Case Study — Evidence-Gated

Quiz of Koko — from idea to live product

How Quiz of Koko went from a real learning problem to a live, AI-powered vocabulary game — the same FDE loop I now run for clients.

● Live — free in the browser and on AndroidForward Deployed Engineering — idea to live product, end to end

The challenge

Vocabulary practice has a motivation problem, not a content problem: dictionaries and flashcards exist everywhere, yet learners quit within days because nothing adapts to them and nothing is at stake.

The goal was never “another quiz app”. It was to prove that a small, sharply-scoped product — adaptive questions, real-time duels, weekly stakes — can keep a learner coming back without a content team or a marketing budget.

The FDE loop, run for real

  1. 1

    Scope — the honest cut

    One job done completely: help a Persian-speaking learner keep and grow vocabulary. Everything that did not feed that job went to the kill list — a scope discipline now sold as the first step of every client sprint.

  2. 2

    Design — riskiest assumptions first

    Adaptive difficulty and duel mechanics were designed before pixel-polish: if the questions did not feel personal and the duels did not feel alive, nothing else mattered.

  3. 3

    Build — AI-accelerated, human-judged

    The product was built the way the MVP Sprint builds today: AI for speed on the well-understood parts, human judgment on architecture and the learning feel — shipped to real users in the browser first, then Android.

  4. 4

    Launch & learn — instrumented, not decorated

    Analytics tied to outcomes (retention, duel participation, review completion) instead of vanity counters — and the growth plan runs against pre-registered gates, so every decision has an evidence rule.

What shipped

Adaptive AI questions

Personalized question generation that tracks each learner’s level and gaps.

Koko Plus — smart review

Spaced-repetition vocabulary review, scheduled by what you actually forget.

Live 1v1 duels

Real-time head-to-head matches — the stake that makes practice feel like play.

Weekly cup & leagues

Bronze→Champion weekly leagues — a reason to come back every week.

Continuous diagnosis

The app learns where you slip and re-tests exactly there.

Evidence, not adjectives

  • The product is live and verifiable right now: free in the browser and on Android — no screenshots-only “case study”.
  • Growth runs against pre-registered gates (day-1 retention, day-7 retention, conversion, CAC). The gates are public discipline; numbers get published when the evidence is honest and the owner approves.
  • The entire investor funnel shipped through the same loop: an 11-slide pitch deck, an investor page, and a 19-post bilingual series documenting the deck slide by slide.
The same FDE loop, productized

Want this loop on your product?

A free 30-minute scope call gets you the honest cut: the real problem, a one-page scope, and a build / don’t-build verdict — even if we never work together.