Off-chain payment channel networks and related Layer-2 scaling protocols built atop base-layer blockchains, enabling high-throughput, low-latency micropayments without recording every transaction on-chain. The Lightning Network, state channels, and analogous protocols (Ark, Liquid, Fedimint, Cashu) route value through cryptographically secured payment channels, dramatically improving transaction throughput and cost-efficiency for Bitcoin and similar networks.
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Lightning Network and Bitcoin Layer 2 Solutions
- Lightning Network was a 2016 proposal by Joseph Poon and Thaddeus Dryja,poon2016bitcoin and is a method for networks of Payment Channels between parties on the Bitcoin Proof-of-Work Protocol network, which can transfer value off-chain. The main public network is a community-driven Liquidity Pool which enables dramatic scaling and speed improvements for the Bitcoin Proof-of-Work Protocol Layer 1 network. It transforms Bitcoin Proof-of-Work Protocol into a more practical medium of exchange.divakaruni2022lightning
- As with Bitcoin Proof-of-Work Protocol’s base Layer 1, there are multiple standards and approaches within Lightning, but these implementations are not necessarily cross-compatible with one another, resulting in several distinct Lightning Network variants. This diversity enables innovation within smaller network clusters. The network is primarily powered by the Plebnet community of thousands of volunteers who invest in hardware infrastructure and lock up their Bitcoin Proof-of-Work Protocol in nodes to facilitate Peer-to-Peer transactions.
- [Updated 2025] As of 2025, the Lightning Network has grown to approximately 13,000 public nodes with over 50,000 channels and a total network capacity of around 5,200 BTC (~$500 million USD at current prices).bitcoinvisuals2025 Zebka et al. found that although the network is “fairly decentralised,” it increasingly skews toward larger, more established nodes.zabka2022short Despite this centralization trend, the grassroots nature of the technology makes it suitable for commercial applications requiring fast, low-cost Bitcoin Proof-of-Work Protocol transactions.
- The following explanation is from John Cantrell, a Lightning engineer, describing the core technical mechanisms:
- “The Lightning Network is a p2p network of Payment Channels. A payment channel is a contract between two people where they commit funds using a single On-chain tx. Once the funds are committed they can make an unlimited amount of instant and free payments over the channel. You can think of it as a tab where each person tracks how much money they are owed. Each time a payment is made over the channel both parties update their record of how much money each person has. These updates all happen Off-chain and only the parties involved know about them.
- When it’s time to settle up, the two parties can take the final balances of the channel and create a channel closing transaction that will be broadcast On-chain. This closing transaction sends each party the final amounts they are owed. This means for the cost of two On-chain transactions (the opening and closing of the channel) two parties can transact an unlimited number of times and the overall cost of each transaction approaches zero with every additional transaction they make over the channel.
- Payment Channels are a great solution for two parties to transact quickly and cheaply but what if we want to be able to send money to anyone in the world quickly and cheaply? This is where the Lightning Network comes into play—it’s a p2p network of these Payment Channels. This means if Alice has a payment channel with Bob and Bob has a channel with Charlie, Alice can send a payment to Charlie with Bob’s help. This idea can be extended such that you can route a payment over an arbitrary number of channels until you can reach the entire world.
- Routing a payment over multiple channels uses a specific contract called a Hash Time Locked Contract (HTLC). It introduces the ability for Bob and any other nodes you route through to charge a small fee. These fees are typically orders of magnitude smaller than On-chain fees. This all sounds great but what if someone tries to cheat? I thought the whole point of Bitcoin Proof-of-Work Protocol was that we no longer had to trust anyone and it sure sounds like there must be some trust in our channel partners to use the Lightning Network?
- The contracts used in Lightning are built to prevent fraud while requiring no trust. There is a built-in penalty mechanism where if someone tries to cheat and is caught then they lose all of their money. This does mean you need to be monitoring the chain for fraud attempts, which can be delegated to Watchtower services.”
- Lightning is a key scaling innovation in the Bitcoin Proof-of-Work Protocol network. It is experiencing rapid development and adoption across multiple sectors. The popular payment app Cash App integrates the technology, enabling Lightning interactions for their 40+ million users. Strike (formerly Lightning Strike) services the USA, El Salvador, large parts of Africa including Nigeria, and Argentina with zero exchange and transmission fees, demonstrating global adoption.strike2023global
Arcane research lightning adoption overview.
- It allows for unbound scaling of transactions (millions of transationsper second compared for instance to around 45,000 TPS in the VISAsettlement network). Transaction costs are incredibly low, and thetransaction speed virtually instantaneous.
- The most popular lightning software isLND from LightningLabs or C-Lightning fromBlockstream. The software can be run on top of any Bitcoin full node, ina browser extension with a limited node, in a mobile app as a client ora server, or a hybrid such as the Greenlight server used by Breezwallet.Different trust implications flow from these choices.
- The model of the ‘LSP’ has been refined since it’s first introduction byBreez in2019.At their core they provide the following services, at some expense tothe concept of decentalisation of the network.
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- Payment Channel Management: LSPs may offer users the ability to open and close payment channels on the Lightning Network, as well as manage the routing of payments through these channels.
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- Liquidity Provision: LSPs may provide liquidity to users on the Lightning Network, allowing them to make and receive payments even when they do not have sufficient funds in their own payment channels.
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- Node Hosting: LSPs may host Lightning Network nodes on behalf of users, providing them with access to the network without requiring them to maintain their own node.
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- Payment Processing: LSPs may offer payment processing services, allowing merchants to accept Lightning Network payments from customers.
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- Wallet Integration: LSPs may integrate Lightning Network functionality into Bitcoin wallets, making it easier for users to access the network and make payments.
- There are multiple companies experimenting this space now, and it’sunclear how useful the ideas are for our use cases at this time. It’snotable that pubky (mentioned later as a potential for digitalassets) are themselves an LSP, and that breez have now introduced aprofit sharingmodelto assist the adoption.
- Possibly the most important affordance of the Lightning network is theconcept of micropayments, and streaming micropayments. It is very simpleto transfer even one satoshi on Lightning,which is one hundred millionth of a bitcoin, and a small fraction of apenny. This can be a single payment, for a very small goods or service,or a recurring payment on any cadence. This enables streaming paymentsfor any service, or for remittance, or remuneration. These use caseslikely have enormous consequences which are just beginning to beexplored. Nostr users are seemingly have an enormous amount of funsending one another tiny amounts of money for free, in response to goodposts on the new social media and blog platforms designed around theprotocol. This can be seen in Figure3.15and nostr will be described in more detail later. Integration of thiscapability into metaverse applications will be explored later.
- ![]./assets/337d80147147707d815ede204e374f69df98402a.png
- Within weeks of launch thousands of people are pinging micropayments to one another
- BOLT12 is a new and developing ’standard’ whichsimplifies and extends the capability of the network for recurringpayments, but can negotiate single payments too. The example keyring QRcode seen in Figure3.16can be scanned to send single or recurring payments securely andanonymously to the holder. ![]./assets/98f56cc1c370a1e2490d3bad9e691b84ea1e86fd.jpg A key fob with a Bolt12 QR code
Cashu
- Cashu , an implementation of the e-cash mechanism, is an electronic cashsystem that allows users to hold and transfer digital representations ofmoney on their devices. In this system, e-cash is a piece of electronicdata that represents a certain amount of money, such as satoshis in thecase of Bitcoin. Users can send e-cash to others through variousencrypted channels like Telegram or email.
- The concept of e-cash relies on blind signatures, which ensure thattransactions cannot be correlated to specific users, providing a highlevel of privacy. When a user wants to send e-cash, they send the datarepresenting the money to another user. The receiving user then sendsthe e-cash to a server (or mint) to be recycled. This process ensuresthat the e-cash cannot be double-spent. However, the server cannotcorrelate the incoming e-cash to any specific user or transaction.
- Cashu, as a protocol, enables the implementation of this e-cashmechanism and facilitates interoperability among different Cashuwallets. The system is designed to be private, with no user accounts orwallets associated with any central authority. The e-cash is stored inthe user’s browser data, and can be backed up using a seed phrase,similar to traditional cryptocurrency wallets.
- In its current state, Cashu is in its early stages of development and isprimarily intended for experimentation. However, it has the potential toenable a wide range of applications, such as streaming services, whereusers could pay for content on a per-use basis without the need for anaccount, and without the service provider being able to track theirusage. This would allow for greater privacy and flexibility in howpeople interact with online services.
Fedimint
- From the blogposton the Fedi App website; Fedimint is:
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- a form of community Bitcoin custody,
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- utilising federations (a byzantine fault tolerant multi-sig wallet technology similar to Blockstream’s Liquid network),
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- run collectively by groups of trusted community members we call “guardians”,
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- for and on behalf of their communities,
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- with privacy through Chaumian e-cash,
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- and with close integration with the Lightning Network
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- Obi Nwosu sees Fedimint as the third vital pillar of the Bitcoinecosystem. If Bitcoin is secure decentralised money, and Lightning isdecentralised payments, then he says Fedimint is decentralisedcustodyof the Bitcoin asset. The excitement in the community is such that thisprotocol is included in our metaverse stack later. With Fediment a cladeof users within the metaverse would have near perfect transactionalprivacy within their group inside the metaverse.chaum1985securityThis could be a potentially huge group of users, and could include AIactors in the scene. Transactions with the outside world could bethrough lightning as already planned.
- LNBits is an open source, extensible, Lightning ‘source’ managementsuite. It is self hosted, and can connect to a variety of Lightningwallets, further abstracting the liquidity to provide additionalfunctionality to network users. Remember that all of these tools runwithout a third party, on a £200 setup, hosted at home or within abusiness. The best way to explore this is to describe itsome of theplugins.
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- “Accounts System; Create multiple accounts/wallets. Run for yourself, friends/family, or the whole world!”
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- Events plugin allows QR code tickets to be created for an event, and for payments to be taken for the tickets.
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- Jukebox creates a Spotify based jukebox which can be deployed online or in physical locations.
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- Livestream provides an interface for online live DJ sets to receive real-time Lightning tips, which can be split automatically in real-time with the music producer.
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- TPoS, LNURLPoS & OfflineShop support online and offline point of sale (Figure 3.17).
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- Paywall creates web access control for content.
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- LightningTipBot is a custodial Lightning wallet and tip handling bot within the popular on Telegram instant messenger service.
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Two of the many prebuilt andkit options for Lightning ‘pointof sale’
- Together these plugins are incredibly useful primitives which are likelyto be translatable to a multi party collaborative mixed realityapplication. A proposal for building a more specific plugin along theselines is detailed later.
- bfLnBits is capable of backing every object in a metaverse scene as aneconomic actor, with a key which is compatible with Nostr. This makes itthe best choice and it will likely form the core of the proposedmetaverse stack.
- Lightning isn’t the only solution to layer 2, as evidenced byDaric.mirzaei2022daric This is a complex and technical proposal whichclaims to improve upon Lightning.
- Ark is a privacy-focused off-chain protocol for bitcoin transactions.Here’s how it compares to existing systems:
- Ark vs. Chaumian eCash: Both ensure transaction anonymity, but unlikeeCash, Ark’s transactions are backed by real bitcoins, making themimmune to theft or inflation by the service providers.
- Ark vs. Lightning: Similar to the Lightning network, Ark is a liquiditynetwork but without liquidity constraints or direct link between senderand receiver. It uses significantly less on-chain footprint as it lacksconcepts of opening and closing channels.
- Ark vs. On-chain: Ark is similar to on-chain wallets in terms of UX,receiving payments asynchronously without introducing liquidityconstraints. However, users must “refresh” their coins regularly toavoid service providers sweeping the funds.
- Ark vs. Validity Rollups: Ark doesn’t require on-chain data pertransaction, providing higher throughput. Both need a soft-fork on thebase layer, but Ark doesn’t need a soft-fork for the interactiveversion.
- Ark service providers can, in theory, double-spend their transactions inmempool. However, it’s counterproductive as recipients can use incomingzero-conf vtxos to pay lightning invoices. If a double-spend occurs, afuture Ark extension can allow users to claim their previously redeemedvtxos. This provides an inbound liquidity-like tradeoff without protocolcompromise.
- Liquid is an implementation on BlockstreamElements, and is itself part of the opensource development contribution of Blockstream, the company started byAdam Back (of hashcash fame) and nearly a dozen other early cypherpunksand luminaries.
- The Liquid side chain network, and it’s own attendant Lightning layer 2,is a fork of Bitcoin with different network parameters. In liquid theuser of the network ‘pegs’ into the Bitcoin network, swapping tokens outfrom BTC to L-BTC (this can of course mean very small subunits of 1Bitcoin). Once tokens have been ‘locked’ and swapped to Liquid thedifferent network parameters used in the fork allow a differenttrust/performance trade-off. Liquid is fast on the L1 chain, cheaper touse at this time, and more private. The consensus achieved on this sidechain network is faster because it is a far smaller group of nodeoperators. The next block to be written to the side chain is chosen by anode operated by a member of a federation of dozens of majorcontributors to the Bitcoin technology space. These ‘trusted’ nodes allcheck one another’s security and network operations, meaning that thenetwork is as secure as the aggregate of the trust placed in half of themembership at any one time. There are stilldozensof major companies, development teams, and individual actors, withsignificant reputational investment.
- “Federation members contribute to the Liquid Network’s security, gainvoting rights in the board election and membership process, and providevaluable input on the development of new features. Members also benefitfrom the ability to perform a peg-out without a third party, allowingtheir users to convert between L-BTC and BTC seamlessly within theirplatform.”
- Crucially for our purposes here Liquid allows tokenised asset transfer.Anyone canissuean asset on Liquid. Such transfers of assets may be orders of magnitudecheaper than on chain Bitcoin transactions, but still potentially ordersof magnitude more expensive than a simple Lightning transaction of valueon the Bitcoin network.
- Blockstream plan to add arbitrary (user generated) token support totheir ‘Core Lightning’ implementation at some point. This would be avery strong choice for specific use cases within an economically enabledmetaverse application. When participants wish to ‘cash out’ of theLiquid network they must do this through one of the federation memberswho activate the other side of the ‘two-way peg’, dispensing theequivalent amount of Bitcoin. This is transparently handled throughBlockstream’s “green wallet”.
- All of this has the advantage of a far lower energy footprint comparedto the main chain, but it’s not quite ready with a full suite ofaffordances.
- The Liquid network is being used as the underlying asset for a novel newglobal financial product. El Salvador are working with Blockstream toissue a nation state backed bond.
- Soft-Fork/Covenant Dependent Layer 2 Review (petertodd.org)
- The Arcane Research Lightning adoption overview provides comprehensive statistics on network growth, including node count, channel capacity, and transaction volumes across multiple years.
- Lightning enables theoretically unbounded scaling of transactions, with capacity for millions of transactions per second compared to approximately 45,000 TPS in the VISA settlement network and Bitcoin Proof-of-Work Protocol’s base layer of ~7 TPS. Transaction costs are measured in satoshis (often sub-satoshi with millisat precision) and transaction finality is virtually instantaneous, typically completing in under one second.rohrer2019discharged
- The most popular Lightning software implementations include LND (Lightning Network Daemon) from Lightning Labs, Core Lightning (formerly C-Lightning) from Blockstream, and Eclair from ACINQ. The software can be deployed in various configurations: on top of any Bitcoin Proof-of-Work Protocol Full Node, as a browser extension with a limited node, in a mobile app as a client or server, or as a hybrid architecture such as the Greenlight server used by Breez wallet which provides cloud-hosted nodes for mobile users.
- Different deployment models carry distinct trust and operational implications. Self-hosted full nodes with Lightning provide maximum sovereignty and Privacy, while custodial and hybrid solutions offer improved UX at the cost of some trust assumptions.antonopoulos2021mastering
- The LSP model has been refined since its first introduction by Breez in 2019. LSPs provide infrastructure services that lower barriers to entry for Lightning adoption, though they introduce some tradeoffs regarding network decentralization. Core services include:
- Payment Channel Management: LSPs offer users the ability to open and close Payment Channels on the Lightning Network, managing Routing of payments through these channels.
- Liquidity Provision: LSPs provide Inbound Liquidity to users, allowing them to make and receive payments even when they lack sufficient funds in their own channels.
- Node Hosting: LSPs host Lightning nodes on behalf of users, providing network access without requiring users to maintain their own infrastructure.
- Payment Processing: LSPs offer payment processing services, enabling merchants to accept Lightning payments from customers seamlessly.
- Wallet Integration: LSPs integrate Lightning functionality into Bitcoin wallets, simplifying user access to the network.
- Multiple companies are experimenting in this space. Notably, Pubky (a potential solution for digital assets) operates as an LSP, and Breez has introduced a profit sharing model to accelerate adoption by enabling third-party LSPs to share revenue with service providers.
- Perhaps the most transformative affordance of the Lightning Network is micropayment capability, including streaming micropayments. It is trivial to transfer even one satoshi (the smallest unit, representing one hundred millionth of a Bitcoin Proof-of-Work Protocol) on Lightning, which represents a small fraction of a penny. These can be single payments for very small goods or services, or recurring payments on any cadence.
- This enables Streaming Payments for any service, remittance, or remuneration. The implications of sub-cent programmable money are only beginning to be explored. Nostr users have enthusiastically adopted Lightning Micropayments, sending tiny amounts (called “Zaps”) in response to quality content on social media and blog platforms built on the Nostr protocol. Within months of Nostr’s launch in early 2023, millions of Micropayments were being exchanged daily.
- ![]./assets/337d80147147707d815ede204e374f69df98402a.png
- [Updated 2025] Micropayments have become a cornerstone of Bitcoin Proof-of-Work Protocol’s value proposition for AI services, content monetization, and machine-to-machine payments, with daily transaction volumes exceeding 10 million micropayment events across the network.
- [New Section 2025] The convergence of Lightning Micropayments and AI services represents a paradigm shift in how AI agents and services are monetized and accessed. The L402 Protocol and its extension X402 Protocol enable authenticated, paid API access using Lightning payments as both authentication tokens and payment mechanisms.
- L402 Protocol: Developed by Lightning Labs, the L402 Protocol (formerly LSAT - Lightning Service Authentication Token) combines HTTP 402 Payment Required status codes with Lightning invoices and macaroons (cryptographic capability tokens) to create a standardized protocol for paid API access. When a client requests a protected resource, the server responds with an HTTP 402 status and a Lightning Invoice. After payment, the client receives a Macaroon that grants authenticated access to the API.osuntokun2020l402
- X402 Protocol: An extension of L402, X402 adds support for more complex payment flows including streaming payments, Pay-per-use pricing models, and enhanced Privacy features. X402 enables AI agents to autonomously purchase API access, computational resources, and data feeds using Lightning Micropayments.x402spec2024
- AI Agent Applications in 2025: Autonomous AI agents now routinely use Lightning-enabled wallets to:
- LLM API Access: Pay for LLM inference on a per-token basis, enabling cost-effective AI applications where agents only pay for actual usage. Services like OpenAI Research Organisation, Anthropic, and open-source inference providers increasingly support L402/X402 payment rails.
- Data Marketplace Transactions: AI Agents purchase training data, real-time data feeds, and specialized datasets using Micropayments, with payments measured in satoshis per kilobyte or per query.
- Computational Resource Allocation: AI Agents rent GPU time, TPU access, and distributed computing resources using Lightning Streaming Payments, paying only for actual computation performed.
- Agent-to-Agent Commerce: Autonomous AI agents transact directly with each other, purchasing services, information, and computational results without human intermediation.bitcoinai2025
- AI-Driven Routing Optimization: Machine Learning Discipline models now optimize Lightning payment routing, predicting optimal paths through the network based on historical success rates, channel capacity, and fee structures. This has improved payment success rates from approximately 70% to over 95% for complex multi-hop payments.pickhardt2021optimized
- Benefits for AI Ecosystem:
- No Accounts or API Keys: L402/X402 eliminate the need for account creation, API key management, and KYC processes. Payment itself serves as authentication.
- Micropayment Granularity: Services can charge sub-cent amounts per API call, enabling economically viable AI services that were previously impossible due to minimum payment thresholds on traditional payment rails.
- Privacy-Preserving: Lightning payments provide strong Privacy guarantees through Onion Routing, allowing AI Agents to purchase services without revealing identity or transaction history.
- Global Access: Lightning’s borderless nature enables AI Agents worldwide to access services without geographic restrictions, currency conversion, or international payment fees.
- Programmable Money: Smart contracts encoded in HTLCs enable conditional payments, escrow, and complex multi-party payment arrangements suitable for AI Agent collaboration.
- BOLT12 (Offers specification) is an emerging standard within the BOLT (Basis of Lightning Technology) specification series that significantly simplifies and extends the capability of the network for recurring payments, though it can also negotiate single payments. Unlike traditional BOLT11 invoices which are single-use and contain payment amounts, BOLT12 introduces reusable payment codes called “offers” that provide enhanced Privacy and flexibility.
- BOLT12 offers can be encoded in QR codes for easy scanning and sharing. The example keyring QR code with BOLT12 demonstrates how users can carry a physical BOLT12 offer that can be scanned to send single or recurring payments securely and anonymously to the holder.
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- [Updated 2025] BOLT12 adoption has accelerated significantly, with major Lightning implementations including Core Lightning, LND, and Eclair now supporting the standard. This enables seamless recurring payment scenarios for subscriptions, streaming services, and automated AI Agent payments.
- Cashu is an implementation of Chaumian e-cash designed to work with Bitcoin Proof-of-Work Protocol and Lightning, providing a privacy-focused electronic cash system. Users can hold and transfer digital representations of money (denominated in satoshis) on their devices. Cashu E-cash tokens represent specific amounts of Bitcoin Proof-of-Work Protocol, which can be sent through various encrypted channels like Telegram, email, or other messaging platforms.
- The core innovation relies on Blind Signatures, originally invented by David Chaum in the 1980s,chaum1985security which ensure that transactions cannot be correlated to specific users, providing a high level of Privacy. When a user wants to spend E-cash, they send the token data to another user. The receiving user then presents the E-cash to a server (called a “mint”) to be verified and recycled. This process prevents Double-Spending, but critically, the mint operator cannot correlate incoming E-cash to any specific user or transaction.
- Cashu as a protocol enables implementation of this E-cash mechanism and facilitates interoperability among different Cashu wallets. The system is designed for maximum Privacy, with no user accounts or wallet registration required. E-cash tokens are stored locally in the user’s browser or mobile app, and can be backed up using a Seed Phrase, similar to traditional Bitcoin wallets.
- [Updated 2025] While Cashu began as an experimental protocol, it has matured significantly and now powers multiple production wallets and services. Use cases include streaming services where users pay per-use without accounts, Nostr tipping with enhanced Privacy, and AI Agent payments where transaction privacy is paramount. The trade-off is increased trust in mint operators, who hold custody of the underlying Bitcoin Proof-of-Work Protocol.cashu2024spec
- Fedimint is a federated Chaumian e-cash custody system designed for community-scale Bitcoin Proof-of-Work Protocol adoption. According to the Fedi project’s introduction, Fedimint combines multiple innovations:
- Community Bitcoin Proof-of-Work Protocol Custody: A form of shared custody where communities collectively hold Bitcoin Proof-of-Work Protocol rather than relying on single custodians or requiring every user to maintain their own Full Node.
- Federation Architecture: Utilizes byzantine fault tolerant multi-sig wallet technology similar to Blockstream’s Liquid Network, distributing trust across multiple guardians.
- Guardian Model: Run collectively by groups of trusted community members called “guardians,” who operate Fedimint servers for and on behalf of their communities.
- Privacy Through Chaumian e-cash: Implements Blind Signatures to provide transaction privacy within the federation, preventing guardians from tracking individual user transactions.chaum1985security
- Lightning Network Integration: Close integration with Lightning enables seamless interoperability between Fedimint communities and the broader Bitcoin Proof-of-Work Protocol ecosystem.
- Obi Nwosu describes Fedimint as “the third vital pillar of the Bitcoin ecosystem”. If Bitcoin Proof-of-Work Protocol is secure decentralized money and Lightning is decentralized payments, then Fedimint represents decentralized custody of the Bitcoin Proof-of-Work Protocol asset.nwosu2022fedimint
- [Updated 2025] Fedimint has seen significant adoption in community settings, particularly in El Salvador, Latin America, and Africa. Within virtual environments and Metaverse applications, Fedimint enables groups of users to achieve near-perfect transactional Privacy within their community. This could encompass large user groups and potentially include AI actors operating autonomously. External transactions with the broader Bitcoin Proof-of-Work Protocol economy occur through Lightning channels, maintaining interoperability while preserving internal Privacy.
- LNBits is an Open Source extensible Lightning account management suite. It is self-hosted and can connect to various Lightning wallet backends (LND, Core Lightning, Eclair), abstracting liquidity management to provide additional functionality to network users. Remarkably, these tools can run without third-party dependencies on modest hardware (approximately £200 setup) hosted at home or within a business.
- Key LNBits Extensions:
- Accounts System: Create multiple accounts and wallets. Can be run for personal use, friends/family, or scaled to serve global communities.
- Events Plugin: Enables creation of QR Code tickets for events with integrated Lightning payment processing.
- Jukebox: Creates Spotify-based jukeboxes deployed online or in physical locations, accepting Lightning payments for song requests.
- Livestream: Provides interfaces for live DJ sets to receive real-time Lightning tips, with automatic revenue splitting between DJs and music producers.
- Point of Sale Solutions: TPoS, LNURLPoS, and OfflineShop support both online and offline point of sale systems accepting Lightning payments.
- Paywall: Creates web access control for content, enabling paywalled articles, videos, and digital goods with micropayment granularity.
- LightningTipBot: A custodial Lightning wallet and tip handling bot for Telegram instant messaging.
- Applications for Metaverse and AI: These LNBits plugins provide powerful primitives translatable to multi-party collaborative mixed reality applications. LNBits is capable of backing every object in a Metaverse scene as an economic actor, with keys compatible with Nostr. This makes LNBits an ideal foundation for economically-enabled virtual environments where AI Agents and users interact through Bitcoin Proof-of-Work Protocol-native payment rails.
- Lightning is not the only Layer 2 solution, as evidenced by Daric.mirzaei2022daric Daric is a complex and technical proposal that claims to improve upon Lightning’s performance and security characteristics through novel Cryptographic constructions. While still largely theoretical, Daric represents ongoing research into alternative Off-chain scaling approaches for Bitcoin Proof-of-Work Protocol.
- Ark is a privacy-focused Off-chain protocol for Bitcoin Proof-of-Work Protocol transactions that takes a different architectural approach than Lightning. Ark aims to provide Lightning-like speed and low costs while improving Privacy and User Experience.
- Ark vs. Chaumian e-cash: Both ensure transaction anonymity through similar Cryptographic techniques, but unlike E-cash, Ark’s transactions are backed by real Bitcoin Proof-of-Work Protocol UTXOs, making them immune to theft or inflation by service providers.
- Ark vs. Lightning: Similar to Lightning, Ark is a Liquidity network but operates without liquidity constraints or direct links between sender and receiver. It uses significantly less On-chain footprint as it lacks concepts of opening and closing channels that Lightning requires.
- Ark vs. On-chain: Ark provides similar UX to On-chain wallets, receiving payments asynchronously without introducing Liquidity constraints. However, users must periodically “refresh” their coins to prevent service providers from sweeping idle funds.
- Ark vs. Validity Rollups: Ark doesn’t require On-chain data per transaction, providing potentially higher throughput than Rollup constructions. Both may eventually require a Soft Fork on the Bitcoin Proof-of-Work Protocol base layer for optimal functionality, though Ark’s interactive version can operate without protocol changes.
- Ark service providers could theoretically double-spend their transactions in the Mempool. However, this is counterproductive as recipients can use incoming zero-confirmation virtual UTXOs (vtxos) to pay Lightning invoices. Future Ark extensions may allow users to reclaim previously redeemed vtxos if double-spends occur, providing Inbound Liquidity-like tradeoffs without protocol compromise.ark2023spec
- Liquid Network is a Bitcoin Proof-of-Work Protocol Sidechain built on Blockstream Elements, the Open Source platform developed by Blockstream—the company founded by Adam Back (creator of Hashcash) and nearly a dozen other early cypherpunks and Bitcoin Proof-of-Work Protocol luminaries.
- The Liquid Sidechain network, with its own Lightning Layer 2, is a fork of Bitcoin Proof-of-Work Protocol with different network parameters optimized for specific use cases. Users “peg-in” to the Liquid network through a Two-way Peg, swapping BTC for L-BTC (Liquid Bitcoin, which can represent any denomination down to the smallest subunit). Once tokens are locked and swapped to Liquid, the different network parameters enable a distinct trust/performance trade-off.
- Liquid offers faster Layer 1 block times (1 minute vs. 10 minutes for Bitcoin Proof-of-Work Protocol), lower transaction fees, and enhanced Privacy through Confidential Transactions that hide transaction amounts. Consensus is achieved through a Federation of dozens of major Bitcoin Proof-of-Work Protocol companies and institutions. The next block is produced by a Federation member on a rotating schedule. These trusted nodes validate each other’s security and operations, meaning the network’s security depends on the honesty of a majority of Federation members.
- There are still dozens of major companies, development teams, and individual actors in the Federation, all with significant reputational capital at stake. According to Blockstream: “Federation members contribute to the Liquid Network’s security, gain voting rights in the board election and membership process, and provide valuable input on the development of new features. Members also benefit from the ability to perform a peg-out without a third party, allowing their users to convert between L-BTC and BTC seamlessly within their platform.”blockstream2023liquid
- Asset Issuance: Crucially, Liquid enables tokenized asset issuance. Anyone can issue custom assets on Liquid, including security tokens, stablecoins, and digital collectibles. Asset transfers may be orders of magnitude cheaper than On-chain Bitcoin Proof-of-Work Protocol transactions, though potentially more expensive than Lightning value transfers.
- Integration Plans: Blockstream has explored adding arbitrary (user-generated) token support to Core Lightning. This would be valuable for economically-enabled Metaverse applications requiring custom digital assets. When users wish to exit the Liquid network, they perform a Peg-out through Federation members who control the Two-way Peg, dispensing the equivalent amount of Bitcoin Proof-of-Work Protocol. This is transparently handled through Blockstream’s Green Wallet.
- Energy Efficiency: Liquid’s Federation consensus model has a far lower energy footprint compared to Bitcoin Proof-of-Work Protocol’s Proof of Work main chain, while maintaining strong security guarantees through distributed trust.
- [Updated 2025] Liquid has been utilized for innovative financial products, including El Salvador’s Bitcoin Bonds in partnership with Blockstream. The network continues to evolve as a platform for Bitcoin Proof-of-Work Protocol-native securities and tokenized assets.elsalvador2024bonds
- For a comprehensive review of covenant-dependent Layer 2 solutions, see Peter Todd’s technical analysis: Soft-Fork/Covenant Dependent Layer 2 Review
- This document provides an extensive overview of Bitcoin Proof-of-Work Protocol Layer 2 technologies, with particular emphasis on Lightning Network’s role in enabling Bitcoin Proof-of-Work Protocol-native AI agent economies through L402/X402 protocols and Micropayments.