Picture this

Who it is for

Eight people, fifty dollars a week. Each keeps a jar, their share streams out by the second, the pot fills in public and pays out the moment the round closes. Gaps stay on the record.

Two ways to own it

What you get

Base$299

$75 deposit to reserve

The full app from Terry's Arc portfolio: live surface, contracts on Arc, about page, handover of code and deployment.

You choose: brand name
You choose: accent color
You choose: domain

Customfrom $2,500

Built around you

Reshape it entirely: new features, your flows, your brand end to end, integrations you need. We scope it with you.

Everything in Base
Custom features and design
Priority build

Why it is new

What exists today, and what this does differently

What is new

A rotating savings circle with per second streamed shares was not found.

Closest things out there

WeTrust; off chain esusu apps.

Checked with web searches in October 2026. A search is not proof that nothing similar exists, and the market moves fast, so we recheck before every build.

What it unlocks

The human in it

Built for Arc's sub second, USDC native settlement.

The Regatta Board

Races it can enter

hackathon · Circle · upcoming

Arc / Circle developer programs and hackathons

unknown

Official page ↗

Answers Arc's Request for Builders; check current terms.

Their rule on existing code: unknown

What you own

The whole app, not a starter kit.

The complete Round app: a pardna or savings circle where every member's share streams by the second from their own jar into a public pot that pays the turn holder on the second, with a paywall, keeper agent and gap record built in.

Base price · $299

The user app, complete

Every buyer gets the same finished app. Basic branding and copy changes come through a quick form.

Three step onboardingHome

Shown once: everyone keeps a jar, one pot fills in public, gaps are hours not shame.

Week status and next actionHome

Live pot level, jars on track, rounds closed whole and one clear next step.

Low jar alert with gentle remindersHome

Text reminder for free; reminders in the banker's own voice are gated behind Banker Plus.

Live pot and week simulationPot

Steady week or a jar running dry, per second stream rates, the gap clock and the circle's gap rule.

Payout on the second with receiptPot

Turn holder paid at close, receipt showing what is onchain on Arc and what never is, thank-you and share card.

My jar and top upsMy jar

Balance, runway in hours, top up sheet, payday auto top up and jar history.

Turn calendar and membersCircle

Who has been paid, whose turn it is, every member with their jar level.

Invite to the next cycleCircle

Invite by WhatsApp, SMS or QR; everyone signs to let a new member in.

Swap turns on needCircle

Two members trade weeks with both signatures. Gated behind Banker Plus.

Gap record in hoursCircle

This week's hours streamed for free; the full record of every round is gated behind Banker Plus.

Plans, voice note and settingsMe

Pricing from the owner paywall with USDC checkout, banker voice note recorder, permissions and vision.

Open the full app demo

Add-on

Owner console

Your admin side: revenue, paywall editor, users, rules and the agent log.

Revenue and paywall editorRevenue

Monthly revenue, payout fees, incoming USDC payments, payment methods, live tier names, prices and gates.

Circle rulesRules

Gap rule, buffer size, warning time, payout fee, payout time, voice notes, WhatsApp and gas sponsoring, each changing the week's outcome.

Keeper log and roadmapKeeper

What the keeper did and got wrong, running costs, plus the priced Roadmap.

Top-up

Growth and referrals

Referral and growth mechanics, switched on when you are ready to grow.

Growth loops and cohortsGrowth

Society days, members banking their own circle, public pot link, cohort retention.

Banker to banker referralsGrowth

Referral codes worth a free month for both bankers once a new circle closes round one.

The money path, built in

How it earns for you

Members never pay to save. Bankers pay a small monthly plan for the tools that make running a circle easier, churches and credit unions pay for many circles, and the owner can set an optional small fee on each payout.

MemberFreeYour jar, the live pot, payouts on the second, text reminders, this week's record

Banker Plus$3 a monthVoice note reminders, the full record of every round, swap turns, up to 3 circles

Society$49 a monthUnlimited circles, branded pot pages, Banker Plus for every banker, anonymous stats

Optional payout fee set by the owner (0, 0.5% or 1%), shown on every receipt. Gas on Arc is paid in USDC and can be sponsored by the owner.

Prices are yours to set. Illustrative, not a promise of income.

Growth loops, built in

How it spreads

Members bank their own circle after a full cycle
Hand day share card posted to the family chat
Public pot link anyone can watch fill, without names
Society days that set up circles for a whole congregation
Banker to banker referral codes worth a free month for both

Roadmap · build the next phase with us

Where it goes next

v1 included

The full circle app

Jars that stream by the second into a public pot
Payout on the second with three gap rules
Turn calendar, swaps and invites
Runway warnings and the keeper agent
Receipts, record and share card

Included

Society portal and cash in

Portal for churches and credit unions running many circles
Cash and mobile money top ups through local agents
Branded pot pages per society
Patois and Spanish voice prompts

Add-on from $500

Diaspora circles and a portable record

Members in Kingston, London and Toronto in one circle
USDC in, local currency out at payout
A member-owned record of rounds kept whole
Open circle contract others can audit

Add-on from $1,200

For investors and grant reviewers

The pitch, ready

A savings circle that runs itself: shares stream by the second into a public pot that pays whoever's turn it is, on the second.

Problem: Hundreds of millions of people save through rotating circles like pardna, susu and tanda. They run on one tired banker with an exercise book: cash in envelopes, chasing late members, covering gaps from their own purse, and no shared record.

Solution: Each member keeps a jar that streams their share into one public pot on Arc. A keeper warns low jars in the banker's own voice, closes the round at the agreed second and records gaps in hours, never reasons.

Why now: Arc settles in USDC with sub second finality and USDC as gas, passkey wallets work for people with no crypto experience, and small models can write warm reminders for cents.

Market: Circle bankers and members across the Caribbean, Africa, Latin America and their diasporas, plus the churches, credit unions and societies that host many circles.

The ask: Pilot partners: one church or credit union with 10 circles, and builder support from the Arc and Circle developer programs.

Funding is never guaranteed. Check each program's rules.

For hackathons and demo days

Your 2 minute demo

Home: meet Miss Pauline, 58, banker of a pardna in Kingston for twenty years. Kemar's jar is running low.
Pot: play the week. Kemar runs dry Wednesday, gets a warning, and tops up Thursday.
Pot: Sunday 6 PM the pot pays Dwayne on the second; show the receipt and send the thank-you.
Circle: the turn calendar and the gap record in hours; swaps and the full record unlock with Banker Plus.
Me: open Plans and upgrade through the USDC checkout, then record the voice note.
Owner Rules: change the gap rule, buffer and warning time and watch Dwayne's payout change.
Owner Keeper: the wrong payday guess and how it adapted.
Owner Revenue and Roadmap: edit the Banker Plus price, then request the v2 society portal.

Many hackathons require code written at the event. See the Regatta Boardfor each race's rule.

Make it entirely yours

Custom work from $2,500: your own circle rules and statements, mobile money or bank integrations, extra languages and voice prompts, or a society branded deployment. Scoped on a call.

Custom from $2,500

BLUEPRINT

Why it matters and how it really works

The need

Hundreds of millions of people save through rotating circles (pardna, susu, esusu, tanda, chit funds). They run on trust and one tired banker with an exercise book: cash in envelopes, chasing late members, covering gaps from their own purse, and no shared record when memories differ.

What exists and what is new

Rotating savings circles are old and already digital in places: WeTrust tried onchain circles years ago, and many offchain esusu and tanda apps collect contributions by card or mobile money. What we did not find is a circle where each member's share streams by the second from their own jar into a public pot that pays out at the exact close, with gaps recorded in hours. Novelty is medium: the circle is familiar, the streaming mechanics and the plain gap record are the new part.

The data it runs on

Circle rules (members' wallet addresses, hand amount, order, gap rule), per-second stream rates, jar balances, payouts and gap records in hours. Names, phone numbers, voice notes and reasons for lateness stay offchain with the banker.

1.The mission

Give every savings circle a pot that pays on time and a record everyone can trust, so the banker never has to chase or cover again.

2.Why people can't resist it

Watch the pot fill The pot rises all week in public. Seeing it nearly full by Saturday is the reason people open the app.

Paid on the second Hand day is a moment: the payout lands at 6:00:00 PM Sunday and everyone sees it.

No shame, just hours Gaps show as hours and whether they were made whole, never reasons or scores, so people stay in.

3.How it works for real

Wallets: Privy embedded wallets with passkeys so members without crypto experience get a jar; optional fiat onramp to buy USDC.

Circle contract on Arc: One contract per circle on Arc, where USDC is the gas token: members, hand, order, gap rule and buffer percentage, set at creation and changeable only with every member's signature.

Streams: Each jar streams to the pot at hand divided by seconds in the round. Balances are computed lazily (rate times elapsed time), so no transaction is needed per second.

Close and payout: A keeper calls close at the round end; the contract settles streams, applies the gap rule and pays the turn holder in one transaction.

Keeper agent: A small model (Claude Haiku class via OpenRouter) writes warm reminders from runway data; the runway maths and all money movement are plain code. It cannot move funds.

Notifications: WhatsApp Business API or SMS for runway warnings and hand day, with a voice note recorded once by the banker.

Indexer: Convex indexes contract events for the pot view, turn calendar and record.

4.Cost per use and pricing

Arc is new and fee levels can change, so check current fees before launch. Per circle per week: one close and payout transaction plus occasional top ups, expected to cost cents in USDC. Reminder text from a small model is well under one cent each. Messaging costs depend on the provider and country, roughly 1 to 5 cents per WhatsApp or SMS. Example: 100 circles of 8, weekly, about $20 to $60 a month in messaging and gas.

Circle Free

One circle up to 8 members, weekly rounds, SMS reminders.

Banker $4 a month

Up to 5 circles, voice note reminders, buffer rule, printable record.

Community $29 a month

Churches, co-ops and unions running many circles, with an admin view and exports.

5.Growth loop

Each circle has 6 to 12 members, and members often bank their own circle next. The share card from hand day and the public pot link are the invitation.

6.Risks and guardrails

Regulation: Pooling and paying out money may count as a regulated savings or remittance activity in some countries. Get local advice; the owner never holds member funds.

Default after payout: A member who received the pot early can stop paying. Streams make this visible fast but cannot prevent it. Order rules and small buffers reduce harm; say this plainly at setup.

Stablecoin and chain risk: USDC and Arc carry issuer and network risk. Arc is young; keep circles small at first.

Privacy: Wallet activity is public. Keep names offchain and avoid linking addresses to identities in the public view.

Smart contract bugs: Audit the circle contract, cap circle size and value early, and include a unanimous-exit path.

7.Build order

Circle contract with fixed order and the three gap rules on Arc testnet
Privy wallets and a jar top up screen
Pot view with lazily computed stream balances
Keeper that closes rounds and pays out
Runway warnings by SMS, then WhatsApp voice notes
Turn calendar, record view and share card

8.Where this is going

Now
One banker in Kingston runs her pardna without envelopes or chasing.
Next
Churches, markets and unions run dozens of circles with one admin view.
Later
A member's long record of whole rounds becomes proof of reliability they can choose to share.
The big one
The world's oldest way of saving gets the same on-time, transparent rails as any bank, owned by the people in the circle.

Costs and tools are estimates at the time of writing. General information only, not legal or financial advice.

OWNER PLAYBOOK

Own it, then chart your voyage

Nine routes from one vessel. Tap a port to open its chart.

Why own Round

Round: A savings circle that runs itself: shares stream by the second into a pot that pays whoever's turn it is. Using someone else's version means their rules, their brand and their revenue. Owning Round means it is deployed under your wallet, carries your name, and every customer, partner and result builds your track record instead of theirs.