How to build a dApp on Polkadot?

They represent passive stakeholders and are elected to perform two important governance roles: to propose referenda and to veto malicious or dangerous referenda.They ensure security for the relay chain by participating in consensus with other validators, validating proofs from collators, and staking DOTs.With so many blockchain protocols being developed, it is imperative we understand their purpose, their USP, and the problems they solve.

One of the biggest limitations that blockchains suffer from is a lack of interoperability. This points to blockchains’ inability to communicate with one another because of their siloed structure.

Let us consider a simple example to understand the problem of interoperability: if you are into gaming, you would know that it is not possible to play an Xbox game on PlayStation and vice versa. For a game to be interoperable across Xbox and PlayStation, it must be developed in two separate iterations for the two consoles.

Similarly, numerous challenges arise when implementing a solution built on one blockchain platform onto another platform. The blockchain community recognizes this lack of interconnectedness and communication among blockchains as a major structural flaw limiting the technology’s widespread adoption. This problem has, in fact, created several barriers in realizing a truly decentralized ecosystem encompassing multiple blockchains.

Polkadot, sometimes also referred to as the blockchain superhighway, solves this problem by delivering superior blockchain interoperability, bridging the gaps in the vast blockchain network.

Polkadot is like an all-in-one gaming console that can read both PlayStation and Xbox games. Clearly, gamers would prefer to use this console over others because it would allow them to play games of their choice without worrying about their device’s compatibility.

Therefore, we can think of Polkadot as an all-in-one blockchain that supports all types of decentralized solutions and protocols by facilitating interoperability and interconnectedness among them. With fewer cross-chain limitations, Polkadot stands to resolve the problem of interoperability in the blockchain ecosystem. And no, it does not just address the interoperability problem; it also resolves issues linked to scalability and security. Let us dive a little deeper and understand the working of the Polkadot network and the benefits of developing on this platform, and let us learn how to build a dApp on Polkadot.

• What is Polkadot?
• Polkadot’s architecture
• Cross-blockchain compatibility: Why is interoperability critical in the world of blockchains?
• Why build on Polkadot?
• How to build a dApp on Polkadot?

What is Polkadot?

Polkadot is a next-gen blockchain protocol that can bring an entire network of purpose-built blockchains together, enabling them to operate seamlessly even on a large scale. Because Polkadot facilitates data exchange among different blockchains, it unlocks possibilities for a wide variety of real-world use cases.

Although blockchains have already demonstrated their potential in several fields such as web decentralization, finance, governance, identity management, and asset tracking, design limitations in almost all previous and most existing systems could hinder their widespread adoption. Polkadot’s design provides solid advantages over many existing and legacy networks, including cross-chain composability, transparent governance, upgradeability and scalability, and heterogeneous sharding.

Polkadot’s architecture

Polkadot combines numerous heterogeneous blockchain shards or parachains into a unified network. These chains are secured by and attached to the Polkadot relay chain. They can also communicate with external networks with the help of bridges. Here are the most important components of the Polkadot network based on the roles they play.

Components that perform parachain consensus roles:

• Relay Chain: The relay chain is at the heart of Polkadot’s architecture and is responsible for the network’s consensus and cross-chain interoperability and security.
• Parachains: These are sovereign blockchains that can optimize their functionality for different specific use cases. For continued connectivity with the relay chain, parachains can lease a slot or pay as they go. Parachains have their own tokens.
• Bridges: These special blockchain components facilitate connectivity between Polkadot shards and external networks such as Bitcoin and Ethereum.
• Nominators: They keep the relay chain secure by choosing trustworthy validators and staking DOTs.
• Validators: They ensure security for the relay chain by participating in consensus with other validators, validating proofs from collators and also staking DOTs.
• Collators: They produce proofs for validators and are responsible for the maintenance of shards by obtaining shard transactions from users
• Fishermen: They are primarily involved in the oversight and monitoring of the network and bring any bad behavior to validators’ notice. Any parachain full node or collator can shoulder the role of a fisherman.

Components that perform Polkadot Governance roles:

• Council Members: They represent passive stakeholders and are elected for performing two important governance roles. First, to propose referenda. Secondly, to veto malicious or dangerous referenda.
• Technical Committee: It comprises technical teams responsible for building Polkadot. The committee can join the council members in proposing emergency referenda.

If you want an in-depth analysis of blockchain’s architecture with a detailed infographic, go through this insight.

Cross-blockchain compatibility: Why is interoperability critical in the world of blockchains?

Blockchain’s success and widespread adoption depend on how well different blockchain networks interact and integrate. Interoperability among blockchain networks refers to their ability to communicate with one another for information sharing to be seamless. Technically, interoperability makes it possible to see, access, and share information across different blockchain networks.

The fulfilment of the vision of interoperable blockchains, therefore, rests on a number of abilities and functionalities, including facilitating switching of one underlying platform for another, conducting transactions with other chains, integrating with existing systems, and managing transactions among deployments on the same chain.

It is easy to infer why interoperability is not just desirable but critical for blockchains, especially when collaboration and interaction are such important determinants of growth for enterprises.

Interoperability is the only way to realize the promise of scalability of enterprise-grade blockchains. True interoperability will facilitate execution of smart contracts, development of partnerships, smooth information sharing, sharing of solutions, and a more user-friendly experience.

Interoperability in the blockchain ecosystem also helps eliminate intermediaries and third parties often associated with centralized systems.

Why build on Polkadot?

Heterogeneous Sharding

All blockchains make different trade-offs to support specific features and use cases. As chain specialization increases, so will the need for connection or communication among them. Polkadot, a sharded blockchain, connects multiple chains in one network. This allows the chains to process transactions simultaneously and exchange data with each other with security guarantees.

Polkadot’s heterogeneous sharding model allows each chain to be optimized for specific uses rather than having the chain conform to a one-size-fits-all model. With more chains and specializations, Polkadot provides the premise for endless innovations.

Scalability

One blockchain will not be enough to support a bustling future full of dApps. Because of their limited throughput and lack of runtime specialization, early blockchains were unable to scale in many real-world applications.

Polkadot allows multiple transactions to be processed simultaneously by bringing multiple specialized chains into one sharded system. This eliminates bottlenecks in transactions that are processed one by one on many older networks.

Polkadot’s future plans include a nested relay chain feature, which will allow for greater scaling. This feature will increase the number and types of shards that can be added to the network.

Upgradability

We are used to having our browsers, apps, and games updated frequently. Developers find and fix bugs before they cause serious problems. New features are also added when better solutions become available. Blockchains, like all software, need to be updated to remain relevant. However, it is much more difficult to update a blockchain than an application, game, or browser.

To upgrade a traditional blockchain, the network needs to undergo forking, which takes several months of work. Additionally, if there is a contentious hard fork, the entire community could fall apart. Polkadot makes the process easier by allowing blockchains to upgrade without having to fork the chain.

Polkadot can allow for such forkless upgrades because of its transparent, on-chain governance system. Polkadot’s governance system allows projects to be agile and adaptable to the changing pace of technology. This feature significantly lowers the risks associated with contentious hard forks, which can be a significant barrier to the entry of interested organizations.

Transparent governance

Blockchains were not subject to formal governance in their early days. Therefore, individual stakeholders could not propose or veto changes to protocols. However, Polkadot is a different story altogether. Any person who has DOTs, Polkadot’s native currency, is a part of the network’s governance system.

All DOT holders can vote on existing proposals and propose fresh amendments to the protocol. They can also help elect members of the council that act as passive stakeholders in Polkadot’s governance system.

Cross-chain composability

Polkadot encourages collaboration by design. Blockchains in their early days were closed off to other networks. As the number of blockchains for specific uses cases increases, so does the need for interoperability and communication across chains.

Polkadot’s cross-chain compatibility and message distribution allow shards to communicate, exchange value, and share their functionalities. This opens the door for a new wave of innovation. Polkadot’s ability to connect blockchains means that shards of Polkadot can interact with DeFi protocols and crypto assets on other networks, such as Ethereum.

How to build a dApp on Polkadot?

Substrate offers all the vital components needed for seamless dApp development on Polkadot. It helps you focus on building specific customizations and features as per your project’s needs.
It is easy to set up a blockchain application using a working, out-of-the-box, Substrate-based node template.

Prerequisites for building a dApp on Polkadot

To build a dApp using Substrate, here’s what you’ll need:

• Rust, installed locally on your computer and configured to create a development environment.
• Basic knowledge of software programming and the use of terminal.

Step 1: Set up a blockchain application with Substrate

There are preformatted templates on Substrate that you can use to set up a development environment. These templates help add more customizations and features when developing using Substrate.

git clone https://github.com/substrate-developer-hub/substrate-node-template

Run these commands to integrate Nightly build with Rust:

rustup update nightly
rustup target add wasm32-unknown-unknown --toolchain nightly

Now, change directory into the ./substrate-node-template folder. Then check out to the latest version inside the repository:

cd substrate-node-template
git checkout latest

The repository stores Rust files which you can modify as per the customizations or features that you need in your project.

Apply the under-mentioned commands to compile and run the node template within your project.

$ cargo build --release
2021-12-16 00:36:30 Running in --dev mode, RPC CORS has been disabled.    
2021-12-16 00:36:30 Substrate Node    
...
2021-12-16 00:36:33  Highest known block at #0    
2021-12-16 00:36:33  Prometheus exporter started at 127.0.0.1:9615    
2021-12-16 00:36:33 Listening for new connections on 127.0.0.1:9944.    
2021-12-16 00:36:36  Starting consensus session on top of parent 0x4bbcc70ccccc322d314a5df12a814c28d40e6879b7b930df5ac5a50fe4be4c30    
2021-12-16 00:36:36  Prepared block for proposing at 1 (1 ms) [hash: 0x18f1c7bf91a1544c9a0e35ac08c8f036b4cb2f8d8297233fffadb94022b982a7; parent_hash: 0x4bbc…4c30; extrinsics (1): [0x6458…325e]]    
2021-12-16 00:36:36  Pre-sealed block for proposal at 1. Hash now 0xf10d170d82617ff5df6752dc911d3483badf34b005c8c48a46aeb6b708c915b
2, previously 
0x18f1c7bf91a1544c9a0e35ac08c8f036b4cb2f8d8297233fffadb94022b982a7.    
2021-12-16 00:36:36  Imported #1 (0xf10d…15b2)    
2021-12-16 00:36:38  Idle (0 peers), best: #1 (0xf10d…15b2), finalized #0 (0x4bbc…4c30),  0  0    
...  
2021-12-16 00:36:42  Pre-sealed block for proposal at 2. Hash now 0x409138fda4f59dc093dce60fefbaca31c354ce18cef1bbea6f69a5009af6e0f4, previously 0x484e81ea10a15f04a640a595cb51d41eecc05919b4a16839852ba4d8a69440e1.
...

In the terminal output you see above, your app produces new blocks and attains consensus for the state they define.

In the next step, you set up a frontend application to enable interaction with your dApp currently running on the terminal. Run the following commands by opening a new terminal session:

git clone https://github.com/substrate-developer-hub/substrate-front-end-template

Now, you need to change directory into the freshly created folder, substrate-front-end-template, and then install the required dependencies for the user interface:

yarn install

Once you have successfully installed the required dependencies, start it with the yarn start command. When done, you have successfully accomplished Polkadot dApp development.

Step 2: Test and deploy your Polkadot dApp

To test your application, you can use Rococo, a popular Polkadot parachain testnet, which uses the proof-of-authority consensus mechanism. You can also use the Westend testnet. However, Rococo would be more convenient to use. Once tested, your dApp is ready to be deployed.

Conclusion

While there are diverse, impressive capabilities within individual blockchain ecosystems like Ethereum, nothing will make sense in the long run without the ability of such networks to interact meaningfully with one another. Cross-chain compatibility, also referred to as interoperability, is, therefore, critical in blockchain’s mass adoption as a disruptive, pan-industry technology. With its multichain architecture, Polkadot answers every question linked to interoperability and scalability. The network’s community is working heads-down to help blockchain technology reach a true enterprise-level maturity, so we can have a wider variety of power-packed, blockchain-enabled products and services in the future.

If you’re searching for an experienced blockchain development company to build a dApp or integrate your existing app with the Polkadot platform, we are the right development partner for you. Our blockchain experts will help you convert your dream project into reality.