Study tools

Lexicon · Premise · Recall

GRE, LSAT, and MCAT practice with resumable attempts, delayed feedback, saved notes, and content that keeps its version history.

Status: Published prototypes
Kind: Web products
Stack: TypeScript · Worker APIs · Persistent state

Lexicon vocabulary study interface with a flashcard and review controls — Published Lexicon capture · vocabulary practice

The problem

A study session needs to survive a reload, keep time correctly, and still explain the original answer after its question bank has changed.

What was built

Three study applications with timed practice, resumable attempts, delayed feedback, notes, and study planning.
Versioned questions and answer keys so historical attempts retain their original context.
Authenticated worker APIs and checks for timing, authorization, retries, and answer-key exposure.

What I learned

Content versioning is part of the learning experience. A historical attempt should never silently acquire a different question or answer key.