Prepady
AI-powered adaptive exam prep for Africa — 60+ national exams across 30+ countries (WAEC, NECO, JAMB, KCSE, Matric, ZIMSEC, the Baccalauréat and many more — see src/lib/exams.ts).
Prepady is the "EduCore — Adaptive Learning Engine" product: adaptive practice tests, a real past-questions bank, and an AI layer that explains every question. Built on the same proven stack as Myedupady (Next.js 15 + Payload CMS 3 + Postgres), with Claude added as the AI tutor.
Design: a warm, premium "Indigo & Gold"-replaced cream / ink / gold palette with a soft pastel tone per region — all driven from one token register (globals.css → tailwind.config.ts → theme.ts).
Status — MVP foundation scaffolded
This repo is the foundation, bootstrapped from the battle-tested Myedupady stack. What's in place:
- ✅ Next.js 15 + Payload CMS 3 + Postgres app skeleton, build scripts, admin panel
- ✅ Data model:
Users (with freemium subscription + AI metering), Subjects, Questions (MCQ + theory, past-question bank), QuizSessions, Media
- ✅ Exam taxonomy (WAEC/NECO/JAMB/Post-UTME/IGCSE/A-Level) and adaptive quiz helpers
- ✅ AI "Explain this to me" —
lib/ai.ts + POST /api/ai/explain, gated by the freemium paywall
- ✅ Landing page
Not yet built (next steps — see Roadmap): the student-facing CBT quiz UI, signup/login pages, the dashboard, the Paystack subscription flow, and the first DB migration. These all have direct, working references in the edupady sibling repo to lift from.
Architecture
| Layer | Choice | Notes |
|---|
| Framework | Next.js 15 (App Router, TS) | Same as edupady |
| CMS / Admin / Auth | Payload CMS 3 | /admin; built-in auth |
| Database | Postgres (Neon/Supabase) | Migrations via Payload |
| Styling | Tailwind + shadcn/ui | Primitives lifted from edupady |
| Payments | Paystack | NGN subscriptions (Phase 1) |
| AI | Claude (@anthropic-ai/sdk) | Explain / step-by-step / essay marking |
| Offline | PWA + service worker | Phase 2 |
The three EduCore pillars → where they live
- Adaptive tests →
QuizSessions + lib/quiz.ts (adaptive difficulty, streaks) + the question bank. ~70% lifted from the proven Myedupady engine.
- Video + NERDC curriculum → Phase 2 (Subject → Topic → Concept → {video, notes, questions}).
- AI explanation layer →
lib/ai.ts + /api/ai/explain (built); essay marking + topic follow-ups in Phase 3.
AI model choice = cost control (the revenue lever)
AI calls cost money per use, so model choice is deliberate and per-feature (env-configurable in lib/ai.ts):
| Feature | Default model | ~Cost / action | Why |
|---|
| "Explain this" / step-by-step | Haiku 4.5 ($1/$5 per 1M) | $0.0025 (**₦4**) | High volume, must be cheap |
| Hard maths / tough explanations | Sonnet 4.6 ($3/$15) | ~$0.01 | Optional upgrade |
| Essay / theory marking (Phase 3) | Sonnet 4.6 (Opus 4.8 for premium) | $0.025–0.05 (**₦40–80**) | High value; meter it |
A paying student doing 50 explanations + 5 essays/month ≈ **$0.25–0.40 (₦400–650)** in AI cost — comfortably under a ₦1,500–3,000/month subscription provided the expensive actions (essay marking, unlimited AI) sit behind the paid tier and daily caps. Free tier is metered at FREE_DAILY_AI_LIMIT (5/day) in lib/quiz.ts.
Bump quality any time by setting AI_EXPLAIN_MODEL=claude-opus-4-8 etc. — it's a config decision, not a code change.
Revenue model — freemium subscription
- Free: daily adaptive practice + limited daily AI + past-question samples (acquisition).
- Premium: unlimited AI, full timed CBT mocks, essay marking, full past-question bank. Monthly / termly / JAMB-season bundles, priced in NGN.
- Later channel: school/B2B seat licences (Phase 2+).
Getting started
pnpm install
cp .env.example .env.local # fill in DATABASE_URI, PAYLOAD_SECRET, ANTHROPIC_API_KEY
pnpm generate:importmap # regenerate the Payload admin import map for this config
pnpm migrate:create initial # generate the first migration (over a :5432 connection)
pnpm migrate # apply it (⚠ use a SESSION pooler / :5432, not :6543)
pnpm dev # http://localhost:3000 · admin at /admin
pnpm generate:types # regenerate payload-types.ts after schema changes
Migration gotcha (inherited from edupady): Payload migrate hangs over a Supabase transaction pooler (:6543). Run migrations over the session pooler / direct connection (:5432); the runtime app can stay on :6543.
Roadmap
Phase 1 — MVP (fastest to revenue)
Phase 2 — Content & reach
Phase 3 — AI depth
Out of scope (content, not code)
Question banks, NERDC curriculum, concept videos, and marking schemes are content the client produces — same boundary as edupady. The code provides the structures and AI; the teaching content is loaded via /admin.
