Building Pesso, neo-bank on stablecoin rails. Leveraging a decade of fintech experience to build a compliant, usable, and composable stablecoin neo-bank.
London
Joined July 2008
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We're building a neo-bank in public, feature by feature. Episode 1: no seed phrase.
Sign in to Pesso with Google or your email and you get a self-custodial dollar wallet. Nothing to write down.
#buildinpublic #fintech
How it works, and an overview of the real architecture 🧵
7/ Why a smart account and not a plain key? Every payment can be batched with its fee, gas is paid in dollars, and the rules live on-chain. That's what will let us give AI agents a wallet with spending limits. More on that soon.
It is incredible the power of motion graphics that frontier models are capable of producing.
I paccked up this skill just for fun.
Just ask Claude Code to ' check this Github repo and help me create an amazing video for [your next feature]: github.com/joanseg/app-previ…
@ClaudeDevs
Joan Senent retweeted
I mapped every crypto card I could find.
And it made one thing painfully obvious:
There is no “best crypto card.”
The answer changes the moment you change countries.
So I built Card Map.
> cardmap.org/
Pick a country and instantly see which cards are actually available there.
Then compare:
> cashback
> fees
> FX
> supported countries
> card tiers
> custody model
> issuers
> rewards
> eligibility
But I didn’t want this to become another crypto card aggregator with a giant table and a fake “Top 10.”
So I kept building. Card Map now includes:
> an interactive global card map
> country-by-country rankings
> detailed card pages
> issuer tracking
> a Card Finder based on what YOU actually need
> a True Cashback Calculator
That last one is probably my favorite. A card can advertise 4%. But after FX, cashback caps, spending bands and a $199 membership fee, your real return might be 2.6%.
Card Map calculates that for you. So instead of asking:
“Which card has the highest cashback?”
You can ask:
“Which card gives ME the best return, in MY country, with MY spending?”
That is the whole idea behind Card Map. Not another directory. A decision tool for crypto cards.
I’m still adding cards, countries, issuers and real-world data every week.
Try it here:
> cardmap.org/
And if something is missing or wrong, send it to me.
I want to map the entire crypto card market.
Your 4% crypto card probably doesn’t pay you 4%.
So I built a calculator that shows what you actually get.
I just shipped the True Cashback Calculator on Card Map.
Try it here:
cardmap.org/calculator
You enter:
> your country
> monthly card spend
> main spending currency
> how much you spend abroad
> whether you’re willing to pay for a tier or lock tokens
Then the calculator does the annoying math for you. Not just the headline cashback rate.
It calculates:
> cashback bands and monthly caps
> FX costs
> annual membership fees
> paid vs token-locked tiers
> blended cashback across your actual spend
> monthly and yearly net return
> what your NEXT dollar of spend earns
And then gives you one number:
Advertised cashback → realistic cashback → actual $ earned after fees.
For example, with $7,650/month on EtherFi Luxe:
3% advertised > 2.78% net > $212.92/month after the annual fee.
You can also switch tiers instantly and compare the same spending profile across cards.
Right now I’ve added:
> @ether_fi
> @Plasma
> @EthenaPay
> @0xinfini
More cards are coming.
I’m tired of crypto card pages screaming “UP TO 8% CASHBACK” while hiding the cap, FX fee, token lock or $1,000 membership behind three different pages of terms.
I want Card Map to answer a much simpler question:
“If I spend MY money with this card, how much do I actually get back?”
And please try to break it.
Send me any card, tier or cashback rule you think the calculator gets wrong.
This is AI agent commerce in practice.
Every Sprintcheckout payment session is now AI Agent ready:
- x402 gives agents a way to pay via API
- no wallet UI
- no account
- no login
- no card private details
- the setup on the agent side: one .env
…(1/2)
linkedin.com/posts/joansenen…
I am a product manager with 10+ years of experience. Started vibecoding with Lovable and Curosr last year. Then moved to Antigravity and Stitch earlier this year. And finally, to Claude Code.
In general found the Vibe coding process very chaotic, do you?
As a result, I built...⬇️
As a result, I built for myself a Claude Code plugin that helps me manage the specs of a new project or a feature on an existing project in an organised way.
It follows pretty much the process I used with engineers and designers. More info: github.com/joanseg/specmanag…
Stablecoins crossed $200B in market cap. Transaction volumes are exploding. But mass adoption? Still missing. The gap is C2M (customer to merchant) payments - real people paying real merchants with stablecoins. That use case doesn't scale globally…
linkedin.com/posts/joansenen…
Payments only evolve when the old system stops working. 👇
- Every major payment innovation came from frustration.
- Cash was inconvenient.
- Checks were slow.
- Cards carried fraud.
- Digital wallets lacked global reach.
Today...