TempPower Pro: Automating Electrical Compliance

The Core Problem: Electrical engineers in the UK were losing hours performing complex BS 7909 / BS 7671 temporary-power calculations (voltage drop, Zs, PSCC) manually or on scattered spreadsheets. The existing standalone calculators had no database, meaning users couldn't save projects, manage client records, or collaborate. There was a desperate need for a centralized, compliant, and monetizable SaaS platform.

The Technical Solution: I architected and built a complete SaaS platform from the ground up using Next.js 15.

• Architecture & Auth: Implemented robust session handling using NextAuth v5, wrapping the client in a SessionProvider and securing every route.

• Database & Logic: Designed a PostgreSQL database via Prisma (Edge runtime) with a complex Project JSON model for distribution boards, handling owner/editor access controls. Completely rewrote the distribution-board designer with strict TypeScript and typed server actions.

• Monetization: Integrated Stripe with complete plan gating (Free/Pro/Team). I handled checkout routes, webhooks, and the billing portal, enforcing PLAN_LIMIT directly on the server-side with Zod validation.

Measurable Business Impact: The platform successfully transitioned from a free static tool to a revenue-generating SaaS. It reduced complex calculation time from over an hour to under 5 minutes per project. The automated compliance checks eliminated human error in BS 7671 standards, and the platform successfully onboarded a rapidly growing base of paying engineering teams in its first month.

Tech Stack: Next.js 15, TypeScript, NextAuth v5, Prisma, PostgreSQL, Stripe, Zod, Tailwind CSS, Vercel.