Second

@second.tech

Simple developer solutions for integrating fast, low-cost, self-custodial bitcoin payments into your apps. Supports Lightning, Ark, and on-chain.

1/ Two releases in two days...we hope you'll understand given the emerging security environment in bitcoin. 0.6.0 has some breaking changes you're going to want to pay attention to, please get updated asap. And thanks to @bonomat of Lendasat for the report behind a fix.

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1/ Bark 0.5.0 is out, and it comes with one of the features you've asked for most: restoring a wallet's full off-chain balance from its mnemonic.

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1/ We got a lot of requests for Bark Wallet on Start9 after launching on Umbrel last month. Well, here it is: Bark Wallet is now available on the Start9 Registry!

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1/ Wallet apps built on Bark have never done their own Lightning pathfinding: the Ark server works out the best path on their behalf. It works great, but some users want more control, or don't want to share destination data. New research from grubles explores an alternative.

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1/ Bark 0.4.0 is out, and receiving just got simpler. One BIP 321 payment request now covers Ark, Lightning, and on-chain: build it in one barkd call or straight from the SDK, and the payer's wallet app picks whichever rail it speaks.

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1/ Since launching on mainnet, we've been hard at work refining Bark's DX and UX, guided by the quality feedback we've been getting from integrators and users. Here are the best bits from releases 0.2.3 to 0.3.0.

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1/ Bark is now a Lightning backend option in Alby Hub. Alby built the integration on the Bark SDK in record time, just days after our mainnet launch. You can now enable Lightning payments in your hub with no Lightning node, channels, or liquidity to manage.

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1/ Bark Wallet is now on the Umbrel app store. A number of adventurous users have already been installing the app and making payments, and with everything running smoothly, it's time for a proper introduction.

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1/ Bark went live with wallet apps ready to go on day one, built by bitcoiners who've been working alongside us since long before launch. Today we're showcasing the two most polished so far: Noah and Arké 🧵

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SECOND IS NOW ON MAINNET. Bark, our implementation of the Ark protocol, is available for anyone to start making bitcoin payments. Included in the launch are our mainnet Ark server, the Bark SDK, and multiple wallets to try from day one.

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1/ Hot on the heels of 0.2.1, Bark 0.2.2 is out, making Lightning sends crash safe. Outgoing LN payments are now checkpointed, so no more stuck balances after a mid-send failure. And settled invoices are recorded for good: your wallet won't ever attempt the same payment twice.

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1/ Changelog catch-up. We're covering the best bits from three recent releases: 0.1.4, 0.2.0, and 0.2.1. First up, slim VTXO storage. Bark now keeps each VTXO in a slim "bare" form—around 200 bytes per VTXO, a 20–100x cut in memory for wallets with many or deep VTXOs.

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Nested MuSig2 now has a Python reference implementation. Beulah Evanjalin built it on secp256k1lab with tests, examples, and protocol notes—generally in a good state for review and discussion. This is the blueprint that will inform the secp256k1-based C work.

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1/ Barkd is what you run when you want to enable bitcoin payments server-side. On a standard cloud VM, the provider, hypervisor, and co-tenants can theoretically read your signing keys from memory. We decided to run some tests to see if TEEs were the solution.

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New page up: a directory of wallets building on Bark. Most are open source, so you can see how teams are handling the Bark SDK and Barkd to deliver bitcoin payments over Lightning, Ark, and on-chain.

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1/ Small but mighty changelog for 0.1.3. Bark now ships an IndexedDB StorageAdaptor—the missing piece for browser-based wallets. Combined with the WASM and gRPC-web support from 0.1.0, you can now build Ark wallets that run entirely in the browser with persistent state.

Byte in the browser

𝟭/ Here's a double changelog for Bark 0.1.0-beta9 and 0.1.0 (you know we’re getting closer to mainnet when the “beta” tag is dropped!)...

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Nice one AJ Towns. Your signet reorg simulations caught a nasty bug lurking in unusually deep reorgs. Thank you for passively torturing our code with edge cases 👍

"This was a genuinely fun build. The Bark integration was way smoother than I expected going in. Being able to accept Lightning payments without running my own node, and having native Ark payments work alongside that, made the whole payment layer surprisingly simple to wire up." - PiHiker, ArkAPI

We've integrated Lightning natively across the Bark protocol, wallet, and server. We're as much a Lightning startup as we are an Ark startup.

Our technical docs just got a whole lot better. New platform, getting started guides for Rust, Go, React Native, and more, an API reference, and possibly the most comprehensive explanations on protocol mechanics for any bitcoin layer 2 out there.

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1/ Changelog time. Beta.8 is out. Bark servers now support fees across all major operations—boards, refreshes, and Ark/Lightning/on-chain payments. And yes that means the Second server now has a fee schedule defined in prep for our mainnet launch.

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Christoph Ono's Arké wallet keeps getting better. This is what happens when you unleash a designer armed with agents and the Bark SDK.

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Bark makes it ridiculously easy to build bitcoin wallet apps that supports on-chain, Lightning, and Ark payments. All self-custodial.

Bark bindings now ship with every release, published to package managers automatically—pre-built binaries, no cloning repos, no local builds, no Rust toolchain. Just add the dependency the way you already do for everything else.

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1/ We caught a capacity overflow bug in Bark before it ever hit a user, thanks to the fuzz testing @luca0x46 has been running around the clock. A malformed VTXO could have requested an arbitrary vec size during deserialization, triggering a panic. Now it's patched.

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