Multisig in Practice | Sparrow Workshop + Building summo.cash
โWeb3 Devs Underground - Monthly Meetup ๐ Multisig in Practice | Sparrow Workshop + Building summo.cash
โYour keys. Your coins. But can you actually prove it - and ship it?
โThis session goes 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.
โ๐ Brought to you by Israel Web3 Developers Underground ร Startup Nation Central
โPowered by Masterkey VC
โDate & Time
โ๐ Wednesday, September 23rd, 2026
โTime: 18:00 - 21:00
โLocation:
โStartup Nation Central, Tel Aviv
โSpeakers
โTalk 1 - "Sparrow Wallet Multisig Workshop"
โ๐ค Ben Kaufman, Open Source Developer @ Synonym
โA 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.
โSetting up a multisig quorum from scratch in Sparrow
โPairing and verifying hardware signers step by step
โSigning flows, PSBT handling, and what to check before funds go in
โCommon pitfalls and how to avoid them
โTalk 2 - "Building summo.cash: A 2-of-3 Multisig App in Production"
โ๐ค Boaz Bechar, Open Source Developer @ papervault.xyz
โA 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.
โHot, warm, and cold wallets - the real differences and what they mean for key management
โWhy 2-of-3 and how quorum selection affects your threat model
โBuilding multisig UX that doesn't terrify users
โLessons from shipping a real multisig product
โAgenda:
โ18:00 - 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.
โAbout Our Sponsor:
โMasterkey 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.
โGet Involved
โInterested in Speaking or Sponsoring?
โWe welcome passionate individuals and organizations to contribute to our community. If you're interested in speaking at future events or sponsoring our meetups, please fill out the Speaker application form and contact Amit Shilo at @Amit_Shilo (Telegram)
โCommunity Team: Amit Shilo, Eden Luttenberg, Alon Kivity, Alon Ben Lavy, Ariel Wagowsky, David Langellotti, Boaz Bechar, Daria Nik.
โFounded by Shauli Rejwan and Roy Osherove.
โRSVP Now!
โJoin the Israeli branch.
โLimited seats are available. Register early to ensure your participation!
โStay Connected
โStay in the loop (socials):
โTwitter โ /Web3_Devs
โYouTube โ https://www.youtube.com/@web3devsunderground/streams
โCalendar โ https://lu.ma/web3devs_underground
โSee You There!