Designing digital cash: a year with the Bitcoin Design Guide.
We joined the Bitcoin Design Community, studied its open-source Guide, and built a pay-in-sats prototype at a global Lightning hackathon, to learn how you design money that nobody is in charge of.
In 2022 we went back to school. Invisible Building joined the Bitcoin Design Community, studied the open-source Bitcoin Design Guide in depth, and built a pay-in-sats prototype at a global Lightning hackathon. The aim was to learn, properly, how you design money that nobody is in charge of.
This was research, not client work, and we want to be precise about it. The Guide is written by its community. We are students of it rather than authors, and nobody funded us to study it. What follows is what we learned and what it changed about how we design.
- What
- Self-directed R&D in bitcoin, Lightning and wallet design
- Source
- The Bitcoin Design Guide, free and open source
- Community
- Bitcoin Design Community, kick-started by Square Crypto (now Spiral) in summer 2020
- When
- 2022, alongside our own fintech, Sugar
- Built
- PayMyDesk: hot-desking paid for in sats, at Shock the Web, March 2022
- Used for
- Sugar, and how we approach checkout, onboarding and payment flows
Cash is disappearing. What replaces it is a design question.
We were building a fintech of our own, and the more time we spent with payments the clearer it became that the interesting problems were not technical. A society that stops using cash hands a great deal to whoever runs the replacement: who can be paid, who can be frozen out, what it costs to be poor. A fairer version of digital cash is possible. Whether ordinary people can actually use it is down to design.
Bitcoin is the hardest version of that problem. There is no bank to ring, no “forgot password”, no one to reverse a mistake. If a designer can make that safe and understandable for someone who has never heard the word “seed phrase”, everything else in fintech is easy by comparison. So that is where we went to learn.
Why add a designer into the mix? I believe this is an underfunded area in the crypto ecosystem. Great design will help more people access this technology faster and better.
Jack Dorsey, March 2019, on why Square’s new crypto team would include a designer
An open-source design school for money.
In June 2020 Square Crypto, the bitcoin-focused open-source initiative of Jack Dorsey’s Square, decided that instead of hiring one full-time designer it would help start a community of them. In its own words: “Square Crypto will use our platform to direct talent to this community, but we won’t run it.” It backed that with grants to individual designers, and the Bitcoin Design Community grew from there.
The community published the first version of the Bitcoin Design Guide on 2 June 2021, and a major revision focused on the Lightning Network on 9 February 2022. By then it described itself as “an open group of over 2,400 product designers, developers, and creatives”. Square became Block in December 2021 and Square Crypto became Spiral, which still lists the community among the projects it has funded through grants. All of the Guide’s content lives on GitHub under open licences; anyone can read it, use it and contribute.
That is the extent of the connection, and it is worth saying plainly: Spiral and Block supported the Guide and its community, not us. We turned up, read everything and did the homework.
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Square Crypto announces support for a decentralised bitcoin design community, and grants for designers.
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The community launches the first public version of the Bitcoin Design Guide.
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Square becomes Block; Square Crypto becomes Spiral.
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Guide V2 lands, refocused on mobile-first, non-custodial Lightning wallets.
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We build PayMyDesk at BOLT.FUN’s Shock the Web hackathon; the community reviews it on a call the day after the hackathon closes.
Seven principles we took with us
The Guide’s design principles, in its own words. Swap “bitcoin” for “your product” and most of them still hold.
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Self-custody
“Let users control their private keys, with no risk for seizure or freezing of funds.”
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Security
“Provide appropriate and progressive security for all types of users.”
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Inclusion
“Build borderless products without location, language or social barriers.”
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Interoperability
“Enable import and export of wallet data, maximize backwards compatibility, and use open standards.”
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Transparency
“Be open and transparent with how your product works, open-source your code when possible.”
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Privacy
“Minimize collection of personal information, and maximize financial transaction privacy.”
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Decentralization
“Design products that encourage people to run a full bitcoin node.”
Four problems every wallet has to solve.
Keys: safe enough, easy enough
The Guide puts the whole trade-off in one sentence: “if your application is not secure enough, you risk losing the user’s funds. But if it’s not convenient enough, you risk losing the user.” Its answer is progressive security: start people with something simple like an automatic cloud backup, and introduce stronger options as the amount they hold grows.
Onboarding without the jargon
Seed phrases, XPUBs and mnemonics are how engineers talk. The Guide tells designers to keep those terms away from new users and to explain what is happening in plain language at the moment it matters. We had already learned that rule building FixIT for families who could not read the labels at all.
Units and symbols
“Bitcoin, bits, sats. The format and presentation of bitcoin values are probably amongst the most challenging for application builders.” One bitcoin is 100 million satoshis, so a coffee is either ₿0.00005 or 5,000 sats, and the choice changes how expensive it feels. It is a typography problem, a maths problem and a psychology problem in one label.
Asking to be paid
A Lightning invoice carries an amount, a destination and an optional message, and by default it expires after 60 minutes. Designing a “pay me” screen means designing for the scan that fails, the invoice that lapses and the person who has never seen a QR code used for money.
PayMyDesk: rent a desk, pay in sats.
Reading only gets you so far. In March 2022 we entered Shock the Web, the first hackathon from Peak Shift’s BOLT.FUN. It was a week-long online Lightning Network event, open to anyone, from 22 to 28 March, supported by Bitcoin Design, Spiral, Alby, LNbits and Galoy. Three days of talks were followed by a three-day build sprint. Christoph Ono of Bitcoin Design gave the introduction to the Guide and its UI kit.
As Team Sugar we built PayMyDesk, “the Airbnb of desk renting” and the first thing we had ever made with bitcoin. List a spare desk, set your own day rate in sats, and the renter scans a Lightning QR code to book it. True to form it was mostly no-code: the LNbits API for payments, Airtable for the desks, Zapier to join them up and a Ghost site on the front. The domain was registered on the second day of the sprint. The top prizes went to Arion Parking, LNbits Legend and TwentyUno. Ours came the following evening, when the Bitcoin Design Community made PayMyDesk the subject of its “Learning Bitcoin and Design” call: an hour of open critique from people who design wallets for a living.
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paymydesk.com on demo day, 28 March 2022. -
The first sketch: a QR code on the desk, an invoice when it is scanned, sats to the right people for the hours used. -
Booking Desk 002 at “Satoshi’s”: scan the LNURL code with a Lightning wallet.
Better at money. Better at everything else.
The year fed straight into Sugar, and into the Future of Fintech panel David joined at Digital DNA. The lessons travel well beyond bitcoin. Progressive security is the right way to think about account creation on a Shopify store. “Explain it at the moment it matters” is the right way to write checkout copy. And a community that does its design reviews in public, on a call anyone can join, is the best model of open critique we have come across.
We are designers and builders, not evangelists, and we have no coin to sell you. If you are building with payments, wallets or any technology your customers don’t yet have a mental model for, have a look at our consultancy for startups or get in touch.
Notes from the year
Written up from our notes and the public record, and dated to when it happened.
PayMyDesk: What We Built at the Shock the Web Lightning Hackathon
We built PayMyDesk, hot-desking paid for in sats, at BOLT.FUN’s Shock the Web Lightning hackathon in March 2022.
Design on Hard Mode: Notes from the Bitcoin Design Guide
The Bitcoin Design Guide went Lightning-first in February 2022. What it teaches about keys, progressive security, jargon and units.