Crosswords

A full-stack crossword puzzle app where users pick any topic and difficulty level (Monday through Sunday, NYT-style), and Claude generates a complete 15x15 crossword puzzle in real time. Users solve puzzles in an interactive grid with full keyboard navigation, request AI-generated hints per clue, and track stats over time.

How Generation Works

The generation pipeline has multiple stages:

1. Prompt construction — requests a 15x15 grid with rotational symmetry, minimum 3-letter words, and difficulty-calibrated clues
2. Claude API call — claude-3-7-sonnet with structured JSON output
3. Post-processing — extracts all actual words from the grid, re-numbers cells in reading order, and matches clues back to positions
4. Missing clue backfill — a second Claude call generates clues for any grid words the first pass missed

Features

• Interactive grid — full keyboard navigation, click-to-toggle direction, auto-advance through words, error highlighting
• AI hints — per-clue contextual hints that consider your current progress without revealing the answer
• Auto-save — debounced at 1.5s with optimistic cache updates
• Server-side validation — cell-by-cell answer checking
• Stats dashboard — completion rate, streaks, average time, hints used, breakdown by difficulty and day of week
• Google OAuth — authentication via Auth.js with JWT sessions
• Theming — six color themes persisted to the database

Tech Stack

• Next.js 15 — App Router with 12 API routes
• TypeScript — end-to-end type safety with Zod validation
• Anthropic Claude — puzzle generation and contextual hints
• Prisma + PostgreSQL — game state, user preferences, stats
• Auth.js — Google OAuth with Prisma adapter
• TanStack Query — data fetching with optimistic updates