Apr 11, 2023

Quarterly Update Q2 2023

Quarterly Update Q2 2022.

The quarterly blog post bitcoin deserves and needs right now.

🌀 Intro

In February, our team rallied at Bitcoin Park in Nashville, where our lead accused one of this post’s co-authors of stealing La Croix because he doubted whether or not they had the technical chops necessary for the straightforward task of transacting on the Lightning Network. We’ve been called the best team to work for in bitcoin. But now that this anecdote is out there, will people still think so?

While at Bitcoin Park, we met with several co-conspirators from the Bitcoin Development Kit (BDK) team and other FOSS projects. We also deep-dived into technical myopia, went curling, and spoke on a medley of popular bitcoin podcasts.


Last year, when @_tnull joined Spiral, he rudely informed us that “The Lightning Development Kit is great, but it’s quite complex for the average user.” So we let him go (into the woods, not from the team) and started building a solution called LDK Node, a ready-to-go Lightning node implementation that wraps and simplifies the full suite of LDK APIs.

Elias and @ConorOkus revealed a sneak peek at LDK Node during Advancing Bitcoin 2023 in London. By the end of their two-hour workshop, all 30 attendants built a Lightning Wallet from scratch and then successfully paid an invoice. If you missed the workshop, Conor will present it again at Bitcoin++ on Saturday, April 29. More on this honker of an initiative soon.

The newly published LDK roadmap is also making waves. If you don’t feel like reading a 1200-word article about Bolt12, anchor outputs, VSS, simple Taproot channels, and splicing, we invite you to listen to @moneyball dive into these issues during a recently recorded Twitter Spaces.

And there’s more. LDK v0.0.114 went out in March. The release included simpler auto-retries, a crate that keeps LDK in sync with the chain via esplora server routing, performance improvements, @VLSProject security upgrades, etc.


Into the weeds! This quarter’s big Bitcoin Development Kit milestone involved tagging the 1.0 alpha release. The 1.0.0-alpha.0 tag includes the new 1.0 framework and integration testing. APIs and internals are still under active development. As for things that needed maintenance, the 0.27.X branch includes improvements for Fulcrum Electrum server compatibility while fixing public descriptor template key origin paths.

This quarter, projects like bdk-cli and language bindings were pushed forward with fixes and increased exposure to BDK library features. The bdk-cli tool added Hardware Wallet Interface (HWI) support and better messaging that warns users when they forget to sign their PSBTs before broadcasting the transaction.

Further down the rabbit hole, Kotlin, Swift, and Python language bindings can now broadcast raw transactions, create descriptors for BIP44/49/84 templates, access blockchain fee estimation, and see more transaction and address info. The team updated Flutter bindings to the BDK 0.27.1 features and API. Tutorials were added to bitcoindevkit.org along with quick start guides and example apps.

That’s it for the technical stuff. Here’s everything else BDK:

In February, as mentioned above, @afilini, @danielabrozzoni, @thunderB__, and @notmandatory did their own meetup at Bitcoin Park in Nashville, TN, in addition to recording an episode of Citadel Dispatch. Then, on the Builders in Bitcoin podcast, Alekos, and Daniela announced their new hack.bs hacker space in Brescia, Italy. They also teamed up with BitGeneration to bring bitcoin education to Italian high school students via talks and the BDK-based training wallet Padawan. Speaking of, this quarter, Thunderbiscuit listed Padawan on the Google Play store.

Elsewhere in BDK: @RajarshiMaitra hosted a “Mastering Bitcoin’’ cohort through his Bitshala initiative, and @Vlad_kwasi published an article in Forbes about using bitcoin in Africa without Internet access.

🌀 Bitcoin Design Community

The Bitcoin Design Community is among the latest projects in bitcoin to embrace Nostr by adopting Nostr Nests for community calls. They also recently switched from Slack to Discord, though their Slack is still pretty active. Pick one or both and make your own contribution to bitcoin’s future.

Also on planet Nostr, Nostr Hack Week ran from March 8–15. One hundred and thirty-nine people and 51 projects participated. See the pitches here. Still not on Nostr? (Neither are we, but we’re working on it.) Check out Bitcoin Design Community veteran @StephenDeLorme’s talk at Nostrica.

BDC started a new series called Merchant Product Review, which analyzes bitcoin products and tools for merchants. This quarter they went deep on Tiankii, a merchant platform for El Salvadorians, along with the POS terminal functional on Breez. To learn more about how the Bitcoin Design Community approaches user research, watch @MogashniNaidoo’s presentation at FOSDEM, where she discussed the UX Research Kit that she is building with @aassoiants and a few others.

In global Bitcoin Design Community news, the team is organizing an event for Global Accessibility Awareness Day on May 18th. It will be something. There might even be flamingos.

Finally, several members from BDC will be attending BTC Prague. They’ll host an event at Dev Day on June 7th and run a booth at the main expo on June 8-10. If you’re interested in getting involved, please do. They need help in all the ways that people can. Know a solid therapist? Let us know.

🌀 Bitcoin Product Community

Not a lot to say here just yet, but this quarter also saw the launch of the Bitcoin Product Community. This new initiative encourages product managers to shepherd bitcoin projects from the jump to the finish line.

With the help of quite a few others, we did a Twitter Space to announce the community’s formation, what to expect from it, and what PMs can do to get involved with projects right now. As the Q&A section of the Space progressed, we heard something you rarely hear on Twitter: unbridled positivity and enthusiasm.

🌀 New Grants and Renewals

Our grant program is still growing. Know someone with the know-how and ambition to improve bitcoin but without the time and resources to go full-time? Send them our way: grants@spiral.xyz

Here’s who received a grant or had one renewed last quarter.

New grantees:

Renewed grantees:

🌀 Grant Spotlight

The Eye of Satoshi (TEOS)

TEOS is a node-agnostic lightning watchtower implementation that aims to enhance security when using lightning, no matter the node, wallet, or LSP. In addition to having a cool logo, their watchtower is built using LDK. To better understand the implications of that, check out this featured case study by Spiral grantee @sr_gi on the LDK blog.

This quarter, TEOS also released v0.2.0, which is packed with improvements to the tower backend and CoreLN client. Significantly, the tower can now run on top of a pruned Bitcoin Core node, heavily reducing the storage requirements for those who want to spin up an instance (making it more suitable for Raspberry Pis). Regarding the client side, this release improved the UI of the reconnection plugin, sending data to temporarily unreachable towers, and subscription management. In other words, TEOS is now more approachable than a slow golden retriever on a sunny spring day.

Summer of Bitcoin

Bitcoin’s favorite internship program is happening for the third time. The application process is open until April 15th. After that, mentors will evaluate and select students, with the results being announced by the end of April. Since 2021, over 27,000 students from 63 countries have applied to be SoB interns. From them, 124 have contributed to 29 FOSS bitcoin projects sponsored by 60 mentors.


Not long ago, the Fedimint project merged a PR that allows LND nodes to serve as gateways for Fedimint federations. Before the upgrade, only CLN offered gateway support. There is still more work to be done before gateways are production-grade. The team is currently focused on deploying gateway instances on regtest, improving test coverage, and looking for opportunities to simplify architecture and make gateway logic more resilient.

Validating Lightning Signer (VLS)

The VLS team recently released a developer preview (also known as an alpha). While the preview prioritizes security to safeguard against accidental fund loss, its upcoming beta release will strengthen protection against malicious nodes. They invite Lightning developers and enterprises to explore the benefits first-hand. Connect with the team in their Matrix room, submit a feature request, delve into the code, or witness VLS in action with a demo CLN or LDK node.

🌀 Conference and Media Appearances


Product & Design Summit, April 12
Conor Okus will lead a one-day summit at Bitcoin Park along with Stephen DeLorme, @bitkite, and @ODELL.

Bitcoin++, April 28-30
@arikaleph is discussing Lightning on Taproot at 4:30 PM CDT on Saturday, April 29th.

@jkczyz and Conor Okus will lead an LDK Node workshop at 1 PM CDT on Saturday, April 29th.

Bitcoin 2023, May 18-20
@TheBlueMatt and Conor Okus will be speaking at Bitcoin 2023. Details are coming soon.

BTC Prague, June 7-10
Several Spiral members will attend and speak at BTC Prague. Again, details are coming soon.


Contributing to LDK Part 1
Learn how to make your first contribution to LDK with @vallywal. This episode includes peer review, writing documentation, instructions on how to open pull requests, and more.


Bitcoin Core: The Search for Neo
There’s an opportunity for someone to help out with what is without a doubt one of the hardest and least clear roles in bitcoin: PMing Bitcoin Core. If you think you have what it takes to take this on, please check out @moneyball’s recorded Twitter Spaces and tweets about how to get started.

Citadel Dispatch: Lightning Dev Kit
Jeff and Val discussed Lightning wallet trade-offs, mobile wallets, Lightning privacy, BOLT 12, and user-friendly design.

Citadel Dispatch: Spiral Initiatives
Matt Odell and Steve Lee chatted about bitcoin open-source funding, mobile wallets, design improvements, lightning improvements, and BOLT 12.

Builders in Bitcoin: Making Bitcoin Accessible
Conor Okus discussed his bitcoin journey, sustainable open-source development, the importance of easily digestible educational resources for bitcoin newbies, and much more.

Builders in Bitcoin: Facilitating FOSS Development
In this episode, @HBerkoe explained the her goals and responsibilities, the importance of alleviating logistical pressure, how to build community, and so on.

Stephan Livera Podcast: What Bitcoin Specialises In
Matt Corallo discussed bitcoin’s purpose, developments in the space, current and future issues, donations, adversarial environments, soft forks, and LDK.

Bitcoin Review Podcast: Bitcoin Client Building Blocks
Steve Lee and Elias joined Steve Myers, Thunderbiscuit, and NVK to chat about BDK, LDK Node, big items being worked on, and, once again, much more.

See you in three months. If you visit Bitcoin Park, remember to pay for your La Croixs.

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