Inspiration
As a former grad student who struggled with GRE vocab memorization, I knew traditional flashcards fell short—they lacked context, adaptability, and fun. Watching peers burn out on rote learning, I wanted to build a tool that merged cognitive science (spaced repetition) with modern AI and gamification to make vocab learning intuitive and sustainable.
What it does
Vocabulary Builder is an English learning tool for test-takers (GRE/SAT) and professionals. It delivers targeted word banks, AI-generated context sentences, 2-minute proficiency assessments, and gamified review games—all designed to build retention and practical fluency.
How we built it
We started by curating domain-specific word lists (4.2k GRE, 3.5k SAT, 6k daily words). Using React for the UI, we built card-based learning interfaces, integrated OpenAI API for dynamic sentence generation, and coded a spaced repetition algorithm to schedule reviews. Stripe API was added for premium subscriptions, and MongoDB stored word data and user progress.
Challenges we ran into
Calibrating the spaced repetition algorithm to balance challenge and accessibility was tough—we tested 8 iterations to get the 1/3/7/14/30-day intervals right. AI sentence generation also needed fine-tuning to avoid generic output; we added mode-specific prompts (test vs. daily) to align with user goals.
Accomplishments that we're proud of
We created a tool that feels personalized without login barriers, with accurate vocab assessment scoring that benchmarks users against real GRE/SAT/native speaker standards. The gamified review module boosted beta user engagement by 60%—proving fun and learning can coexist.
What we learned
Cognitive science principles (spaced repetition) are non-negotiable for retention, but user experience makes or breaks adoption. We also learned that AI tools work best when tailored to specific use cases (test prep vs. daily talk) rather than one-size-fits-all.
What's next for this project
We plan to add voice pronunciation support, expand word banks for niche professional fields (tech, business), and build a lightweight progress dashboard. Long-term, we’ll integrate adaptive learning paths that adjust to individual performance gaps.
Built With
- amazon-web-services
- mongodb
- openai-api
- stripe
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