With the advancement of Bitcoin adoption and the emergence of new applications, it became clear that the main network (Layer 1) has limitations, especially regarding scalability. It was in this context that Layer 2 blockchains (or secondary layers) emerged, created to improve the efficiency of the Bitcoin network without compromising its security or decentralization.

If you want to understand how these solutions work and learn about the main Layer 2 projects in the Bitcoin universe in 2025, this article is for you.

What is a Layer 2 in Bitcoin?

A Layer 2 of Bitcoin is any network or technology built on the Bitcoin blockchain with the goal of increasing its processing capacity, reducing fees, and enabling new functionalities such as smart contracts.

These solutions emerge as a response to the limitations of the main Bitcoin network, which processes an average of only 7 transactions per second and can face congestion and high fees, especially during peak times.

The central idea of Layer 2 is to take some of the 'weight' off the main network by processing transactions outside of it and then recording the results on Bitcoin to maintain the security and immutability of the data.

How do Bitcoin Layer 2s work?

There are different approaches to scaling Bitcoin through secondary layers. The main technologies used today include:

1. State Channels

They allow two parties to transact with each other off the main blockchain, opening a 'channel' where transactions occur quickly and without network fees. Only the final state of the channel is recorded on the blockchain.

2. Sidechains

These are independent blockchains that connect to Bitcoin via a two-way peg, allowing the movement of assets between networks. They have their own rules and validators but are often not considered 100% Layer 2 because they do not directly rely on the security of the main blockchain.

3. Rollups

We execute transactions off the main chain, aggregate the data, and send it to Bitcoin as a compact cryptographic proof. This technology is still under development in the Bitcoin ecosystem but promises to combine scalability with security.

Advantages of Bitcoin Layer 2s

The growth of Layer 2 solutions brings various benefits:

  • Greater scalability: more transactions per second and faster confirmations.

  • Lower fees: by processing data off the main network, transaction costs decrease.

  • Support for smart contracts: secondary layers like Stacks and RIF enable functionalities that Bitcoin does not offer natively.

  • Increased liquidity: these solutions help unlock the DeFi potential in Bitcoin, connecting it to new financial opportunities.

Main Layer 2 projects in Bitcoin for 2025

Next, we list the main projects that are leading the transformation of the Bitcoin blockchain through secondary layers.

Lightning Network

One of the most established projects, the Lightning Network allows instant payments with extremely low fees. Ideal for micropayments, it creates channels between users, in which it is possible to transact numerous times without registering each transaction on the blockchain.

With a theoretical capacity to process up to 1 million transactions per second, Lightning is essential for using Bitcoin as electronic money in everyday transactions.

Stacks (STX)

Stacks is a Layer 2 that expands what can be done with Bitcoin. It allows the creation of smart contracts, DeFi, NFTs, and decentralized applications, always anchored to the security of the Bitcoin blockchain.

Its native token, the STX, is used to operate contracts and transactions within the network. One of the highlights of the project is the launch of sBTC, an asset indexed to Bitcoin that allows decentralized exchanges between Bitcoin and other assets in the Stacks ecosystem.

Merlin Chain

Launched by Bitmap Tech, the Merlin Chain uses ZK-Rollup technology to accelerate and reduce transaction costs. With a focus on efficiency and security, it integrates decentralized oracles and on-chain anti-fraud modules.

A distinguishing feature of the Merlin Chain is its compatibility with Ethereum (ETH), which facilitates integration with dApps and expands the usability of the network. Its token, MERL, plays a governance role.

Rootstock Infrastructure Framework (RIF)

Based on the RSK blockchain, the RIF offers a suite of decentralized services — including payments, storage, and digital identity — anchored in the security of Bitcoin.

RIF is compatible with Ethereum smart contracts, making its ecosystem versatile and powerful. Its token is used to access these services, and the project has been growing with the support of IOVLabs.

CKB Public Chain (Nervos Network)

The proposal of CKB (Common Knowledge Base) is to be a Layer 2 of Bitcoin that combines the UTXO model with PoW consensus, inheriting the security of Bitcoin.

Its goal is to facilitate lighter transactions and interoperability between networks while supporting decentralized applications. The proposal is to position the token CKB as a key asset in the new generation of financial applications on the Bitcoin network.

Other relevant initiatives

Besides the projects above, it is worth highlighting the Liquid Network, aimed at large transactions with greater privacy and governance via federation, and the Statechains, which are still in development but promise privacy and scalability with new concepts of off-chain ownership transfer.

What to expect from the future of Bitcoin Layer 2s?

The trend is clear: Layer 2s are growing in importance and adoption. For the coming years, we can expect:

  • Technological advancements that make solutions more accessible;

  • Greater integration with traditional financial systems;

  • More intuitive user experiences;

  • Collaborations between projects and standardization of protocols.

By enabling new use cases such as DeFi, NFTs, dApps, and micropayments, these networks help consolidate Bitcoin as a functional ecosystem — and not just a store of value.

Layer 2s are shaping the future of Bitcoin — and you can benefit now

Layer 2 solutions are the bridge between the Bitcoin of yesterday, focused on security and decentralization, and the Bitcoin of tomorrow, faster, programmable, and efficient.

Projects like Lightning, Stacks, Merlin Chain, RIF, and CKB show that it is already possible to build a new ecosystem on the solid foundation of Bitcoin. If you follow the crypto market, it is worth keeping an eye on these initiatives and understanding how they can impact your investments — and the very future of the decentralized financial system.

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