Double-entry ledger, idempotency, outbox pattern, and API key governance — production-ready in your codebase in a day.
Get the Backend Kit — $299The problem
A user gets charged twice. You have no idempotency layer. You refund manually and hope it doesn't happen again.
A webhook fires. Your server restarts mid-processing. You don't know if the transaction was recorded. You can't replay it.
Your accountant asks for a balance report. You export CSVs and spend three days reconciling numbers that don't match.
Demo
Cold start to live dashboard: one command seeds realistic data across every module.
What's included
Pricing
one-time payment
FAQ
Do I need a financial license to use this?
No. This is software, not a financial service. You're not moving money through this kit — you're using it to track money movements in your own system. Same category as using an accounting library or an ORM.
Do I have to change my existing stack?
No. The kit runs as a separate service. Your Next.js app, your Supabase backend, or any other frontend communicates with it via HTTP using an API key. No shared database required.
Is this production-ready?
The financial primitives are built to production standards: timing-safe key comparisons, balanced double-entry enforcement, atomic outbox writes, and deterministic idempotency — validated with 25+ contract tests. Before going live with real money, add your own rate limiting and error reporting.
Can I extend it with my own modules?
Yes. It's standard NestJS. Add your own modules following the same patterns in the codebase. The code is yours.
What payment processors does this work with?
Any. Stripe, MercadoPago, Polar, WebPay, or your own. The processor handles the actual money movement. This kit handles your internal accounting, audit trail, and event delivery.