Idempotent transactions
Client-generated request identity prevents duplicate visual commits and models production retry safety.
Technical demo for full-stack reliability
A fintech-grade ledger app built inside one Next.js project.
This technical demo combines Auth.js v5, Prisma, local API route handlers, wallet balances, payment-like transfers and audit-friendly transactions in one deployable Next.js app.
Next.js API routesAuth.js v5JWT sessionsPostgreSQLPrismaTypeScript
Live ledger mock
Wallet control plane
Balance
$12,840
Sent
$4,210
Received
$8,630
DEBIT reference_82aT+1
CREDIT reference_82aT+2
DEBIT retry-safeT+3
Built for API reliability
Hard problems surfaced as product UX.
The interface turns reliability concerns into visible states: authenticated sessions, retry-safe payments, ledger movement tables and audit-ready signals.
Wallet ledger
Debit and credit movements are stored as auditable ledger events instead of mutable balances only.
Transactional consistency
Next.js route handlers coordinate Prisma transactions around balance checks, debit, credit and transaction creation.
Auditability
Each movement carries reference IDs, descriptions and timestamps for reconciliation-style inspection.
Reconciliation mindset
The UI exposes sent, received, last activity and ledger health signals for operational review.
Auth.js JWT
Protected flows use Auth.js v5 credentials, encrypted JWT sessions and the server-side AUTH_SECRET.
Ledger-first architecture
Moves are modeled as transaction rows with shared references for debit and credit sides.
What this demo proves
The UI exposes auth, protected pages, payment-key resolution and transfer confirmation.
Premium product finish
The local API is presented with mobile-first forms, motion, protected states and operational empty screens.
Duplicate requests do not create duplicate visual transactions in the client flow.Start demo