api.koydo.app

Deterministic engines,
one developer API.

Learning science, gamification, math, and music economics — as four JSON APIs. Same request in, byte-identical response out. No model hosting, no per-call AI cost. Stop rebuilding spaced repetition, adaptive testing, and royalty math.

Read the docs

$0.001 per call, metered monthly · free catalog endpoints · per-key rate limits

Four engines

Learning Science API

Spaced repetition, Bayesian mastery tracing, adaptive testing, exam readiness, misconception detection.

Gamification API

XP & levels, an idempotent soft-currency economy, streaks, rewards, leagues, skill rating, FSRS review.

Math Engine API

Parametric problem generation, exact answer grading, adaptive selection, geometry & stats.

Music Economics API

Royalty splits, mechanical & performance royalties, streaming economics, quality gates, identifiers.

Pricing

One simple meter. $0.001 per API call, billed monthly through Stripe. GET catalog endpoints are free. Free keys are rate-limited (60 burst, 1 req/s); paid keys get 600 burst, 10 req/s.