Curriculum and research
Bóyǎ does not invent the HSK framework, and we do not invent the science behind spaced repetition. We build on both, and we name the people who built them first.
HSK 3.0
Hanban / Center for Language Education and CooperationVocabulary, character, and grammar standards for HSK levels 1–6 that anchor our curriculum tree.
License: Used under the standard's educational-use provisions; HSK is a trademark of its rights holder.
FSRS — Free Spaced Repetition Scheduler
Jarrett Ye and contributorsThe scheduling algorithm that decides which card a child should see next.
License: MIT License
Input Hypothesis
Stephen KrashenTheory behind our 'comprehensible-input-just-above-current-level' lesson sequencing.
License: Cited as research; no code or text reused.
Desirable difficulties research
Robert and Elizabeth BjorkInforms our duel difficulty curves and retrieval-practice cadence.
License: Cited as research; no code or text reused.
Typography
The fonts that carry the Imperial Game look. All four are open-source under the SIL Open Font License and served via Google Fonts.
Noto Serif SC
Google / AdobeDecorative hanzi and Simplified Chinese display text.
License: SIL Open Font License 1.1
Playfair Display
Claus Eggers SørensenEditorial Latin display — the headline voice from the brand book.
License: SIL Open Font License 1.1
DM Sans
Colophon Foundry / Indian Type FoundryBody and UI text.
License: SIL Open Font License 1.1
Space Grotesk
Florian KarstenGamification numerals — XP, streaks, duel timers (tabular figures).
License: SIL Open Font License 1.1
Services and infrastructure
Bóyǎ uses a small, named set of third-party services. Each is listed in the Privacy Policy as a subprocessor.
Anthropic Claude
AnthropicThe model that powers 老师 Lin, our AI tutor. Voice transcripts are not used to train Anthropic models.
License: Used under Anthropic's commercial terms.
LiveKit
LiveKit, Inc.Real-time voice and video transport for the tutor, encrypted in transit.
License: Server is Apache 2.0; we use the hosted product under LiveKit's terms.
Supabase
Supabase Inc.PostgreSQL database, authentication, and storage. SOC-2 Type II.
License: Open source (Apache 2.0 / PostgreSQL); we use the hosted product.
Next.js
VercelThe React framework that runs the Bóyǎ web app.
License: MIT License
Sentry
Functional Software, Inc.Error logging and performance monitoring, scrubbed of personal data.
License: Used under commercial terms.