Rota ◎ — Global Group Savings & Rotating Credit on Arc

rota (Latin): wheel. Your turn always comes.

The world has always saved in circles — somiti (Bangladesh), chit fund/kameti (India, Pakistan), tanda (Mexico), susu (Ghana, Caribbean), esusu/ajo (Nigeria), hui (China), paluwagan (Philippines), gam'eya (Egypt). Rota puts them all on one set of rails: smart-contract escrowed savings circles in USDC on Arc, Circle's stablecoin-native L1.

Beachhead market: Bangladesh — complete Bangla UI, taka amounts on every screen, somiti-native copy, and diaspora corridors (Dubai/KSA/Malaysia/UK/US → Dhaka). New markets are configuration, not refactoring (see Adding a locale/currency).

Products

Product	What it is
Rota Circle	Classic ROSCA: N members pay a fixed USDC amount per round; each round one member takes the whole pot (fixed or random order).
Bid Circle	Chit-fund mode: members who haven't won bid a discount to take the pot early; the discount is redistributed to everyone as a dividend — a market price for liquidity.
Goal Pot	Non-rotating group saving toward a target (wedding, tuition, Eid, land). Locks until target/deadline; everyone withdraws exactly their own deposits.

Cross-cutting: contract escrow (no absconding organizer), deterministic payouts, collateral + default curing, non-custodial AutoPay, optional Giving round (labeled Zakat/Sadaqah in bn/ur), and an on-chain Credit Passport reputation score for thin-file users.

Repository layout

rota/
├── contracts/            Foundry project (Solidity 0.8.24, OpenZeppelin 5)
│   ├── src/              RotaFactory, RotaCircle, GoalPot, ReputationRegistry
│   ├── test/             66 tests: happy paths, bids, autopay, defaults, fuzz, invariants, reentrancy
│   └── script/           DeployLocal / DeployArc (+ script/config/ArcConfig.sol)
├── app/                  Vite + React 18 + TS + Tailwind + wagmi v2/viem + i18next
│   └── src/
│       ├── config/       chain.ts (single source of chain truth), currencies.ts
│       ├── abi/          AUTO-GENERATED by scripts/abi-sync.mjs
│       └── i18n/         en + bn complete; es/hi/ur/tl scaffolds
├── genlayer/             news_curator.py — GenLayer Intelligent Contract (AI news desk)
├── scripts/              abi-sync.mjs, seed-local.mjs
├── docs/                 ARC_NOTES.md (researched chain values), DECISIONS.md, ROADMAP.md
└── SECURITY.md           honest limitations — read it

Prerequisites

• Foundry (forge, anvil)
• Node ≥ 20, pnpm
• A browser wallet (MetaMask) for the UI

Quickstart (local)

pnpm install

# terminal 1 — local chain
pnpm chain

# terminal 2 — deploy + wire the app + demo data
pnpm deploy:local     # MockUSDC + registry + implementations + factory,
                      # writes app/src/config/deployments.local.json, syncs ABIs
pnpm seed:local       # demo: ROSCA with 2 rounds played, bid circle mid-auction,
                      # goal pot at 60% — instantly demo-able
pnpm dev              # app at http://localhost:5173

In MetaMask: add network http://127.0.0.1:8545 (chain id 31337) and import anvil account #0 (0xac09…ff80 private key printed by anvil). Accounts #0–#3 are members of the seeded circles. The header has a Mint 1,000 test USDC button on anvil.

Run the contract suite:

pnpm test:contracts    # forge test — 74 tests, all green

Arc testnet — live deployment

Rota is deployed on Arc Testnet (chain id 5042002, redeployed 2026-07-12 with the audit fixes from SECURITY.md):

Contract	Address
RotaFactory	0x1ba8Aabc9501d6C68A9eE1387b0d40d53EdCC325
ReputationRegistry	0xDE51D720ad3b93300e6f8A6F936f62F291c5CE80
RotaCircle implementation	0x5d5f658706acCB2B25B7f3FE22261C44DCA0DC2F
GoalPot implementation	0x0159536F931Ed1d1DdFEB4f1fc69F9f8429f0161
USDC (canonical ERC-20 interface)	0x3600000000000000000000000000000000000000

Run the app against it with VITE_CHAIN=arc pnpm dev (or set VITE_CHAIN=arc in .env / .env.local at the repo root — the app reads env from there). Get testnet USDC for your wallet at https://faucet.circle.com (Arc Testnet); on Arc, USDC is also the gas token.

News page — AI curation via GenLayer

The /news page shows the best Arc-ecosystem news and stories from Rota's domain (ROSCAs, group savings, stablecoin remittances), curated on-chain by a GenLayer Intelligent Contract (genlayer/news_curator.py) on the GenLayer Studio testnet: on each refresh_news() call, validators fetch live news feeds, run an LLM curation prompt, reach consensus, and store the result as JSON. The app reads it with genlayer-js — no backend, no API keys.

A curator instance is live on GenLayer studionet:

Contract	Network	Address
RotaNewsCurator (Intelligent Contract)	GenLayer studionet	0xDFEE06117b8d91b5b3e17Bfb09C6C0592ea71690

To run your own instance, deploy news_curator.py at https://studio.genlayer.com and set VITE_GENLAYER_NEWS_CONTRACT=0x… in .env.local (see genlayer/README.md). When unset, /news shows setup instructions instead. Note: studionet resets occasionally — if reads fail, redeploy and update the address.

Redeploying

Chain values were researched from docs.arc.io and recorded in docs/ARC_NOTES.md: chain id 5042002, RPC https://rpc.testnet.arc.network, explorer https://testnet.arcscan.app, USDC = native gas token with an ERC-20 interface at 0x3600…0000 (6 decimals).

1. Fund a deployer wallet with testnet USDC at https://faucet.circle.com (a full deploy costs ≈ 0.12 USDC in gas).
2. cp .env.example .env and set PRIVATE_KEY=0x… (the 0x prefix is required).

3. pnpm deploy:arc   # sources .env/.env.local, deploys registry/implementations/factory,
                     # writes contracts/deployments/arc.json, syncs ABIs + addresses to the app

Architecture

RotaCircle state machine

stateDiagram-v2
    [*] --> OPEN: factory.createCircle (organizer auto-joins)
    OPEN --> OPEN: join() — collateral escrowed
    OPEN --> ACTIVE: activate() when full (payout order fixed/shuffled)
    OPEN --> CANCELLED: cancel() by organizer, or anyone after openDeadline
    ACTIVE --> ACTIVE: contribute()/pullContribution() → placeBid() [BID] → settleRound()
    ACTIVE --> COMPLETED: settleRound() of round N
    COMPLETED --> [*]: withdrawCollateral(), withdrawDividends()
    CANCELLED --> [*]: withdrawCollateral()

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Per active round: members contribute before the schedule-anchored deadline (AutoPay lets anyone trigger an opted-in member's exact contribution); in BID mode an auction runs during the first bidWindowBps of the round; settleRound() slashes defaulter collateral, pays the optional giving cut, pays the recipient (order-based or winning bidder minus discount), credits bid dividends pull-withdrawably, and reports everything to the ReputationRegistry.

GoalPot state machine

stateDiagram-v2
    [*] --> LOCKED: factory.createGoalPot
    LOCKED --> LOCKED: deposit() (join on first deposit)
    LOCKED --> LOCKED: emergencyWithdraw() — haircut shared with stayers
    LOCKED --> UNLOCKED: unlock() when total ≥ target OR now > deadline
    UNLOCKED --> [*]: withdraw() — exact principal + haircut share − giving cut

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Reputation

Only factory-deployed clones can write. Transparent score: completions×100 + contributions×10 + cures×20 − defaults×50 − earlyExits×15 (floored at 0). The frontend renders a shareable Credit Passport page per address with QR, history, and client-side signature verification — no backend.

Feature matrix

The phased plan behind the “Future” column lives in docs/ROADMAP.md.

Feature	MVP	Future
ROSCA / bid / goal-pot products	✅
Collateral, default slashing, curing	✅	multi-round collateral
Non-custodial AutoPay	✅	protocol keeper network
Giving round (Zakat/Sadaqah)	✅
Reputation registry + passport page	✅	soul-bound token passport
en + bn locales, 7 display currencies	✅	es/hi/ur/tl translations
In-app + browser deadline reminders	✅	Telegram/WhatsApp bots
Random order via blockhash	✅ (documented)	Chainlink VRF
Local anvil + Arc testnet	✅	mainnet (post-audit, post-legal)
Fiat ramps (bKash/Nagad, UPI, M-Pesa, GCash)	—	per-market integrations
Arc App Kit Unified Balance / Bridge deposits	—	chain-abstracted funding
Emergency micro-advances against reputation	—	research
AI organizer agent, mobile app	—	research

Adding a locale/currency

New markets are pure configuration:

1. Locale: copy app/src/i18n/en.json to <code>.json, translate every key, register it in app/src/i18n/index.ts (SUPPORTED_LOCALES + resources). Missing keys automatically fall back to English, so partial translations ship safely. Scaffolds for es, hi, ur, tl already exist.
2. Display currency: add one entry to CURRENCIES in app/src/config/currencies.ts (ISO code, symbol, Intl locale, name key) and, if the new locale should default to it, one line in LOCALE_DEFAULT_CURRENCY. Rates come from the swappable RATE_PROVIDER (free FX API, cached, display-only — on-chain money is always USDC).
3. Localized product terminology (e.g. the giving label "Zakat/Sadaqah" vs "Giving") lives entirely in the locale file — contracts are locale-agnostic by design.

Security

Read SECURITY.md. Highlights: blockhash randomness is validator-influenceable (bounded impact), collateral can under-cover repeat defaults, AutoPay rests on standard ERC-20 allowances, FX rates are indicative, and there is no KYC/regulatory layer — pooled savings face financial regulation that varies by country, so Rota stays on testnet until reviewed per market.

License

MIT (contracts and app). Not audited. Not financial advice.