Campaign engineering · Easter egg · Concurrent code claims
Bu Forma Fenerbahçe’den Yapıldı: a hidden campaign with one-time codes
An adidas and Fenerbahçe campaign site with a hidden Easter egg and a server-side voucher claim flow designed to prevent duplicate discount-code assignments during concurrent requests.
My role: I designed and implemented the campaign’s hidden interaction and the server-side code-claim experience.
The challenge
Make a promotional reward feel like a discovery inside the campaign while distributing a limited pool of single-use codes safely, including when multiple visitors claim at nearly the same time.
The approach
A hidden adidas and Fenerbahçe mark appears in a randomly selected page section and corner as that section enters view. Selecting it opens the Easter egg. The claim path checks the campaign window and request origin, issues a short-lived participant-bound HMAC challenge, applies rate limits, and delegates final code allocation to a PostgreSQL claim function.
Technical scope
The implementation uses Next.js and React, Istanbul-time campaign-window checks, a two-minute HMAC-SHA256 challenge bound to a participant cookie, trusted-origin validation, rate limiting, and a PostgreSQL-backed code claim. The database claim path is the final gate that prevents the same voucher from being assigned to concurrent claimants.
Outcome
The Easter egg connected a playful discovery to a controlled, single-use reward flow. Each participant could claim one code, and concurrent claims were handled through the database-backed allocation path.