Next, let’s invite our guest Acala co-founder & CTO Bryan chen. Bryan is not only the current Substrate core contributor, Acala & Laminar co-founder, senior Polkadot community ambassador, but also a few Substrate course instructors certified by Dr. Gavin. next, Bryan

Hello everyone, I am Chen Xiliang. I have been in contact with and participated in the ecological development of Substrate and Polkadot since 2018, and became the earliest first-round Polkadot ambassador. The first Substrate course was launched in 2019. So far, there have been many courses in Chinese and English, with hundreds of students all over the world. At the end of 19, he co-founded the Acala project, and at the same time actively participated in the construction and promotion of the Polkadot ecosystem.

Next, we officially enter the questioning session. The first question: Why did you choose Substrate to develop Karura?

Substrate is currently the most advanced blockchain development framework and the underlying framework of Kusama and Polkadot. DeFi products developed based on Substrate not only have advantages in cost and performance, but also have many natural technical features, such as supporting seamless on-chain upgrades, which can be quickly upgraded and maintained. If there is a major attack, it can also be passed Governance quickly fixes vulnerabilities.

This allows various other projects to build more different types of products based on Karura's financial protocol.

The second question concerns the relationship between Karura and Acala. Is there any technical difference between Karura and Acala? How do developers choose?

Karura is a sister network of Acala. For developers, the Substrate application chain is based on modular development, which is lighter than Ethereum Dapp. Karura also provides a series of out-of-the-box DeFi components, such as over-collateralized stable asset modules, Staking LKSM to help release liquidity, For modules such as DEX, developers can manage them not only with a clear structure, but also more convenient for later maintenance. If you want to expand, there are more references to avoid repeated development.

As far as comparison is concerned, Karura and Acala are consistent on the technical level. In addition to having a series of out-of-the-box DeFi basic product components, liquidity and existing users, it also has many innovations that cannot be realized in Ethereum at present, such as a customizable network economic system. Karura network users can use all Assets on the Karura platform are used to pay network fees; cross-chain interoperability; participation in on-chain governance without locking assets; automatic upgrades on the chain that do not require contract migration, etc.

However, all new functions will be deployed to Karura first, and will be deployed to Acala only after the operation is stable. Many innovative, but controversial or unaudited functions may also be tested on Karura, and then based on the experimental results to determine how to further improve and whether they can be deployed in Acala.

Therefore, developers who are willing to try early adopters, or hope to iterate quickly, and are not afraid of constant new changes, can give priority to Karura. Acala can be used for networks that require security first and excellent stability.

In the previous report of Electric capital, a comprehensive public statistics of the 2020 DeFi ecology was also carried out. Among all the new DeFi ecology, the number of Yearn and Acala developers increased the most, and it became one of the largest developer ecology in the Polkadot ecology.

Karura is positioned as a DeFi platform in the Kusama ecosystem. Karura provides a number of financial core protocols, including stable asset protocols, Staking liquidity release protocols, DEX, etc., laying a solid foundation for the Kusama ecosystem.

Okay, thanks to the boss for his introduction. I believe everyone can understand this logic better given the relationship between Kusama and Polkadot. I also talked about the developer ecology just now, and developers win the world. I have seen the rapid growth of Acala global developers this year. Could you please introduce several ways for developers to join Karura?

Karura has a built-in EVM contract platform, so developers can deploy to Karura through Solidity contracts. You can refer to our previous articles:Teach you how to quickly build projects on Acala

If you need to use some functions other than EVM, such as custom cross-chain interaction, you can consider implementing special additional interfaces for EVM, and then call these interfaces through contracts.

If the application is relatively low-level, such as Zhuanjie Bridge, you can consider deploying the runtime pallet directly to Karura. However, this will require an audit by the Karura Parliament and a governance vote to decide whether to access it.

We also participated in ETHDenver, the world's largest Ethereum hackathon, and set up a special bonus to help more Ethereum developers learn about the Polkadot ecology in advance. Interested developers and teams can follow us. We often set up bonuses in large-scale hackathons and give technical guidance throughout the process.

Interested developers can also watch the replay of the guide:https://www.crowdcast.io/e/acala-ethdenver-2021

I believe that more and more developers will join in enthusiastically. Next, I would like to ask, can you introduce Karura's EVM to us? Is it running successfully so far?

Yes, Karura EVM is different from other EVM platforms. In addition to the functions of EVM, it also includes additional interfaces such as oracle machine and scheduler. At the same time, in order to avoid various historical problems of Ethereum, such as the state explosion problem, 100% compatibility with Ethereum will not be achieved.

For a better user experience, users can use the polkadot.js browser plug-in, which avoids the need for users to install multiple different plug-ins.

Karura EVM can already run most of the Ethereum projects, such as Uniswap. More specifically, in terms of DeFi composability, if developers deploy smart contract DApps on Karura EVM, they can directly use native cross-chain assets, such as KSM, KAR, aUSD, renBTC, etc. Similarly, the ERC-20 deployed on the EVM can also be used for modules in the Runtime layer, such as trading in DEX, or allowing it to become one of the network's payable service fees through governance. For example, Ampleforth will deploy the AMPL contract to the Karura EVM. AMPL will be used as a native Token to pay network fees, and it can also be directly replaced in DEX.

The whole process feels seamless to developers, but in fact, this requires the native Token and Runtime modules to be added to the EVM in a pre-compiled form to make them available. A transaction initiated by a smart contract written in EVM will be compiled into a Substrate transaction and signed by Polkadot.js. The response process is completed by our SDK (bodhi.js) and converted into an Ethereum-compatible consensus.

So can you share with us the current technical contributions of the team to the Kusama ecosystem, as well as some technical innovations on Karura?

We are now developing and testing cross-chain messages with the core developers of Parity, and have recently submitted multiple codes to XCM. The open source cross-chain module we implemented is also used by several other parachain projects including Plasm to handle cross-chain.

In addition, Karura has also implemented a number of innovations, including the ability to use any currency to pay fees, free oracle machine price feeds, decentralized sovereign wealth funds and other new features, all of which are described in detail on our official account :

1、《Build an irreproducible AUM asset management barrier through a new DAO operation method》

2、《Build an irreproducible AUM asset management barrier through a new DAO operation method》

Karura is positioned as a DeFi platform in the Kusama ecosystem. Karura provides a number of financial core protocols, including stable asset protocols, Staking liquidity release protocols, DEX, etc., laying a solid foundation for the Kusama ecosystem.

Next, let’s talk about the Polkadot parachain card slot auction that has received much attention. From the Rococo test network, we can know that Acala has been connected for a while, and it is currently the most stable test parachain. So, as a Rococo in-depth test project, can you tell us about the current test progress and when do you expect Kusama to start bidding?

At present, the latest version of Rococo will support 200 validators and carry out a larger-scale stress test. If all the tests go well, then it can be preliminarily considered that the function of the parachain is stable. At the same time, Acala has also conducted cross-chain tests with other projects including Plasm, HydraDX, etc., and initially verified the realization of the cross-chain transaction function.

If everything goes well in the next test, then we may see the kusama proposal to add the system parachain statemint within 2 weeks, and then a referendum will be held. After the referendum is successful, when the waiting period is over, we can see kusama The first parallel chain of . Then there will be a few weeks of testing on kusama, and if everything goes well, the referendum proposal to start the parachain can be carried out.

In fact, there are many newcomers here, who may not understand this logic so well. Can Bryan tell you more about the mechanism of the slot auction?

good

Parachain auctions take one slot at a time, which can be divided into up to 4 periods. Each time period on Polkadot is half a year, so a maximum of 2 years can be filmed at a time. The length of each period of kusama has not yet been determined. The initial estimate is 3 months, so the longest auction cycle is 1 year.

Then the duration of each auction is undecided, we estimate it is about 2 weeks. One slot is auctioned at a time, and the auction of the second slot will start immediately after one auction, and so on. The auction will not stop until the number of parachains shows that there is a situation that affects the stability of the network. At the same time, the code will be optimized and iterated, and once the stability is restored, slots will continue to be auctioned.

Polkadot and Kusama use candle auctions, which are divided into two periods. In the first period, you can bid arbitrarily, and the highest price will take effect at the end. In the second period, you can also bid at any time, but after the second period is over, it will be randomly selected. A block after the first period is used as the end time. Whoever has the highest bid in this block wins. So here I suggest that you directly contribute all the amount you want to contribute at the end of the first cycle, instead of bidding at the end of the second cycle, especially at the end of the cycle, because there is a high probability that the bid will be judged invalid.

The last thing I want to ask is, whether it is Acala or Karura, they all want to become the DeFi center of Polkadot and Kusama. In the future, there will definitely be smart contracts based on Acala or Karura. As a project party, what will happen at different stages? What kind of technical support?

First of all, we will have technical support, and will help you provide all-round support from multiple directions such as architecture design, product design, and code implementation. Then you can also apply for treasury fund sponsorship. As long as the parliament approves, you can get the support of ACA/KAR. For details, you can refer to Polkadot or kusama treasury. In addition, our dSWF can also be used to invest in excellent ecological projects, providing funds to support the purchase of partial ownership of ecological projects. Of course, this also needs to be governed and decided by ACA/KAR token holders.

If the final project is very successful, you can also consider becoming a parachain yourself. As an early parachain project, we naturally have the richest experience and can provide more help. After becoming a parachain from the Acala platform, it can continue to interact with Acala users and other protocols through the cross-chain protocol, and also has the benefits of its own chain.

An inappropriate example is that Compound has changed from an Ethereum contract project to its own independent Compound Gateway.