WebsiteClient work

Kształcenie Słuchu eBook Store

A shop that sells and delivers a music theory e-book directly, with no marketplace in between.

Year: 2026
Status: Live
Role: Solo: design, front end, back end, deployment.

kształceniesłuchu.kkaszuba.eu

Danuta Kaszuba wrote a 404-page book, Kształcenie słuchu z elementami teorii muzyki, and wanted to sell it herself instead of through a marketplace. Visitors can look inside, buy it and download the PDF. Orders are handled from a private admin panel, so the whole process stays in one place.

Stack

Next.js 16
React 19
TypeScript
Tailwind CSS 4
SQLite
Nodemailer
Playwright
Docker
Traefik
Cloudflare Tunnel
Proxmox

In practice

An interactive piano you can play with the mouse or the computer keyboard, and a reader with 20 sample pages and the full table of contents, so the book can be judged before it is bought.
Checkout as a guest or with an account, paying by bank transfer or BLIK to a phone number, with the payment instructions sent by email automatically.
A private admin panel to confirm payments and send the e-book. The send button stays locked until the legally required waiting period has passed.
The PDF reaches the buyer through a single-use download link valid for 7 days, and it stays available in a library in their account.
Customer accounts with email verification, password reset, data export and account deletion.
Terms of sale and a privacy policy built into the checkout. The site records which version each customer accepted and whether they agreed to early delivery.
The author sells directly, with no payment-provider fees and no marketplace commission. The site uses no analytics and no third-party cookies, so there is no cookie consent banner.
Light and dark theme, a contact form, and a layout that works on phones.

How it is built

Next.js 16 on the App Router with React 19 and TypeScript, styled with Tailwind 4.
Orders, accounts and delivery records live in SQLite (the built-in node:sqlite) on a persistent Docker volume. For one book and a modest number of orders a single file is enough, and there is no database server to look after.
The PDF is kept outside the public folder, so it can only be reached through a download link the app has issued. Those tokens are single-use and expire after 7 days.
Download tokens and passwords are stored only as hashes. A leaked database therefore contains no working links and no passwords.
Payment is a bank transfer or BLIK to a phone number, not a card gateway. That is what removes the provider fees, and it is also why confirmation is a manual step in the admin panel, with the email sent by Nodemailer.
Polish consumer law on digital content shaped the order flow. The right of withdrawal is handled in code: the send button stays locked for the waiting period, and each order stores the accepted version of the terms and whether early delivery was agreed to.
The app runs as a standalone Docker image on a self-hosted Proxmox server, behind Traefik and a Cloudflare Tunnel, and is deployed with Prox Hub, the deployment panel I built myself.
Playwright browser tests cover the account, order and delivery flows, which are the parts where a regression would mean a customer who paid and received nothing.