What Settld is

Settld is a shared expense app. Split a dinner, a trip, or a bill with friends. Except instead of just calculating who owes what, it actually moves the money. When you tap "Settle up," a real transfer of digital dollars (USD₮) leaves your wallet and lands in your friend's, in seconds, verifiable on a public blockchain. The user never has to know that's what's happening. The whole app talks in plain words: balance, add money, pay, settle up.

## How the product works, end to end

1. Signing up. The moment you create an account, the browser silently generates a real crypto wallet via Tether's WDK. You pick a username and password like any app. Under the hood, that password encrypts your wallet's private key on your own device before anything touches our server. We only ever receive the encrypted blob, never the key itself. That's what makes it self custodial: even we can't move your money.
2. Adding money. Three ways, none of them mention crypto: buy with a card using MoonPay, show a QR code so someone pays you, or grab test funds for the demo.
3. Creating a "settld." This is the core object. There are no groups. A settld is just what you paid for, how much, and who it's split with by @username. You type it in, the per person share updates live, done. Whoever paid owns it and is the only one who can edit or delete it.
4. The dashboard. Shows three real numbers: what you can spend, read live from the blockchain, what you owe, and what you're owed. The debts are netted person by person. If you owe your friend $18 and they owe you $22.50 from something else, it collapses into one row: they owe you $4.50.
5. Settling up. Before anything is signed, you see a full preview with the exact amount, network fee, and balance after. Confirm, and WDK executes a real USD₮ transfer on Ethereum Sepolia. You get a receipt with a transaction hash linked to a public block explorer, proof it actually happened.

How it works technically

No one needs a second currency for gas. Normal crypto wallets need ETH just to pay network fees, which is a dealbreaker for a normal user. Settld uses account abstraction (ERC 4337) with a paymaster, so network fees are paid in the same USDt being sent. One currency, start to finish.

Payment confirmation doesn't trust the flakiest piece of infrastructure. The public bundler that submits transactions is rate limited and sometimes refuses calls mid demo. Instead of asking it "did this work?", Settld reads the event the blockchain itself emits when a transaction lands, the actual source of truth. A failed pricing call before anything is signed gets retried automatically. A transaction that's already been sent is never retried, because that could pay someone twice, and it's never shown as "failed," only "pending," since once money is on its way, it's on its way.

The math is pairwise, not group wide, on purpose. With old style "groups," everyone in a group sees the same expenses, so you can optimize "who pays whom" across the whole group. Without groups, there's no shared set. Someone you split a dinner with is in other settlds you can't see. So a debt only ever exists between two people, computed from everything between just the two of you, and both people see the exact same number.

Deleting a settld doesn't touch payments. If money already moved on chain, that's a fact. Deleting the settld that caused it doesn't undo it. The math just shows the payer owing it back.

That's the whole loop: real wallet, real transfer, real receipt, zero crypto vocabulary anywhere a user can see it.