Ticket sales with QR check-in, built by Claude Code on Elements
Shows with posters and ticket types, card checkout, one QR code per ticket by email, sales per show, and a phone door check-in with a live count.
How it's built
Gatestub needed guest card checkout, QR code tickets by email, a phone door page, and live ticket and check-in counts. Each of those is a part of Elements, so the agent spent its 22 minutes on the venue's night itself.
- Live ticket counts. Ticket types are a LiveTable. Database triggers keep sold and checked-in counts current as tickets are issued and scanned and broadcast each change, so tickets remaining and checked in versus sold update on every open screen.
- Card checkout with just an email. Checkout reads prices and stock under a row lock, holds the tickets and sends the fan to Stripe. Tickets are issued when the fan returns and again when Stripe's webhook arrives, once either way. Until a Stripe key is set, the pay button opens a test checkout inside the app that records the payment through the same function, so tickets and emails work from the start. With one secret key it goes to Stripe, and in production the app registers its own webhook on the first checkout.
- Ticket emails from a job. Issuing tickets schedules a job in the same transaction, and it emails one QR code per ticket, inline and as an attachment.
- Door check-in. Door staff scan a QR code with the phone's camera or search by name, and an
@rpcfunction admits each ticket once and answers valid, already checked in or not found. - Sessions and roles. Admin and door accounts sign in to their own pages, and admins create shows and see sales per show.
- Data from SQL files. Migrations define the schema and seed four upcoming shows with drawn posters and sales, plus tonight's show with 141 of 230 checked in. The project server applied each one as soon as it was saved.
Why Elements
Elements is an integrated full-stack app framework and a project server. The project server checks the agent's work as it builds: it type-checks the server and browser code, analyzes the program, applies migrations and runs the tests, then reports the results to the agent. A security mistake, such as calling a server-only function from the browser, is a compile error. The agent reads the report and fixes its own mistakes before it tells you a feature is done. The same checks run on every feature you ask for next.
Run it yourself
- 1 Sign up
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- 2 Install and run the demo One prompt to paste into your agent.
The prompt
What Claude was given to build this app.
Build an event ticketing app named gatestub for a small music venue. FAN - Upcoming shows with poster image, date, doors time and ticket types (general admission, balcony) with prices and quantities. - Buy tickets with email and card, no account. - Get an email with one QR code per ticket. VENUE (accounts: admin and door staff) - Admins create shows and ticket types, and see sales per show. - Door check-in page for phones: scan a ticket's QR code with the camera, or search by name. Shows valid, already checked in, or not found, loud and clear. - Live count of checked in versus sold. Payments by Stripe. Seed one admin, one door account, four upcoming shows with poster images and ticket sales, one show tonight partly checked in. Show the logins on the sign-in page. Tickets remaining and check-in counts update in real time.