Ark is a layer-two protocol for making off-chain Bitcoin transactions. Initially published on the bitcoin-dev mailing list as TBDXXX by Burak, is has since been named Ark and the protocol design has advanced significantly.
The Ark protocol is a payments system where people can make Bitcoin transactions at very low cost and without requiring any setup. The Ark model very closely resembles the UTXO model, which is a key differentiator with Lightning.
Ark is a scaling solution for Bitcoin that involves moving transactions off-chain. Ark executes transactions outside of the Bitcoin main chain but posts transaction data back on-chain in a compressed format. Ark servers bundle multiple off-chain transactions into large batches before submitting them to the Bitcoin blockchain. This method spreads fixed costs across multiple transactions in each batch, significantly reducing fees for end-users.
What is the Ark protocol?
Ark is a Bitcoin layer-2 that batches many off-chain transactions into a single on-chain settlement. Users don’t open channels (unlike Lightning) — they participate in shared “batch transactions” signed by an Ark operator, get instant confirmation off-chain, and exit unilaterally if the operator disappears. It’s UTXO-shaped, which means it composes with Bitcoin tooling more naturally than account-based L2s.
Where to start
Start with Arkade for the high-level framing, then the Ark protocol intro on ark-protocol.org (maintained by Steven Roose) for the technical specification. The Second protocol docs give an implementation perspective.
This list tracks protocol specs, implementations (Arkade, Second, bark, etc.), wallets, and developer tools.
Protocol
- Arkade - Arkade, A Virtual Execution Layer for Bitcoin-Native Applications by Ark Labs
- Ark protocol - Introduction to Ark maintained by Steven Roose
- Ark protocol intro - Intro to the Ark protocol by Second
Implementations
- Arkade - An Operating System For Programmable Money by Ark Labs
- bark - A Rust implementation of the Ark protocol by Second
Wallets
- Arkade CLI
- A command-line Ark wallet for generating addresses, checking balances, and sending/receiving BTC offchain/onchain from your terminal - btc-wallet-plugin - BTC Wallet Plugin — Arkade MCP Server for AI Agents
- harmoniis-wallet
- Harmoniis Wallet (RGB, Webcash, Bitcoin(ARK), Identities) - arkadeosbot-skill - Claude Code skill for Arkade OS Bitcoin wallet capabilities for AI agents
- artmak
- A Bitcoin Ark wallet implemented as performance art - ark-wallets
- A list of Bitcoin wallets compatible with the Ark protocol - wdk-demo-app
- WDK-based wallet showcasing the official module for Arkade, an open execution engine for Bitcoin.
Explorers
- arkade-explorer
- Arkade blockchain explorer by Ark Labs
Developer resources
Documentation
- Getting started with Arkade - Ark Labs’ how-to for developers
- Getting started with bark - Second’s how-to for developers
- docs-assets - Static HTML assets for Arkade docs
SDKs & Libraries
- ark-ts - Arkade TypeScript SDK by Ark Labs
- ark-go - Arkade GO by Ark Labs
- ark-rs - Arkade Rust SDK by Ark Labs
- ark-dotnet - Arkade C# SDK by Ark Labs
- arkade-assets - Native assets framework for Bitcoin - stablecoins, tokens, and digital assets on Arkade with UTXO-based architecture
- arkade-compiler - High-level language compiler for Arkade Script - write Bitcoin smart contracts in a structured, Ivy-like syntax
- arke - macOS wallet prototype for interacting with Ark protocol (second.tech implementation)
- bark-wallet - bark Rust API reference by Second
- boltz-swap - lightning swaps with boltz for Arkade
- libvpack-rs - Universal verifier and ‘life raft’ for the VTXO (Virtual UTXO) primitive - independent auditability and sovereign recovery across Ark-like implementations
- ark-tx-builder - Deterministic Bitcoin transaction builders for the Ark protocol
- arkade-wdk
- WDK-compatible Bitcoin wallet manager built on Arkade SDK with optional Lightning support via boltz-swap - arkade-kotlin
- Native Android SDK for Arkade - skill
- Arkade skills for AI agent integration — send and receive Bitcoin over Arkade, Lightning Network, and swap for USDC/USDT - asset-demos - Demonstrates how to manage assets across the TS and Golang SDKs
Faucets
- Arkade munitynet faucet - Faucet for mutinynet
- bark signet faucet - Faucet for signet
Projects using Ark
- arkd - Ark Server implementation that powers Arkade
- arkade.money - Web wallt by Ark Labs
- Arkade Wallet - Open-source, self-custodial Bitcoin PWA with native Ark protocol and VTXOs by Ark Labs
- arkade-escrow - Escrow contract demo showcasing trustless escrow functionality on Arkade
- arkash - Supertestnet’s ecash like implementation of Ark
- ark-escrow - 2-of-3 Bitcoin escrow contracts on Arkade
- vtxomarket - Arkade assets marketplace for trading VTXO-based digital assets
- ArkAdmin - Control plane and dashboard for the Bark Bitcoin Wallet Daemon
- Ark Explorer - Explorer and statistics for the Ark protocol by Blockonomics
- btcpay-arkade - BTCPayServer integration for accepting Ark payments
- banco - Non interactive swaps powered by Arkade Script
- insurance-arkade - Insurance contracts built on Arkade
- ln-escrow-ark - Non-custodial Lightning escrow powered by Ark Protocol
- dark - Rust implementation of arkd (Ark protocol server)
- Byte store - Mock online store for testing Ark payments on signet
- coinflip - Coinflip game implemented with Ark
- fulmine - Bitcoin wallet daemon that enables swap providers and payment hubs to optimize Lightning Network channel liquidity while minimizing on-chain fees
- Noah wallet - Mobile-native bitcoin wallet built on Ark
- NArk - Ark payment functionality with BTCPayServer
- snap - Metamask Snap that brings Bitcoin, Lightning and Arkade to your browser
- LendaSat - Bitcoin-backed lending on Arkade (For now only accessible via arkade.money)
- LendaSwap - Cross-chain Atomic Swaps powered by Arkade.
- taproot-assets-in-ark
- Research and integration of Taproot Assets (Taro) into the Ark protocol - emulator
- Introspection is all you need - solver
- Solve intents living in the arkade virtual mempool - arkade-unilateral-exit
- Keyless web executor for Arkade unilateral exit packages - ark-expert
- Claude Code command for answering Ark protocol questions from the public arklabs and second-tech source repos - skills
- Agent skills for Arkade contracts: write with arkadec, spend with the SDK, prove on regtest - delegatee
- Renews Arkade VTXOs and boards bitcoin deposits while the owner is offline - shielded
- Experimental shielded multi-asset Arkade protocol and local end-to-end proof of concept
Blogs
Presentations and podcasts
- Steven Roose on Ark - BitDev conference at Taipei Tech Summit
- Banking on Ark - Banking on Ark talk by Marco Argentieri with slides
- SLP482 Burak – Ark: A new L2 protocol for Bitcoin - Burak on Stephan Livera Podcast
- Ark announcement at Bitcoin 2023 - Burak’s Ark announcement at Bitcoin 2023
- Bitcoin Takeover Podcast S14 E1: Burak Keceli on Ark & Bitcoin 2nd Layers
- The Kevin Rooke Show E109: Burak on Building Ark, Scaling Bitcoin, and Improving Privacy
- The ark-hashed podcast, episode 16
- Updates on Ark development - one year later
- Scaling Bitcoin to 2050 w/ Shinobi, Marco Argentieri, Simanta Gautam & Alex Bosworth
- Transforming Bitcoin: Marco Agentieri’s Vision with Ark Labs
- Ark explained in under 14 minutes
Communites
- Telegram community - Ark protocol Telegram community
- Arkade community - Arkade telegram community
- Second community - Second’s community forum
- Second’s bark chat - Second’s technical support chat, hosted on Zulip
History
Ark v2 reading
- Ark protocol intro - Intro to the Ark protocol by Ark Labs
- Ark deep dive - Original Ark deep dive by Burak
- Introducting Ark v2 - Updated Ark protocol proposal
- Arkade - technical Primer
- Covenant-less Ark
- Unlocking Liquidity Before Shared Output Expiration
- First Ark transaction on mainnet
- Introducing Erk and hArk - new Ark variants
- What’s the opportunity cost of Ark liquidity
- Native Assets on Bitcoin: Introducing Arkade Assets - Framework for bringing stablecoins and digital assets to Bitcoin via Arkade
- Bark’s unified mailbox - New unified notification system for Bark wallets (Feb 2026)
Ark v1 reading
- ARK video from Bitcoin Miami 2023
- ARK presentation from Bitcoin Miami 2023
- [bitcoin-dev] Ark: An Alternative Privacy-preserving Second Layer Solution
- Introducing Ark Blog Post
- Rijndael’s write up on how Ark works
- RubenSomsen’s Simplest Ark Explanation
- Ark Whiteboard Masterclass with Burak & Robin
- Bitcoin magazine: Introducing Ark
- BitGo blog: Will Burak’s Ark Solve Bitcoin Scaling?
- pippellia’s Video Ark Explained - Bitcoin Layer 2 Protocol
Related Resources
To explore other aspects of the Bitcoin and freedom tech ecosystem, check out these additional resource directories:
- nostr.net - A complete guide to Nostr - projects, implementations, developer tools and all other resources
- liquidnetwork.wiki - A curated list of Liquid Network resources, libraries, tools and applications
- pubky.tech - Pubky, an open protocol for censorship resistant web applications
- dlc.wiki - Everything you need to know about Discreet Log Contracts
- ungovernable.tech - A collection of resources on encryption, privacy tools, and decentralized technologies
- lightning-network.tech - Essential tools, guides, and communities for Bitcoin Lightning Network node operators.
- ark-protocol.com - A directory of Ark protocol resources, libraries, tools and applications
Contributing
If you’d like to add something to this list, please submit a Pull Request on GitHub.
This directory is maintained by aljaz. Your contributions help keep this information up-to-date and valuable.