How I Built a Financial Dashboard for Startups

I'm a solo founder building culta.ai — a financial management platform that helps early-stage founders track budgets, burn rate, and cash flow without needing an accountant. Here's a quick look at the stack and a few things I learned along the way. * The Stack * Next.js 15 (App Router) + React 19 Prisma + PostgreSQL Stripe for billing and Connect NextAuth for authentication Tailwind CSS for styling Deployed on Railway * Multi-Entity Architecture * One thing I needed early was support for multiple businesses per user. A freelancer might have a consultancy and a side project — they shouldn't need two accounts. Every dashboard query is scoped to the selected entity using a React context provider. Switching between businesses is instant, no page reload. * Free Financial Calculators as a Growth Channel * Instead of just blogging, I built 17 interactive calculators — burn rate, runway, SaaS pricing, unit economics, and more. Each one is its own page, targets a specific keyword, and funnels u