developers is in the workings.
Back in April, the Dymension core team introduced a soft roadmap portraying an overview of how we see the protocol development moving forward. Today we re-visit it so we could provide the community with an updated version of the path forward.
The recent release of the litepaper provided an overview of the high level design and novel technology being built by the Dymension core team. Core concepts like RollApps, RollApp Virtual Machine and the embedded AMM were presented to the public.
As with any impactful and complex mission, we iterate over the planning process and breakdown the Dymension roadmap into concrete milestones which will lead us towards achieving the ambitious goals that we set out to accomplish.

Milestone #1 Local Dymension ⌘

The release of Dymension’s GitHub, documentation portal and tutorials will enable you to:

1. Run a full node of Dymension’s settlement hub locally and prepare for testnet.
2. Build a RollApp — Build a checkers-game RollApp which settles on your local Dymension hub node.
3. Build a WASM RollApp — Develop and deploy CosmWasm smart contracts on top of your WASM RollApp.
4. Build an EVM RollApp — Develop and deploy Solidity smart contracts on top of your EVM RollApp and unlock compatibility with the entire Ethereum eco-system. (The next documentation release will include a tutorial for building an EVM RollApp)

In the previously published roadmap we expected to deploy a vanilla SDK chain and a flagship rollup on testnet. After much thought, we decided to focus on shipping capabilities which promote a truly useful testnet, ergo we will roll-out the testnet with two RollApps💈!

Milestone #2 Testnet Launch w/ EVM and WASM RollApps 💈

A non-incentivized public testnet with two RollApps, one for the folks who love developing in Rust on CosmWasm and the other for those who love coding in Solidity with the EVM. Both RollApps will operate under a single sequencer configuration run by the Dymension team.

Milestone #3 Incentivized Testnet

Battle testing the system and preparing Dymension for the genesis event.
At this point we expect that some or most of the following core features to be operational, with the timelines varying between testnet to post mainnet.

1. Inter-RollApp Communication (IRC) allowing users to move from one RollApp to another via the Hub.
2. IBC connection with the Dymension settlement Hub enabling users to go from RollApp to any IBC-enabled chain and back!
3. Embedded AMM integrated into the settlement hub for concentrated and easy liquidity access for RollApps.

Milestone #4 Mainnet ⌘

Needless to say that the Genesis event is a monumental milestone which will unveil a lot of exciting aspects about DYM the asset, token distribution, the Dymension foundation and other juicy details which will be shared and discussed with our community members.
From a technical perspective, mainnet will continually grow into the Dymension Vision which includes the following goals:

• The challenging implementation of a functioning fraud proof system that will allow RollApps to properly progress towards their permission-less expansion.
• Decentralizing RollApps by introducing multi-sequencer capabilities. Accomplishing the above will reduce trust assumptions and unleash extensive value accrual for the DYM asset.
• At this point we estimate Dymension will ascend and begin to scratch it’s potential as it becomes a truly decentralized internet of RollApps.

The Dymension core team is working around the clock to get the protocol off the ground. While we are taking the conservative approach of not specifying specific dates, we are very optimistic (by design 😉) regarding the timelines, so tune in and buckle up.