Web3 Devs Underground hosts its monthly meetup on Wednesday, September 23, with this session going deep into Bitcoin multisig from two angles: a hands-on hardware wallet workshop, and a live look inside a multisig product being built in production. Whether you’re securing your own stack or building for others, this one is for you.
In-person & Online
Talk 1 – Sparrow Wallet Multisig Workshop
🎤 Ben Kaufman, Open Source Developer @ Synonym
A hands-on walkthrough of setting up a multisig wallet using Sparrow – including hardware wallet integration, key coordination, and signing flows. You’ll leave knowing exactly how to do this yourself.
- Setting up a multisig quorum from scratch in Sparrow
- Pairing and verifying hardware signers step by step
- Signing flows, PSBT handling, and what to check before funds go in
- Common pitfalls and how to avoid them
Talk 2 – Building summo.cash: A 2-of-3 Multisig App in Production
🎤 Boaz Bechar, Open Source Developer @ papervault.xyz
A look inside summo.cash – a 2-of-3 multisig application actively in development – covering architecture decisions, UX tradeoffs, and what it takes to ship a multisig product users can actually use.
- Hot, warm, and cold wallets – the real differences and what they mean for key management
- Why 2-of-3 and how quorum selection affects your threat model
- Building multisig UX that doesn’t terrify users
- Lessons from shipping a real multisig product
Agenda:
18:00 – 18:30 | Drinks and Networking
18:30 – 18:40 | Opening Remarks
18:40 – 19:25 | Ben Kaufman – Sparrow Wallet Workshop
19:25 – 19:35 | Q&A with Ben
19:35 – 19:45 | Break for Food and Drinks
19:45 – 20:30 | Boaz Bechar – Building summo.cash
20:30 – 20:40 | Q&A with Boaz
20:40 – 21:00 | Finish the evening with us over a beer and some small talk.
Masterkey Venture Capital is a global early-stage fund investing in top-tier innovative deep tech and Web3 infrastructure projects. With a strategic presence in key crypto hubs worldwide, we are uniquely positioned to drive technological advancements within global ecosystems. Backed by nearly 50 years of combined expertise in advanced infrastructure, novel cryptography, cybersecurity, and energy solutions, our team is dedicated to empowering the entrepreneurs shaping the future of blockchain technology.
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Wednesday, September 23, 2026
🕔 Time: 6:00 PM – 9:00 PM IST
📍 Startup Nation Central
Lilienblum St 28, Tel Aviv-Yafo
✨ Web3 Developer Underground Israel is for those who are keen on developing and coding groundbreaking Web3 projects, smart contracts, and exploring the vast capabilities of related technologies.
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