Reza Bina — WritingEssays on privacy, on-device software, and the craft of building independent iOS apps.https://reza-bina.com/en-gbThe state machine I didn't know I hadhttps://reza-bina.com/writing/the-state-machine-i-didnt-know-i-had/https://reza-bina.com/writing/the-state-machine-i-didnt-know-i-had/A tiny bug in my German numbers app — tap play twice and it skips ahead — turned out to be a data race hiding inside a chain of Combine subscriptions. Here's what went wrong, and why swapping Combine for async/await wouldn't have fixed it on its own.Mon, 27 Jul 2026 18:00:00 GMTSwift ConcurrencyArchitectureA model is probabilistic. A checksum is a fact.https://reza-bina.com/writing/a-model-is-probabilistic-a-checksum-is-a-fact/https://reza-bina.com/writing/a-model-is-probabilistic-a-checksum-is-a-fact/How Veil finds personal data in a document and actually removes it — an on-device NER model, a stack of deterministic validators, and the unglamorous work of cleaning up what the model gets wrong.Mon, 27 Jul 2026 00:00:00 GMTOn-device MLPrivacyWhy I build apps that can't see your datahttps://reza-bina.com/writing/why-i-build-apps-that-cant-see-your-data/https://reza-bina.com/writing/why-i-build-apps-that-cant-see-your-data/The case for on-device software — and why 'we never see your data' should be architectural, not a privacy-policy promise.Sun, 26 Jul 2026 00:00:00 GMTPrivacyOn-device