Vayoo

Challenge

Microfinance operators (cheque cashing, gold buy, FX, short-term loans) typically operate on a stitch of spreadsheets, paper receipts, and per-product legacy software — none of which agree about what cash is in the till at end of day. Regulatory expectations are rising. The brief: build one platform where the till, the loan book, the FX inventory, and the gold log all roll up into one auditable money model, with tenant isolation so a multi-branch operator can run several locations without crossover.

Approach

1. 01

   Built Next.js 15 + Prisma + Supabase Postgres as the core, with Supabase Auth for staff identity and Supabase Storage for private customer documents and ID images.

2. 02

   Designed a ledger-backed money model from day one — every till transaction, loan disbursement, cheque cashed, gold purchase, and FX trade lands on a double-entry-style journal with reconciliation tooling, not a free-floating balance.

3. 03

   Enforced tenant isolation via Prisma + SQL RLS policies that live in the migration files (the schema is the source of truth, not a separate policy document).

4. 04

   Layered Upstash Redis for rate limiting, idempotency keys, short-lived locks on till operations, and cached FX rate snapshots.

5. 05

   Built a forms-heavy UI on React Hook Form + Zod with shared validation between server actions and clients, plus a full QA harness covering form alignment, cheque cashing parity with the legacy tool, and approval-flow regression.

6. 06

   Added approvals on operations above per-role thresholds (e.g. cash advances over a tier limit) with audit trail and per-action reasoning.

Outcome

End-of-day reconciliation moves from "count and pray" to a tally against a journal the system kept all day. Multi-branch operators run several locations under one tenant boundary with no data crossover, and the audit trail satisfies the standards a regulator or acquirer expects without manual evidence collection.