Flash

Flash is a flashcard study app that uses spaced repetition to help you learn and retain information. It's built with Ruby on Rails, renders its views with Phlex instead of ERB, and wears a distinctive "Terminal Scholar" look.

One upload becomes reusable content: a data set of terms that can be studied as several deck "forms" — the original front→back text deck, a reverse deck (answers become prompts, no re-upload), or a microphone-driven music deck. Public decks can be browsed and copied from a catalog, or shared privately via a revocable link.

For architecture, conventions, and the data model in depth, see AGENTS.md.

Tech stack

• Ruby 4.0.5 / Ruby on Rails 8.1.3
• PostgreSQL
• Hotwire (Turbo + Stimulus), TypeScript bundled with esbuild
• Phlex for views
• Creem for subscription payments
• Node 26.3.1, managed with pnpm 10.26.1

Getting started

Prerequisites

• Ruby 4.0.5 (see .ruby-version)
• PostgreSQL, running locally
• Node 26.3.1 and pnpm 10.26.1

Setup

bin/setup

This installs Ruby and JS dependencies, prepares the database, and starts the development server. To set up without booting the server, run bin/setup --skip-server. To drop and recreate the database, use bin/setup --reset.

Running the app

bin/dev

bin/dev uses foreman and Procfile.dev to run the Puma web server (port 3000) alongside the JS and CSS watch/build processes. The app is then available at http://localhost:3000.

Configuration

Environment variables are loaded from .env files:

• .env.local — development values, not committed
• .env.test — test values, committed
• .env.example — template of required variables, committed

Variables used by the app:

• CREEM_API_KEY — Creem payment API key
• CREEM_PRODUCT_ID — Creem product ID for the subscription checkout
• CREEM_WEBHOOK_SECRET — secret for validating Creem webhooks

HONEYBADGER_API_KEY configures error reporting when set.

Never commit .env.local or any file containing real API keys.

Testing

Ruby tests use RSpec:

bundle exec rspec        # full suite
bundle exec rspec path/to/spec.rb

JavaScript/TypeScript tests use Vitest. pnpm test runs type-checking and linting first, then the suite (100% branch and function coverage is enforced):

pnpm test                # tscheck + eslint + vitest
pnpm vitest              # vitest only

Linting & security

bin/rubocop              # Ruby style
pnpm eslint              # JS/TS style
pnpm stylelint           # CSS style
pnpm tscheck             # TypeScript type check

bin/brakeman             # static security analysis
bin/bundler-audit        # gem vulnerability audit

Contact

• Support: support+flash@boon.gl
• GitHub: https://github.com/mockdeep/flash