DEV is the engineering notebook of the teams building Hookay. We write about the craft of privacy-preserving product engineering: the patterns, the trade-offs, and the times a constraint made the product better. If RED is what we learn from attacking our systems, DEV is what we learn from building them.https://dev.hookay.eu/https://dev.hookay.eu/posts/why-we-write-before-we-launch/https://dev.hookay.eu/posts/why-we-write-before-we-launch/Hookay isn't live yet. Starting the engineering notebook now — while the decisions are still warm and nothing is too embarrassing to admit — is itself one of those decisions. What this site is for, what we'll publish during the build, and the editorial rules we're committing to in public.Tue, 02 Jun 2026 00:00:00 GMThttps://dev.hookay.eu/posts/testing-a-social-app-with-no-users/https://dev.hookay.eu/posts/testing-a-social-app-with-no-users/Proximity discovery, feed ranking, k-threshold suppression — every core feature of Hookay depends on crowd behavior, and our crowd doesn't exist yet. How we build and test a location-based social product pre-launch: synthetic populations, simulated cities, and the bugs only fake people can find.Tue, 12 May 2026 00:00:00 GMT