Own product (in progress) · 2026
Calculo — invoicing for small businesses
Estimates, invoices, formula-based pricing and Stripe payments for small service businesses.
Why
Every small business I have worked with rebuilds the same estimate → invoice → payment flow. Calculo is that flow as a product: clients, products, templates, a formula engine for pricing rules, PDF documents and Stripe payment links.
How it runs
A Turborepo monorepo: Next.js app with tRPC routers per domain (clients, estimates, invoices, payments, templates, formulas), Prisma on Postgres, shared packages for the formula engine and email templates. Tenant scoping, status transitions and plan limits are covered by tests.
Status
Private beta. Ask me for a walkthrough if your business needs invoicing done properly.