News, engineering, and updates from the team building Ark and Lightning payments.https://second.tech/blog/https://second.tech/blog/bark-wallet-now-available-on-start9/https://second.tech/blog/bark-wallet-now-available-on-start9/Bark Wallet is now available on StartOS, and this build ships with something special: continuous encrypted backups...Wed, 29 Jul 2026 00:00:00 GMThttps://second.tech/blog/bark-client-side-pathfinding/https://second.tech/blog/bark-client-side-pathfinding/Up until now, wallet apps built on Bark didn’t handle their own Lightning pathfinding. Instead, the wallet app would send the BOLT11 invoice, amount, and destination to the Ark server, which would...Tue, 21 Jul 2026 00:00:00 GMThttps://second.tech/blog/bark-powers-alby-hub/https://second.tech/blog/bark-powers-alby-hub/Alby Hub lets you connect all your wallet apps to a single payment backend. It takes care of most wallet operations for you, but managing the Lightning node behind it can still be a challenge. Tha...Fri, 12 Jun 2026 00:00:00 GMThttps://second.tech/blog/bark-wallet-now-on-umbrel/https://second.tech/blog/bark-wallet-now-on-umbrel/Bark Wallet hit the Umbrel app store on the same day as our mainnet launch. A number of adventurous users have already installed it and started making payments, and with everything running smoothl...Thu, 11 Jun 2026 00:00:00 GMThttps://second.tech/blog/introducing-noah-and-arke/https://second.tech/blog/introducing-noah-and-arke/We're immensely fortunate and grateful to have had the support of great bitcoin builders even before we launched. They've been building wallet apps alongside our work on the Bark SDK, providing fe...Wed, 10 Jun 2026 00:00:00 GMThttps://second.tech/blog/bark-now-on-bitcoin-mainnet/https://second.tech/blog/bark-now-on-bitcoin-mainnet/The world needs self-custodial bitcoin. But real self-custody is challenging to achieve without compromising on experience. On-chain UX is slow and expensive and prone to spikes of congestion. Tra...Tue, 09 Jun 2026 00:00:00 GMThttps://second.tech/blog/running-barkd-in-a-tee/https://second.tech/blog/running-barkd-in-a-tee/Barkd is what you run when you want to enable bitcoin payments server-side. It's our reference daemon wallet: a single binary that runs alongside your other services and exposes a REST API for send...Thu, 21 May 2026 00:00:00 GMThttps://second.tech/blog/fuzzing-bark-for-server-reliability/https://second.tech/blog/fuzzing-bark-for-server-reliability/Ark users are always in control of their bitcoin. They can perform an emergency exit to get back on-chain whenever they need to. But Bark is a client-server system, and users depend on the server t...Thu, 26 Feb 2026 00:00:00 GMThttps://second.tech/blog/hark-explained/https://second.tech/blog/hark-explained/hArk (hash-lock Ark), first described in a Delving Bitcoin post, and shipped in v0.1.0-beta.6 is an update to our implementation of the Ark protocol that fundamentally changes how rounds are constr...Thu, 12 Feb 2026 00:00:00 GMThttps://second.tech/blog/unified-mailbox/https://second.tech/blog/unified-mailbox/We've redesigned how Bark wallets receive updates from the Ark server. The new unified mailbox gives developers a single, efficient feed for all wallet notifications—Lightning payments, Ark payment...Mon, 09 Feb 2026 00:00:00 GMThttps://second.tech/blog/nested-musig-grant/https://second.tech/blog/nested-musig-grant/We're funding a year-long grant for Beulah Evanjalin to implement nested MuSig in libsecp256k1-zkp. This is a joint effort between Beulah, Second, and Vora, with Jesse Posner providing weekly mento...Thu, 11 Dec 2025 00:00:00 GMThttps://second.tech/blog/diving-deeper-into-lightning-liquidity-amboss-magma-2/https://second.tech/blog/diving-deeper-into-lightning-liquidity-amboss-magma-2/As we continue developing the Ark protocol, understanding liquidity costs has become essential. Our previous research into bitcoin yield products revealed that Lightning liquidity leasing offers so...Thu, 11 Sep 2025 00:00:00 GMThttps://second.tech/blog/survey-of-bitcoin-yield/https://second.tech/blog/survey-of-bitcoin-yield/As we continue the study of Ark’s liquidity requirements, we must come to an understanding on how to price liquidity. Many user operations on Ark require an Ark server to lock up bitcoin (e.g., ref...Mon, 11 Aug 2025 00:00:00 GMThttps://second.tech/blog/ark-liquidity-research-01/https://second.tech/blog/ark-liquidity-research-01/We finally have some research into Ark liquidity requirements that we're ready to share! To explore this topic, we simulated real-world usage for bitcoin users sending Lightning payments. While Ark...Thu, 01 May 2025 00:00:00 GMThttps://second.tech/blog/erk-update/https://second.tech/blog/erk-update/Last weekend at OP_NEXT, we unveiled Erk—a novel variation of the Ark protocol that completely removes the need for user interactivity in rounds. This addresses one of Ark's key limitations: the re...Thu, 17 Apr 2025 00:00:00 GMThttps://second.tech/blog/stephan-livera-podcast-steven-roose-on-ark/https://second.tech/blog/stephan-livera-podcast-steven-roose-on-ark/CEO Steven Roose gave a comprehensive update on the state of the Ark protocol on the Stephan Livera Podcast, so we're sharing the transcript here for those that prefer those! Stephan: Hi everyone,...Mon, 24 Mar 2025 00:00:00 GMThttps://second.tech/blog/try-ark-on-signet/https://second.tech/blog/try-ark-on-signet/Today we're launching our implementation of the Ark protocol on signet. This is our first major step toward bringing Ark to bitcoin mainnet, and we're inviting the developer community to help us te...Wed, 19 Mar 2025 00:00:00 GMThttps://second.tech/blog/the-arkoor-standard/https://second.tech/blog/the-arkoor-standard/We’ve made arkoor the standard for payments on our Ark implementation. Instead of offering users the option of making either out-of-round (arkoor) or in-round payments, all payments will be arkoor...Thu, 12 Dec 2024 00:00:00 GMThttps://second.tech/blog/bitcoin-package-relay-and-ark-protocol/https://second.tech/blog/bitcoin-package-relay-and-ark-protocol/Package relay enables multiple transactions to be packaged, broadcast, and relayed together, and is a huge improvement for layer twos like Lightning and Ark.Wed, 06 Nov 2024 00:00:00 GMThttps://second.tech/blog/demoing-the-first-ark-transactions-on-bitcoin-mainnet/https://second.tech/blog/demoing-the-first-ark-transactions-on-bitcoin-mainnet/We invited some notable bitcoiners and early contributors to the Ark protocol to join us on this adventure. Among the group were Stephan Livera, Marty Bent, John Carvallo, Vivek4real, Jonas Nick, Robin Linus, and Super Testnet.Sat, 21 Sep 2024 00:00:00 GMThttps://second.tech/blog/ark-on-bitcoin-is-here/https://second.tech/blog/ark-on-bitcoin-is-here/Slightly over a year ago, an idea for a new off-chain payment protocol for bitcoin was proposed: Ark. Originally conceived as a solution for onboarding Lightning users, Ark’s design has evolved sig...Mon, 02 Sep 2024 00:00:00 GMT