Next.js · Rental · Payments

E-BikeRent — online e-bike rentals with payments, invoices and an admin panel

e-bikerent.ro ↗

1 month ago·

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·3 min read

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Context

E-BikeRent rents electric bikes in Predeluț, Bran. I built the site and the admin panel behind it, and I've been working on it since March 2022 — over 1,700 commits so far.

The problem

Renting a bike online sounds simple until you add everything around it: picking bikes and accessories for a date and duration, paying by card, issuing an invoice, emailing the customer, and later cancelling, refunding or reversing that invoice without leaving the books in a mess. On top of that, the team wanted to manage stock, gift coupons, local trails and SEO themselves.

What I built

• A bilingual public site (RO/EN): home, bikes, cart, checkout, gift coupons, local trails with their own pages, about, FAQ, contact and legal pages, plus a payment-link page for orders paid later.
• Gift coupons, including a Christmas campaign with its own payment webhook.
• An admin panel: dashboard, bookings, bikes, accessories, stock, coupons, trails, SEO and settings.
• Order operations that are safe to repeat: cancel, invoice reversal, regenerate, full or partial refund, payment links and a sync with EuPlătesc. Every operation is idempotent and written to an order log.
• Trails with GPX files and a gallery with drag-and-drop ordering and per-file upload progress.

Under the hood

A few rules keep the money and the stock honest:

• Money is always an integer in bani and goes through dinero.js. Prices are copied onto the order line when it's saved, so an issued invoice never changes later.
• Availability has one formula, in one file: stock + extra − blocked − reserved. It was consolidated after two separate calculations disagreed, which is exactly the kind of bug that lets a bike in for service still be booked.
• Writes go through server actions that check the session and validate with zod. In the 2026 rebuild, 29 API routes were removed and only 5 kept — among them auth, the EuPlătesc webhooks and an upload with a progress bar. A repository layer was removed too: 496 lines, 73% of which were single Prisma calls.
• Login is a magic link via Better Auth, rate limited in Redis per IP and per email, and the form answers the same way whether or not the address exists.
• Migrations are safe to re-run, because the production database had been changed by hand over the years.

The 2026 v3 rebuild, planned in 15 phases, moved the project from the Pages Router to the App Router on Next.js 16 and React 19, from Tailwind 3 to 4, from next-i18next to next-intl, from Supabase Auth to Better Auth, from nodemailer to Brevo and from next-seo to the Metadata API, with SEO editable from the panel. The panel itself was rebuilt on shadcn/ui and recharts. Public URLs stay translated and unchanged, so pages already indexed keep their rankings.

Status

The live site has been taking bookings for years. The v3 rebuild is complete on its own branch, with Vitest covering money, availability, cart capacity, coupons, bikes and login throttling.

Stack

Next.js 16, React 19, TypeScript, Prisma 7 (PostgreSQL), Better Auth, next-intl, Tailwind CSS 4, shadcn/ui, zustand, zod, react-hook-form, dinero.js, recharts, Leaflet, Redis, EuPlătesc, Oblio, Brevo, Supabase Storage, Google Maps, Cloudflare Turnstile, Vitest.