Second, a Bitcoin development lab has officially launched Bark — its implementation of the Ark protocol — on the Bitcoin mainnet, opening up self-deposit bitcoin payments to developers and regular users alike without the complexity traditionally associated with Lightning Network or on-chain transactions.
Bark is built on the Ark protocol, a layer-2 solution that allows large numbers of users to share on-chain UTXOs via trees of pre-signed, off-chain transactions, spreading fee costs across participants while maintaining individual self-sufficiency.
Unlike Lightning, Ark requires no channel management or pre-allocation of liquidity, addressing pain points that have long kept mainstream users tied to custodial alternatives.
“We wanted to make it ridiculously easy for users to get started with self-custodial bitcoin, hold it and spend it without surprise fees and without having to manage channels or liquidity,” CEO Steven Roose wrote in a blog post.
Starting today, Seconds Ark server is publicly available for payments. The launch includes a complete developer toolkit – the Bark SDK – written in Rust with language bindings for Kotlin, Swift, React Native, Flutter, Go, Python and WebAssembly. For server environments, Second also ships Barkd, a standalone wallet daemon that exposes a REST interface with an OpenAPI specification.
Several applications are already mainnet-enabled at launch.
Noah is a full-stack mobile Ark wallet that pairs a React Native frontend with a Rust backend. Arke is a design-led native iOS wallet built around open source UX principles from bitcoin.design. Satsigner brings Sparrow-style UTXO management and multisig workflows to mobile users. Bark Wallet is an Umbrella app that supports Ark, Lightning and on-chain payments.
A BTCPay Server plugin – also built by Second – lets merchants process self-depositing Lightning payments without opening channels or managing liquidity.
Second has raised $5.1 million from a private investor and operates with a team of 11. The company has attracted notable industry talent, including former Blockstream engineers.
The launch comes at a moment of heightened competition in the Bitcoin layer-2 space, with multiple protocols — including Ark Labs’ Arkade and statechain-based solutions — racing to close the gap between self-sufficiency and user experience.
Second will also host a live AMA on Stacker News on June 9 at 10:00 a.m. EST.