Product Architecture

A composable, metadata-driven platform engineered for NGN simulation at scale.

System map

Client Apps

Flutter iOS · Android · Web

↓

Edge API Gateway

Rate limits · JWT · request signing

↓

NGN Engine

Rules · scoring · adaptivity

Analytics

Mastery · cohorts

Vimeo Pipeline

DRM lectures

Billing

Stripe · plans

↓

Supabase · PostgreSQL

RLS · realtime · storage

↓

Audit + Observability

Logs · SOC2-ready trails

NGN engine flow

1. Request next item
Engine receives student state: mastery vector, recent errors, cadence.
2. Rule evaluation
Metadata rules score candidates by category gap, difficulty fit, recency.
3. Adaptivity
Item sampled probabilistically — never the same template twice in a session.
4. Scoring
Polytomous scoring for SATA / Cloze / Hot Spot with partial credit.
5. Mastery update
Bayesian update on category & sub-skill vectors; persisted to profile.

Items / week

3.8M

p95 latency

142ms

Uptime SLO

99.95%

Concurrent sessions

12k

Roadmap to CAT