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What are Sidechains? – A Detailed Guide

What are Sidechains? – A Detailed Guide

Sidechains are independent chains that work adjacent to a parent blockchain, also called a mainnet. Learn more about what are sidechains in...

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Blockchain technology has revolutionized the way we handle transactions and manage data securely. However, as blockchain networks continue to grow in popularity, certain limitations have emerged, particularly regarding blockchain scalability, flexibility, and interoperability. Sidechains have emerged as a promising solution to address these challenges, offering a way to expand the capabilities of blockchain networks while maintaining their security and trustworthiness.

This article will answer questions like what is sidechain and how to use sidechain?, along with exploring their components, benefits, and limitations.

What is a Sidechain? 

Before we dive into the intricacies of sidechains, let’s start with a simple definition. A sidechain is an auxiliary blockchain that runs parallel to the main blockchain, connected to it through a two-way peg mechanism. It operates independently yet retains a strong link to the main chain, enabling assets to be securely transferred between the two. 

In other words, a sidechain is like a sibling blockchain that can handle specific functions or applications while benefiting from the main blockchain’s security and trust.

How to Use a Sidechain / How do Sidechains Work? 

Now that we understand what a sidechain is, let’s explore how it works in practice. Sidechains are designed to address the issues of scalability, speed, and functionality that can sometimes hinder traditional blockchain networks. By offloading certain tasks or transactions to a separate chain, sidechains help alleviate the burden on the main blockchain, allowing for faster processing times and increased capacity. 

When users want to move assets or data from the main blockchain to a sidechain, they lock the assets on the main chain and create a corresponding representation on the sidechain. This process is known as “pegging,” ensuring that the assets are effectively locked on the main chain while being available for use on the sidechain. 

Similarly, when a user wants to move assets back to the main chain, they destroy the sidechain representation and unlock the assets on the main chain. This two-way peg mechanism ensures the assets are securely and seamlessly transferred between the two chains.

Components of Sidechains 

To better understand sidechains, we must familiarize ourselves with the key components that make them function. Two components primarily play a vital role in sidechain operations: the main chain and the sidechain. 

  • The main chain, as the name suggests, is the primary blockchain network that acts as the anchor for the sidechain. It provides the necessary security and consensus mechanism, ensuring the integrity and immutability of the entire system. Examples of popular main chains include Bitcoin and Ethereum
  • On the other hand, the sidechain is the auxiliary blockchain that runs parallel to the main chain. It has its own set of rules and parameters, allowing it to handle specific functions or applications more efficiently. The sidechain operates using a separate consensus mechanism, which may differ from the main chain’s. This flexibility allows sidechains to be customized to cater to specific requirements, such as faster transaction times or privacy features.

How is Two-Way Peg Used in Sidechains? 

The two-way peg mechanism is a crucial element of sidechains, enabling the seamless transfer of assets between the main chain and the sidechain. It ensures that the assets remain secure and intact throughout the process. 

Users who want to move assets from the main chain to the sidechain initiate a peg-in transaction. This transaction involves locking the assets on the main chain and creating a corresponding representation on the sidechain. The peg-in transaction is verified and validated by the main chain’s consensus mechanism, ensuring the process’s integrity. 

Conversely, when users want to move assets from the sidechain back to the main chain, they initiate a peg-out transaction. This transaction involves destroying the sidechain representation and unlocking the assets on the main chain. Again, the peg-out transaction is validated by the sidechain’s consensus mechanism, guaranteeing the assets’ security. 

The two-way peg mechanism serves as the bridge that connects the main chain and the sidechain, allowing for the seamless transfer of assets while maintaining the overall security and trust of the system.

What is the Use of Smart Contracts in Sidechains? 

Smart contracts, the self-executing contracts with their terms written directly into lines of code, play a crucial role in sidechains. Smart contracts enable the automation and enforcement of agreements, allowing for the execution of predefined conditions without the need for intermediaries. 

In the context of sidechains, smart contracts enhance the functionality and flexibility of these auxiliary blockchains. They enable the creation and enforcement of specific rules and conditions within the sidechain, facilitating the execution of complex transactions and applications. Smart side-chain contracts can be tailored to suit various use cases, such as decentralized finance (DeFi), supply chain management, and decentralized applications (dapps)

Integrating smart contracts in sidechains empowers developers and users to build and utilize decentralized applications more efficiently and easily. It opens up a world of possibilities where different sidechains can cater to specific applications or industries while still being interoperable with the broader blockchain ecosystem.

Benefits of Sidechains 

Now that we know ‘what is sidechain?’ and ‘how to use sidechain?’, let’s delve into the benefits of this innovative approach to scalability in blockchain:


One of the key advantages of sidechains is their ability to address scalability issues in blockchain networks. The main chain is relieved of congestion by allowing specific use cases or applications to be offloaded onto sidechains, resulting in faster transaction processing and increased throughput.


Sidechains offer a sandbox environment for developers to experiment with new features and upgrades without risking the stability and privacy of the main chain. This flexibility allows for continuous innovation and rapid iterations, driving the evolution of blockchain technology.


Sidechains provide a means to diversify the capabilities and functionalities of blockchain networks. Each sidechain can be tailored to serve a specific purpose, such as privacy, decentralized finance (DeFi), or gaming, catering to the diverse needs of users and expanding the blockchain ecosystem.

Limitations of Sidechains  

While offering certain advantages, sidechains also have limitations that need to be considered. These limitations include security concerns, reduced decentralization, interoperability challenges, sidechain congestion, high operational costs, and the potential for fragmentation.

1. Security 

One limitation of sidechains is the issue of security. Sidechains rely on a two-way peg mechanism to transfer assets between the main and side chains. This mechanism introduces a potential point of failure, as any vulnerability in the peg could compromise assets or the entire sidechain.

2. Less Decentralization 

Another limitation is the reduced level of decentralization in sidechains. Since sidechains are connected to the main blockchain, they often rely on a smaller set of validators for consensus mechanisms. This concentration of power can be seen as a trade-off for scalability in blockchain and other benefits provided by sidechains.

3. Interoperability Challenges 

Interoperability is a challenge when it comes to sidechains. Each sidechain operates independently and may have its own set of rules and protocols. This can hinder the seamless transfer of assets and data between different sidechains or between a sidechain and the main blockchain. Standardization and compatibility across various sidechains remain an ongoing concern.

4. Sidechain Congestion 

Sidechains can also suffer from congestion issues. If a popular sidechain experiences a sudden surge in activity, it may struggle to handle the increased transaction volume, leading to delays and higher fees. The scalability of sidechains is essential to ensure efficient processing of transactions and avoid congestion.

5. High Operational Cost 

Operating a sidechain can be expensive. It requires infrastructure, maintenance, and ongoing development efforts. Moreover, sidechains may necessitate additional security measures and auditing processes, increasing the overall operational cost. These costs can hinder smaller projects or organizations looking to leverage sidechains.

6. Fragmentation

The proliferation of multiple sidechains can result in fragmentation within the blockchain ecosystem. With numerous sidechains catering to specific use cases, there is a risk of segregating the blockchain community. Fragmentation can limit interoperability and collaboration, potentially hindering the growth and adoption of sidechain technology.

Examples of Sidechain Blockchains 

Examples of Sidechain Blockchains 
Source – Pinterest

Despite their limitations, several sidechain blockchain implementations have gained prominence in the crypto space.

The Liquid Network 

The Liquid Network is a sidechain developed by Blockstream. It aims to enhance Bitcoin’s functionality by enabling faster transactions and confidential asset issuance. The Liquid Network provides a secure and confidential platform for exchanges, traders, and other participants in the crypto industry.


RootStock (RSK) is a sidechain platform that brings smart contract functionality to the Bitcoin network. It enables developers to build dapps using Solidity, the same programming language used in Ethereum. RSK aims to leverage Bitcoin’s security while offering the benefits of smart contracts and higher scalability.


Polygon (previously known as Matic Network) is a layer 2 scaling solution that includes a sidechain framework. It addresses Ethereum’s scalability issues by allowing developers to build and connect their sidechains to the Ethereum network. Polygon offers faster and cheaper transactions while maintaining compatibility with Ethereum’s smart contracts.


Sidechains present a promising approach to address scalability and functionality limitations in blockchain networks. Their benefits are plenty, primary of them being the fact that they bring increased scalability in blockchains!

We do hope this post has answered your questions of ‘what is sidechain?’, ‘how to use sidechain?’, and ‘what are the benefits of sidechain?’ satisfactorily!

Frequently Asked Questions (FAQs)

1. What are Sidechains in Blockchain? 

Sidechains in blockchain are separate blockchain networks that are connected to the main blockchain. They allow for the transfer of assets and data between the main chain and the sidechain, providing additional functionality and scalability while leveraging the security of the main blockchain.

2. Are Sidechains Layer 2? 

Sidechains can be considered a form of Layer 2 solution. Layer 2 refers to a secondary blockchain or protocol that operates on top of the main blockchain to address scalability and performance issues. Sidechains are often used as a Layer 2 solution to offload transactions and computations from the main blockchain.

3. What is the Difference Between Sidechain and Off-chain? 

A sidechain is a separate blockchain that acts as a node to the main blockchain, allowing for the transfer of assets and data between the two. In contrast, off-chain refers to transactions or computations outside the main blockchain altogether. 

Off-chain solutions can include state channels or payment channels where transactions are settled later on the main chain. Sidechains are a more integrated approach that maintains a connection to the main blockchain.

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