1. Why do we need a second layer?
Bitcoin has achieved what no digital asset has in terms of security and decentralization, yet it still processes about 7 transactions per second, with a block every ten minutes and fees that can exceed tens of dollars during peak times. These limitations make it unsuitable for fast payments or complex applications. Second layers (L2) were born to separate the core security of the first layer (L1) from the speed and flexibility required for widespread daily use, without compromising the Bitcoin protocol itself.
2. How do second layer solutions work?
The core idea is simple: transactions are executed off-chain and then a summarized version is sent to L1 for final settlement. This is akin to adding 'side lanes' to a busy highway; this way, we achieve thousands of transactions per second with fees of a fraction of a cent, while security ultimately relies on Bitcoin.
3. Jack Dorsey: 'Use it or die'
The co-founder of Twitter and CEO of Block believes that Bitcoin will not remain established as a global asset unless it becomes an instant payment method. His company has already started testing Lightning payments at the Bitcoin 2025 conference, aiming to make it available to four million Square users in 2026. At the same time, Dorsey confirmed that focusing solely on Lightning is a mistake; multiple second layers should be tested to ensure the system's flexibility.
Real Adoption Guide: In April 2025, Coinbase announced that 15% of its Bitcoin transaction volume goes through Lightning, proving the demand for near-instant payments.
4. The five pivotal projects in 2025
Lightning Network
Technology: Bi-directional payment channels, final settlement on L1 upon opening or closing.
Advantages: Settlements in under seconds, fees less than $0.01, better privacy
Its status today: Thousands of nodes and a capacity exceeding 6,000 BTC, with increasing adoption from global exchanges and merchants.
Technology: Proof of Transfer (PoX) — uses Bitcoin as a consensus layer and establishes its smart contracts on its chains
Applications: DeFi, NFT, and building dApps in Clarity language.
Market: Market capitalization of approximately $1.1 billion on June 12, 2025
Rootstock Infrastructure Framework ($RIF )
Technology: Sidechain compatible with EVM, secured through merging with Bitcoin mining. Recently, the chain has been protected by about 81% of Bitcoin's mining power.
What distinguishes it: Two-way bridge and a mature DeFi environment.
Technology: ZK-Rollup aggregation with on-chain fraud proofs.
Achievement: Upon launch in 2024, it gathered $3.5 billion TVL within 30 days, making it the fastest-growing L2 in the Bitcoin environment.
Goal: Transfer original Bitcoin assets and gaming applications to a low-cost transaction environment.
Nervos Network ($CKB )
Technology: A multi-layer 'cell' architecture that allows the operation of integrated secondary chains with the UTXO model.
Market: A capitalization of approximately $189 million in June 2025
Added Value: A flexible base layer that supports interoperability and scalability across sidechains.
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