Qubba Apps bloghttps://qubba.ai/apps/blogNotes from building StudyOS and QScan: learning science, food scoring, and launching apps in 2026.enWhy an AI tutor must cite its sources (and how grounding works)https://qubba.ai/apps/blog/ai-tutors-that-cite-sourceshttps://qubba.ai/apps/blog/ai-tutors-that-cite-sourcesMon, 07 Sep 2026 08:00:00 +0000A tutor that cites the page it learned from can be checked. Why language models guess, how grounding works, and what a real citation looks like.hello@qubba.ai (FiLo)E numbers and food additives: what EFSA and the FDA actually sayhttps://qubba.ai/apps/blog/e-numbershttps://qubba.ai/apps/blog/e-numbersMon, 07 Sep 2026 08:00:00 +0000What an E number means, how EFSA and the FDA approve and re-evaluate additives, and what the record shows on titanium dioxide, aspartame and Red No. 3.hello@qubba.ai (FiLo)How food scanner apps calculate a score, and why it should be publichttps://qubba.ai/apps/blog/food-scoring-appshttps://qubba.ai/apps/blog/food-scoring-appsMon, 07 Sep 2026 08:00:00 +0000Food scanner apps blend a nutrient profile, an additive penalty and a processing class into one number. How the common formulas work and why they should be public.hello@qubba.ai (FiLo)How to launch an app with a waitlist in 2026https://qubba.ai/apps/blog/how-to-launch-an-apphttps://qubba.ai/apps/blog/how-to-launch-an-appMon, 07 Sep 2026 08:00:00 +0000A practical playbook for launching an app with a waitlist: the one promise page, TestFlight and Play testing limits, pre-orders, email rules and launch day.hello@qubba.ai (FiLo)Spaced repetition explained: why self-scheduling flashcards workhttps://qubba.ai/apps/blog/spaced-repetitionhttps://qubba.ai/apps/blog/spaced-repetitionMon, 07 Sep 2026 08:00:00 +0000Spaced repetition schedules each review just before you would forget. Here is the evidence behind it, how SM-2 and FSRS set the gaps, and how to use it for an exam.hello@qubba.ai (FiLo)