Can I code this? A Language Learning Flashcard App
A well-documented spaced-repetition algorithm plus your own vocabulary cards is a genuinely achievable weekend build — the algorithm is a solved problem, unlike Duolingo's professionally-designed course content.
Build it
Effort: a weekendRunning cost: $0/mo to start
Why CanICodeThis says Build it
Cards with a front and back, organized into decks, are straightforward CRUD
The SM-2 spaced-repetition scheduling algorithm is well-documented and good enough for personal use
A daily review queue showing cards due today is a simple date-based query
The parts that'll cause problems
Professionally-sequenced course content covering a full language is a curriculum-design project, not a coding one — bring your own cards
Speech recognition for pronunciation practice adds real ML complexity beyond text-based review
Image and audio attachments per card are a reasonable but real additional feature
How I'd build this
frontend
Next.js
database
Supabase
auth
Supabase Auth
hosting
Vercel / Cloudflare Pages
MVP scope
Create decks and cards (front/back text)
SM-2 spaced-repetition scheduling
A daily review queue
Basic stats (cards reviewed, accuracy)
Postpone to v2
Audio pronunciation attachments
Speech recognition practice
Pre-built starter decks for common languages
What it actually costs to build
AI agent — with a subscription (Claude Pro/Max, Cursor, etc.)
$0 marginal
AI agent — pay-per-use API, no subscription
$43–$86 one-time
Hosting, once it's running
$0/mo (free tier)
Domain name, if you want your own
~$12/yr
Existing tools solving a similar problem typically run $6.99–$6.99/mo — see how they compare below.
The build prompt
Build me a spaced-repetition flashcard app, genuinely achievable in a weekend:
1. Decks containing cards with a front and back — ordinary CRUD.
2. The SM-2 spaced-repetition scheduling algorithm — well-documented and good enough for personal use, don't invent your own scheduling logic.
3. A daily review queue pulling cards due today per the SM-2 schedule.
4. Basic stats (cards reviewed, accuracy) over time.
No pre-built course content — bring your own cards. That's a real, complete spaced-repetition tool. Out of scope: audio pronunciation attachments, real, separate file-storage scope, and speech recognition practice, which needs a genuinely different, specialist audio-ML capability beyond text flashcards.