The latest articles on DEV Community by Perfecture (@perfecture). https://dev.to/perfecture https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4099020%2Fc5a65564-01b2-48fd-8eb0-c9cc19917473.png https://dev.to/perfecture en Perfecture Fri, 28 Aug 2026 13:20:34 +0000 https://dev.to/perfecture/i-built-a-slot-alert-system-for-french-prefectures-1kfp https://dev.to/perfecture/i-built-a-slot-alert-system-for-french-prefectures-1kfp <p>French administrative appointments are a nightmare: prefectures release appointment slots at random times, and they vanish in minutes. Titre de séjour, passeport, driving licence medical commission... people refresh pages for weeks.</p> <h3> The problem </h3> <p>Prefecture booking systems are old web forms with no notification feature. Slots appear at 8am or 7pm, gone in 10 minutes. For a driving licence medical commission (a mandatory visit for many drivers), waiting months is normal.</p> <h3> The solution </h3> <p><a href="https://perfecture.fr" rel="noopener noreferrer">Perfecture.fr</a> polls prefecture booking pages continuously and sends an alert the moment a slot opens. Stack: Next.js for the frontend, Python workers for the polling, Supabase for storage, Redis for queues.</p> <h3> Lessons learned </h3> <ul> <li>Slot release patterns are predictable: morning and evening peaks (10h00 and 18h00 see most releases).</li> <li>Alert latency matters more than coverage: users checking a 7h20 slot found it gone by 7h30.</li> <li>Batch size tuning (20 → 5) made watched campaigns much more responsive.</li> </ul> <p>It's in beta and free: <a href="https://perfecture.fr" rel="noopener noreferrer">perfecture.fr</a>. If you've ever fought with a French administrative booking system, you know why this exists.</p> webdev python