Arjo

Stablecoin-powered group savings, inspired by the age-old ajo rotating-savings tradition practised the world over — rebuilt on the Arc (Circle) Testnet. Pool funds with people you trust, automate payouts, and track everything transparently onchain.

Built with Next.js 14 (App Router), TypeScript, Tailwind CSS, Supabase auth, Circle Programmable Wallets, and live onchain USDC data with an AI circle-health analysis layer.

Note: This runs against Arc Testnet with Circle TEST keys — it's a working testnet/demo, not a real-money production app.

Features

• Auth — email/password + Google OAuth via Supabase.
• Programmable wallets — a Circle developer-controlled wallet is auto-provisioned for each user on Arc Testnet.
• Live onchain dashboard — /circles/[id] reads real USDC balances and transfers straight from the Arc RPC (no mock data).
• AI insights — per-circle health score (0–100), risk-member flags, recommendations, and a 4-week stability forecast. Uses Claude when ANTHROPIC_API_KEY is set, with a deterministic scoring engine as fallback and numerical grounding.

Tech stack

Layer	Choice
Framework	Next.js 14 (App Router), React 18, TypeScript
Styling	Tailwind CSS v3, shadcn-style components
Auth + DB	Supabase (@supabase/ssr)
Wallets	Circle Programmable Wallets (@circle-fin/developer-controlled-wallets)
Chain	Arc Testnet (chain ID 5042002), USDC
AI	Anthropic Claude (optional) + built-in heuristic engine

Local development

npm install
cp .env.local.example .env.local   # then fill in real values (see below)
npm run dev                         # http://localhost:3000

Build & run the optimized production server locally:

npm run build
npm start

Environment variables

Copy .env.local.example to .env.local and fill in. NEXT_PUBLIC_* values are exposed to the browser; the rest are server-only secrets — never commit them (.env.local is gitignored).

Variable	Required	Notes
NEXT_PUBLIC_SUPABASE_URL	✅	Supabase → Project Settings → API
NEXT_PUBLIC_SUPABASE_ANON_KEY	✅	anon public key
NEXT_PUBLIC_SITE_URL	✅	base URL, used for OAuth redirects
NEXT_PUBLIC_ARC_CHAIN_ID	✅	5042002
NEXT_PUBLIC_ARC_RPC_URL	✅	https://rpc.testnet.arc.network
NEXT_PUBLIC_ARC_EXPLORER_URL	✅	https://testnet.arcscan.app
ARC_LOOKBACK_BLOCKS	–	blocks scanned for transfers (default 100000)
ARC_DEMO_ADDRESS	–	fallback pot address for the demo dashboard
CIRCLE_API_KEY	✅	secret — Circle Console
CIRCLE_ENTITY_SECRET	✅	secret — 64-char hex
CIRCLE_WALLET_SET_ID	✅	shared wallet set id
ANTHROPIC_API_KEY	–	enables Claude-written insights
ANTHROPIC_MODEL	–	default claude-3-5-sonnet-latest

Database setup

In the Supabase SQL Editor, run the migrations in order:

1. supabase/migrations/0001_profiles.sql
2. supabase/migrations/0002_circles.sql
3. supabase/migrations/0003_circle_wallet.sql

Deploying to Vercel

1. Supabase — create a project, run the migrations above, copy the Project URL
   • anon key.
2. Push to GitHub — e.g. gh repo create Arjo --private --source=. --push.
3. Import the repo at vercel.com/new. Next.js is auto-detected — no vercel.json needed.
4. Set env vars (table above) in Vercel → Settings → Environment Variables, with NEXT_PUBLIC_SITE_URL = your Vercel domain.
5. OAuth redirects — in Supabase → Authentication → URL Configuration, set the Site URL to your Vercel domain and add https://<your-app>.vercel.app/auth/callback to Redirect URLs. Mirror that callback in the Google Cloud console if using Google sign-in.
6. Verify — sign up, confirm a profile + Circle wallet are created, open a circle, claim test USDC from the Circle faucet, then refresh to see the onchain balance and AI insights populate.